Chronic diseases. If you are chronically ill, for example, with an ulcer, ...
UDC 621.73
FINITE ELEMENT MODEL FOR CALCULATION OF THE VALUE OF ACCUMULATED STRAIN IN THE PROCESS OF HOT ROLLING OF RINGS
© 2009 F.V. Grechnikov1, E.V. Aryshensky1, E.D. Beglov2
1 Samara State Aerospace University 2 OJSC "Samara Metallurgical Plant"
Received February 13, 2009
A finite element model for calculating the degree of accumulated deformation at various stages of deformation of an annular blank has been developed. Comparison of simulation results and experimental dependencies confirms the adequacy of the model.
Key words: ring rolling, macrostructure, recrystallization, accumulated strain, finite element method, model, stiffness matrix, equal-strength inserts.
In the practice of GTE production, ring parts with multifunctional purposes are widely used. High demands are placed on these parts in terms of structure and level of mechanical properties. The main way to obtain ring parts is hot rolling (Fig. 1). A feature of this process is the presence of multiple acts of local deformation of the workpiece at the time it is in the rolls and the accompanying multiple partial recrystallization in interdeformation pauses, which makes it difficult to calculate the total (cumulative) deformation for the process.
This leads to the fact that along the section of the workpiece there can be simultaneously different degrees of deformation, including critical degrees of deformation. In turn, critical degrees of deformation contribute to the formation of coarse grains during the final recrystallization annealing. At the same time, in places where the deformation exceeded critical values, a fine-grained structure will form. Thus, the inhomogeneity of deformation leads to inhomogeneity, i.e., structural inhomogeneity over the section of parts and a decrease in the level of mechanical properties. To avoid this, it is necessary to know at each stage the value of the accumulated deformation obtained by the metal both at each local stage of deformation and for the entire period of rolling as a whole. In this regard, the purpose of this article is to build a mathematical model that allows you to determine the stress-de-
Grechnikov Fedor Vasilyevich, Doctor of Technical Sciences, Professor, Corresponding Member of the Russian Academy of Sciences, Vice-Rector for Academic Affairs. Email: [email protected] Aryshensky Evgeny Vladimirovich, post-graduate student. Email: [email protected]
Beglov Erkin Dzhavdatovich, candidate of technical sciences, leading engineer. Email: [email protected]
the formed state and the magnitude of the degree of accumulated deformation.
When developing the finite element model, it was taken into account that, due to symmetry, the structure and properties of the rolled ring are identical for all sections along the circumference. Considering this circumstance, the model was built not for the entire ring, but for a segment equal to 6 lengths of the deformation zone. The segment is divided into triangular finite elements, as shown in Fig. 2.
The angle p, which determines the position of the element in the solution area, is found by the following formula.
12 1 ■ kg
(2YAN + 2YV) , (1)
where YAN, YB - outer and inner radii of the ring;
K - the average radius of the ring in 1 turn.
b is the length of the arc of contact with any of the rolls. To determine it, the formula is applied
b 1(2) AN, (2)
Rice. 1. Scheme of the process of hot rolling of rings: 1 - workpiece, 2 - internal non-driven roll (mandrel), 3 - external drive roll, 4, 5 - guide rollers, 6 - limit switch (diameter control)
where R2 are the radii of the driven and non-driven rolls
A b - absolute compression First, we divide the solution area into quadrangular sectors, each of which corresponds to two neighboring triangular elements. There are N rows of sectors in the radial direction and M in the tangential direction. There are 2 ■ N ■ M triangular elements and (M + 1) ■ (N + 1) nodes. The numbering of nodes is shown in fig. 2. We denote the coordinates of the 1st node along the axes 1 and 2 as xts, X "2
WCH)] HMMM)| ;<3>
1 EVn.+Dn-Dn then!± ^toD
During the calculation, the coordinates of the nodes at any point in the calculation area will change to
displacement of nodes n, 2 . To find n, 2 we use the energy method . Consider a separate triangular element 1 with nodes 1, 2, 3 in Figure 3.
Let us assume that the element is initially not stressed, the nodal forces are equal to 0. Then the forces A, Y, /3 are applied to the corresponding nodes of the element. New config
The node distribution will have an offset d 11, d "12, d, d22, d ^, d 32. The upper index refers to the element, in the future we omit it. The first lower index refers to the node, and the second to the coordinate. Potential energy I of the new configuration in relation to the initial one is the difference between the energy of the stressed state accumulated in the element and and the work done by the forces /2,/3 on the displacement vector e, .
I = u-W = 2 |
Fig 3. Setting the boundary conditions in the problem of segment deformation
where e12 ....... - displacements in the nodes of the element
in directions 1,2 respectively;
/p ...... /32 - forces under the influence of which
there is a displacement of nodes in the direction of 1.2, respectively;
e11 e22 - normal, and e12 - tangential components of the strain tensor;
y11y22 - normal, y12 - tangential components of the stress tensor.
The integration is carried out over the volume ^ (in the considered case of plane deformation, over the area of the element dF). For the convenience of the further solution, we represent equation (5) in matrix form.
I \u003d - | a -e-eG-e 2
G \u003d 2\eTscheG - \u003d
The values of the components of the vector ё = |ё„ ■■■ ё32|| must be such that the potential energy I has a minimum value:
■- = 0 ; H1...3, . (7)
After differentiation, in vector form we get:
And -ING) -e \u003d f. (8)
To understand the notation, ||in||, and ||and|| once again consider a separate element presented in Fig.3.
If it is triangular, as in our case, and the stresses in it change linearly, then it is recommended to relate the displacement values of the element nodes and its deformation by the following formula.
X22 X-32 X11 X31 X32 X12 X21 X11
21 Hz 12 22
We write expression (9) in matrix form as follows:
e = \\B\\ - e. (9 a)
As can be seen from (9) ||in|| expresses changes in the coordinates of the nodes of a triangular element while maintaining its area and connects the displacement in its nodes with the accumulated deformation.
In turn ||and|| expresses the relationship between the strain tensor and the stress tensor. Its values are different for the elastic and plastic states. Output ||And|| for both states
yany can be found in . Here its values are given, and only for plane deformation and the energy approach. Elastic deformation:
1 + V 1- - 2v 1 - 2v
Plastic state:
)- ee = |I| - ee, (12)
for the elastic part of the deformation, for the plastic part of the deformation.
a11 a11 a11 0 22 ^ a11 012
a22 a11" 0 22 0 22 0 22 a12
a12 a11 a12 0 22 a12 012
where shear modulus O =
8 - characteristic parameter of the elastic-plastic state
This parameter makes it possible to take into account the dependence of stresses on deformation and other process parameters, which are expressed through a relation of the form
0 = 0(e, e, T, a in c), (17)
where e is the accumulated strain under uniaxial compression (tension);
e - strain rate; T - temperature;
aoa a, b, c - empirically determined ratios. The search for such relationships is dedicated to
but a lot of research. We have used the results for alloys used in the rolling of GTE rings.
Let us return to formula (8), which, as is now clear, expresses the relationship between the force in the element, on the one hand, and stress, deformation, and displacement, on the other. Eliminating displacements from formula (8), we denote its left side as follows.
W = M-|I-B-dF- (18)
U is the stiffness matrix. It takes into account all the deformation parameters given above. If this matrix is given for one triangular element, it is called local. The global matrix will be the matrix of the right side of the system (M ++1) of equations, formed as the algebraic sum of the local matrices of each element.
It should be noted that we already know the voltage
For a non-driven roll, in the first half of the capture arc, the forces are directed against the direction of metal movement, in the second - in the direction of movement (Fig. 3, b). For each node in contact with the roll, the direction of the forces is known. P - normal pressure, t = juP - friction force, j - coefficient of friction.
Consider equation (19), which in expanded form for node 9 can be written as follows (Fig. 3b).
k17.17 d91 + k17.18 d 92 + k17.19 d101 + k17.20 d102 +
K17.21 d111 + k17.22 d112 = f91 =
JP cos (p3 - P sin (p3, (20)
k18.17 d91 + k18.18 d92 + k18.19 d101 + k18.20 d102 +
K18.21d111 + k18.22d112 = f92 =
P sin (p3 + /uP cos (p3. (21)
When solving equations (20) by the Gauss method, we take into account the condition of non-penetration of the workpiece material into the non-driven roll:
d91 ■ sin (p3 = d92 ■ cos^3. (22)
This condition will allow us to exclude from the system of equations (19) d92 We perform this transformation for all equations containing nodes lying on the surface of the non-driven roll.
On the drive roll, the speed of rotation is known, but the mutual displacement of the surfaces of the metal and the roll is unknown. Let's apply the following method.
Let's introduce a fictitious layer of elements. Let's show it on the example of an element with nodes 7, 6 (Fig. 3a). These nodes move as rigidly connected to the roll. The nodes of the contact layer of metal 5 (Fig. 3 a) move along the surface of the roll. The element stiffness matrix K is modified using the friction index m. The elements of the stiffness matrix are multiplied by m / m - c. At
m tending to 0, the element becomes stiffer, simulating low friction. For m ^ 1, the "sticking" of the material to the rolls is simulated. The elements do not model the lubrication layer, but model the action of the lubrication. Each element of the fictitious layer is created at the time of construction of the corresponding real element. Matrices of real and fictitious elements can be compared and jointly solved in equation (8). The movements of the fictitious nodes are known, i.e. they move as rigidly connected to the roll.
Equations (19) for node 5 (Fig. 3 a) will have the following form.
k9 3d 23 + k 9.4d 22 + k9.7 d41 + k9.8 d42 + k9.9 d51 + + k 9.10 d52 + k 9.15 d 81 + k9.16 d82 + k 9.13 d71 + + k 9.14d 72 + k 9.11 d61 + k 9.12 d62 = f51 , (23)
k10.3 d 21 + k10.4d 22 + k10.7 d41 + k10.8 d42 + k10.9 d51 + + k10.10 d 52 + k10.15 d 81 + k10.16 d 82 + k10.13 d71 + + k10.14d72 + k10.11d61 + k10.12d62 = f52 . (24)
Since the force in node 5 is normal to the roll surface, we have:
f2Cos^2 = fs1sin (Р2, (25)
The condition of non-penetration of the roll surface ds1 cos^2 = ds2 sin (p2, (26)
When compiling the global stiffness matrix, transforming equations (23, 24) taking into account (25,
Rice. Fig. 4. Arrangement of equal-strength inserts in the deformation zone during rolling. H0 is the thickness of the billet before it enters the rolls; y, x - values of insertion coordinates;
a0, b0 and ax, bx
initial and final sizes of inserts, respectively
52, yb1, you can also use
26), excluding /51, /5, is called when solving system (19) by the Gaussian elimination method. During the solution, the values of the accumulated strain, stresses and displacements are found, i.e. the stress-strain state in the deformation zone.
The adequacy of the model is verified on the basis of experimental studies of the rolling of rings given in the work. In this work, we studied the deformation zone of a ring made of aluminum alloy AMg6, in which
holes were drilled in layers and filled with inserts of the same metal (Fig. 4). The rolling of rings with an outer diameter of 400 mm, an inner diameter of 340 mm and a thickness of 30 mm was carried out on a ring rolling mill model PM1200 with work roll diameters: upper drive roll - 550 mm and lower non-drive roll - 200 mm; the maximum feed rate of the pressure device was 16 mm/sec.; the rolling speed provided by the design of the mill corresponded to 1.5 m/sec. According to the results of measuring the inserts, the values were found
"h T| /) / [>
___^ S.GChS1 IG I /1^1111.1С
¿■¡i nt I a
V no|en.nch I data
5vep;rsks t;
anspro-."and that
SgU 1, and inm?
S: h: "ini 2 ^ I member MZDSL.-fEBaMN!
■I l -I l and e. 2 v. I 11 and. 7VSH1 V ■DIM [-1
Rice. Fig. 5. Distribution of strain intensity over the height of the strain zone during rolling of an annular specimen made of AMg6 alloy: e1 is the degree of accumulated strain, y is the coordinates of the point along the y-axis (Moreover, Ho/2 corresponds to 1 on the y-axis)
deformations and stresses, which are presented in fig. 5. The presented experimental data on the rolling of an AMg6 alloy ring were introduced into the developed finite element model. On fig. Figure 5 compares simulation results and experimental data.
As can be seen from the graph, the results of the experiment and simulation are almost identical (the convergence is about 15%).
1. To form a homogeneous macrostructure and the required level of mechanical properties in the annular parts of the GTE, it is necessary to control the amount of the accumulated degree of deformation at each stage of the hot rolling of the billet.
2. A finite element model has been developed
the ratio of the degree of accumulated deformation at various stages of deformation of ring blanks.
3. Comparison of the simulation results and experimental dependencies confirms the adequacy of the model.
BIBLIOGRAPHY
1. Lakhtin Yu.M., Leontieva V.P. Metal science. M.: Mashinostroenie, 1980. 493 p.
3. Tselikov A.I. The theory of force calculation in rolling mills. - M.: Metallurgizdat, 1962.
2. Finite-element plasticity and metalforming analysis / G.W. Rove., C.E.N. Sturgess, P. Hartly., Cambridge University Press, 2005. 296 pp.
4 P.I. Polukhin, G.Ya Gun, A.M. Galkin Resistance to plastic deformation of metals and alloys. , M. Metallurgy, 1983, p. 353
5 Kostyshev V.A., Shitarev I.L. Ring rolling. - Samara: SGAU, 2000. S. 206.
THE FINAL-ELEMENT MODEL CALCULATION SIZE SAVED DEFORMATION IN THE PROCESS OF HOT ROLLING RINGS
© 2009 F.V. Grechnikov1, E.V. Aryshensky1, E.D. Beglov2
It is developed, is a final-element model of calculation degree the saved up deformation at various stages of deformation of ring preparation. Comparison of results of modeling and experimental dependences confirms adequacy of model.
Key words: rolling rings, macrostructure, recrystallization, the saved up deformation, method of final elements, model, a rigidity matrix, full-strength inserts.
Fedor Grechnikov, Doctor of Technics, Professor, Corresponding Member of Russian Academy of Sciences, Vice Rector for Academic Affairs. Email: [email protected] Evgenie Aryshensky, Graduate Student. Email: [email protected]
Erkin Beglov, Candidate of Technics, Leading Engineer. Email: [email protected]
Bending on GGM used for the manufacture of forgings that require a significant stamping space and a large stroke of the slider. In order for bending to end at the lower limit of forging temperatures (800–850°C), the workpieces are heated to 900–1000°C (higher heating temperatures are undesirable, since deviations of the forging dimensions from the specified ones increase at the bending points). A long workpiece is not heated along its entire length, but only the sections located in the bending zone and adjacent to this zone. Bending in dies is finished with editing, and sometimes with calibration.
Rolling is carried out on forging rolls for shaping blanks for subsequent stamping on other stamping units. During the rolling process, the cross section of the workpiece decreases (but it should not be less than the maximum cross section of the product), and its length increases; in this case, a product with different sections along the length is obtained.
Depending on the complexity of the shape, rolling can be single or multi-pass. Accordingly, the rolls can have single or multi-strand inserts installed in single-stand rolls. Stamping in them can be performed without turning or with turning by 90° after each transition. In multi-cage rolls, rolling is carried out without turning over the pass. So, at the Volga Automobile Plant, the preparation of semi-axle blanks preheated in an inductor before stamping on the GCF is performed on nine-stand rollers operating in automatic mode. Rolling is also successfully used for stamping forgings from a bar with flash formation. The forgings emerging from the rollers are interconnected by a common flash. During the subsequent trimming of the flash, the forgings are separated.
Rice. 7.6.
For hot rolling performed on ring rolling machines (Fig. 7.6), ring-shaped blanks are used. The billet 1 is rolled between the pressure 4 and the central 3 rolls. Roll 4 is driven and presses on the workpiece, due to which it acquires the required cross-sectional shape and diameter. Roll 5 is the guide roll, and roll 2 is the control roll. When the forging being rolled comes into contact with roll 2, the latter begins to rotate, the pressure roll moves back to its original position, and rolling ends. The shape of the cross section of the wall of the rolled ring can be varied and is determined by the profile of the rolls.
Rice. 7.7.
Method hot rolling teeth gears are made from a pre-treated workpiece, which is heated in an inductor to the required depth and to the required temperature. During piece machining of wheels (Fig. 7.7), the heated workpiece 2 is clamped on the mandrel with rings 3 and rotating rolls 1 and 4 with teeth are brought to it: as a result, the workpiece begins to rotate, and teeth form on it. Rolls 1 and 4 are provided with collars 5 at the ends, which limit the movement of metal along the tooth. The knurling performance with the best gear quality is about 50 times higher than the performance of rough gear cutting.
For high speed hot forging in closed dies, high-speed hammers are used with a deformation speed of 18–20 m/s, at which contact friction forces decrease, the contact time of the workpiece with the tool decreases, as a result of which the heat released during plastic deformation (thermal effect) does not dissipate, but remains in workpiece and raises its temperature. These factors contribute to an increase in the ductility of the metal, as a result of which low-plasticity metals and alloys, such as tungsten, can be processed on high-speed hammers: high-speed steels, titanium alloys, etc.
Rice. 7.8. Scheme of isothermal stamping with stacking of workpieces: a - before stamping, b - after stamping; 1, 4, 7, 10 - dies, 2, 5, 8, 11 - blanks, 3, 6, 9, 12 - punches, 13 - press slider, 14 - container, 15 - heater, 16 - heat-insulating material, 17 - casing
Isothermal stamping(Fig. 7.8) is carried out at a practically constant temperature of special steels and alloys with a narrow temperature processing interval (for example, 30-50 ° C for some heat-resistant alloys). The stamp for such stamping is made of heat-resistant materials and installed in an induction heater or resistance heater, which ensures the same temperature of the workpiece and die inserts.
Under isothermal conditions, it becomes possible to use the effect of "superplasticity", i.e., the ability of some metals and alloys to sharply reduce the resistance to deformation and increase plasticity with a decrease in the rate of deformation.
Great prospects have been introduced into the machine-building industry and, in particular, into the forging and stamping production of the method cross-wedge rolling of stepped billetsØ 10-250 mm and up to 2500 mm long, intended for subsequent hot die forging, for example, forgings of a connecting rod of an automobile engine, which eliminates the need for blank transitions.
For rolling, rods made of carbon and tool steels, as well as a number of heat-resistant and non-ferrous alloys, are used. Cross-wedge rolling lends itself well to full automation, increases labor productivity by 5-10 times in comparison with forging and turning on automatic lathes, reduces metal consumption by 20-30% and reduces the cost of products.
Rice. 7.9. Schemes of cross-wedge rolling using roll (a), flat (b) and roll-segment (c) tools
In the process of cross-wedge rolling, a round billet, the diameter of which is equal to or greater than the maximum diameter of the product, is deformed with a reduction ratio of 1.1-3 by two rolls or plates with wedge elements on the surface (Fig. 7.9).
During rolling on two-roll mills, the billet is held in the deformation zone by means of guide rulers located along the inter-roll space, or bushings located at the ends of the rolls. Machine tools with flat tools have flat plates with protruding wedges instead of rotating rolls. On roll-segment mills, blanks are shaped by moving a convex and concave wedge tool towards each other. The convex tool is mounted on a rotating roll, the concave tool is mounted on a fixed segment.
The end rolling method makes it possible to produce forgings from alloyed and non-alloyed steels weighing from 0.5 to 150 kilograms, with a diameter of up to 1000 mm. The configuration of blanks is as close as possible to the configuration of finished products. Machining allowance is no more than 5 mm. The current modern technology makes it possible to obtain forgings with a variety of configurations and having a structure and properties that ensure their use in the most difficult loading conditions, the service characteristics of products in terms of fatigue strength increase from 1.5 to 6 times. Metal is saved, labor intensity is reduced, and quality is improved and operational reliability of products. The blanks after forging by rolling fully correspond to the term "precise blanks of parts".
Induction heating METHOD FOR END ROLLING OF FORGINGS BY THE END ROLLING OF THE "BODY OF REVOLUTION"
The process of manufacturing the product goes through a multi-stage research preparation. To assess the quality of the material, preliminary tests are carried out. In the course of studying the terms of reference, it is taken into account where this product will be used, what technological processing it will be used for. Drawings, design documentation undergo a series of control approvals with the customer, and only after that prototypes are made. It is impossible to achieve high quality products in mass production, when the order volume can reach up to 2,000 -3,000 pieces of forgings, without careful preparation of production and well-developed technology. For the development of each new product, our approach is exclusively professional.
The products of Gefest-Mash LLC are produced under controlled conditions established by the Quality Management Certification System that meets the requirements of GOST ISO 9001-2011 (ISO 9001:2008), registration number ROSS RU. 0001.13IF22.
At present, the following types of forgings have been mastered
Sleeve Piston core Valve plate Pin
Pump bushing to China st.70 (IMPORT SUBSTITUTION) Pump bushing 8T650 st.70 (IMPORT SUBSTITUTION) t.70 Gear block st.40X Gear block 2 st.40X Gear block 3 st.40X
Ring st.40X Plate st.20KhGNM Step gear st.40X Flange made of st.12X18H10T Electric generator drive ring hub st.
Gas pipeline flange (РH16-160) st.40X, 09G2S, 20 BRS connection st.45 Hollow shaft (Sleeve) Railway st.45 Valve plate st.40khn2ma Pump piston core st.40X
Axial fan flange Piston core 2 Fan hub st Washers for gas pipelines st.40X Rolling stock fan hub Railway
1. STATE OF THE QUESTION AND FORMULATION OF RESEARCH PROBLEMS.
1.1 Applications of ring products in modern industry
1.2 The main methods of manufacturing aircraft GTE rings.
1.3 Experimental methods for studying the deformation zone.
1.4 Analytical methods for studying the deformation zone during rolling and rolling.
1.5 Application of the finite element method to study the deformation zone during rolling and rolling.33.
1.6 Brief description of KhN68VMTYUK-VD and KhN45VMTYuBR-ID alloys and the mechanism of their recrystallization.
1.7 Review of studies of the thermal state of the metal in the deformation zone during ring rolling and flat rolling.
2. DETERMINATION OF THE DEPENDENCE OF THE FRACTION OF THE RECRYSTALLIZED VOLUME ON THE TEMPERATURE OF THE DEGREE OF DEFORMATION AND THE TIME OF THE INTERDEFORMATION PAUSE FOR ALLOYS KhN68VMTYUK-VD AND
KhN45VMTYuBR-ID.
2.1 Analysis of the mechanism of shaping during hot rolling of GTE rings.
2.2 Goals and methodology of the experiment.
2.3 Equipment and instruments for research.
2.4 Study of the process of primary recrystallization in KhN68VMTYUK-VD and KhN45VMTYuBR-ID alloys after hot deformation.
3. DEVELOPMENT OF A MATHEMATICAL MODEL OF THE PROCESS OF HOT ROLLING OF GTE RING PARTS.
3.1 Basic assumptions and hypotheses.
3.2 Mathematical description and discretization of the solution area.
3.3. Approximation of displacement, strain and stress fields.
3.3.1 Approximation of displacements in an element.
3.4. Compilation of local global stiffness matrices. The main system of equations of the finite element method.
3.4.1 Construction of a local stiffness matrix.
3.4.2 Building a global stiffness matrix.
3.4.3 Accounting for boundary conditions.
3.5. Building a temperature field model.
3.6. General structure of the mathematical model.
4. INVESTIGATION OF THE INFLUENCE OF INTERDEFORMATIONAL PAUSES ON THE VALUE OF ACCUMULATED STRAIN AND TEMPERATURE DURING ROLLING GTE RINGS.
4.1 Description of the stages of rolling of GTE rings.
4.2 Search for optimal reduction modes and the duration of the interdeformation pause during hot rolling of GTE rings.
4.3 Comparison of simulation results with experimental data.
4.4 Checking the found results with a thermal imager
4.5. Industrial study of ring rolling modes with regulation of the interdeformation pause.
5 SEARCH FOR OPTIMAL MODES OF LOCAL COMPRESSIONS AND SPEEDS OF THE DEFORMING TOOL DURING ROLLING GTE RINGS.
5.1 Determining the allowable deformation time.
5.2 Selection of the optimal rotation speed and local reductions.
Recommended list of dissertations
Optimization of technological regimes of deformation of large-sized ring blanks from hard-to-deform heat-resistant steels and alloys 1999, Candidate of Technical Sciences Mints, Alexander Ilyich
Development of a highly efficient resource-saving technology for the production of rings from heat-resistant alloys based on the study of the upsetting process of workpieces 2013, candidate of technical sciences Batyaev, Daniil Vladimirovich
Optimal control of a non-stationary object with distributed parameters and moving action 1999, candidate of technical sciences Chuguev, Igor Vladimirovich
Research, development of equipment and mastering the technology of cold rolling of bearing rings 1998, candidate of technical sciences Kishkin, Ivan Vasilyevich
Simulation of the deformability of continuously cast steel in order to improve the rolling of billets 1999, candidate of technical sciences Antoshechkin, Boris Mikhailovich
Introduction to the thesis (part of the abstract) on the topic "Development of a methodology for calculating the accumulated deformation during hot rolling of GTE rings, taking into account interdeformation pauses"
Relevance of the topic. Gas turbine engines (GTEs) are widely used in aircraft and gas pumping stations. Today, the level of competition is high in domestic and foreign engine building. Therefore, enterprises engaged in the production of gas turbine engines strive to ensure that their products meet the highest requirements for the most important performance characteristics. The operational reliability and other important parameters of a gas turbine engine depend mainly on how high-quality the parts of its components are.
One of the most important parts in engine building are GTE rings that serve as connecting elements. The failure of at least one ring can lead to a breakdown of the entire engine, i.e. an emergency. Therefore, the annular parts of aircraft gas turbine engines operating at high temperatures and dynamic loads are subject to high requirements for structural uniformity and the level of mechanical properties. One of the main ways to obtain ring parts is hot rolling from a forged billet. A characteristic disadvantage of this process is the appearance in the annular part during the final heat treatment of areas with large grains, which are the result of the metal obtaining critical values of the degree of plastic deformation. The uneven-grained structure of the ring, in turn, leads to a sharp decrease in the level of mechanical properties and the service life of these parts under difficult operating conditions.
The appearance of zones with large grains in the annular blank is facilitated by the fragmentation of deformation during rolling. In fact, ring rolling is a set of local deformation acts in which hardening occurs. Between these local acts, an interdeformation pause occurs in which partial recrystallization is observed and strain hardening is removed. A decrease in the degree of strain hardening, in turn, contributes to the formation of zones with large grains during the final heat treatment of the ring.
The purpose of this work is to improve the technological modes of hot rolling of GTE annular parts based on the developed finite element model for calculating the accumulated deformation, taking into account the temperature and speed parameters of deformation, the duration and number of interdeformation pauses
To achieve this goal, it is necessary to solve the following tasks:
1. Determine the dependences of the change in the proportion of the recrystallized volume of the ring billet on the heating temperature, the degree of deformation and the time of the interdeformation pause for KhN68VMTYUK-VD and KhN45VMTYuBR-ID alloys (typical materials for GTE rings).
2. Develop a finite element model for calculating the values of the degree of deformation accumulated during the rolling process, taking into account the heating temperature of the workpiece, the magnitude of local reductions and the duration of each interdeformation pause.
3. On the basis of the developed mathematical model, to investigate the influence of the billet heating temperature, the magnitude of local reductions, the duration and number of interdeformation pauses on the degree of accumulated deformation over the entire rolling cycle.
4. To develop recommendations on the choice of temperature-speed and deformation modes of hot rolling, the number and duration of interdeformation pauses, providing the calculated values of the accumulated deformation, the homogeneity of the macrostructure and the required level of mechanical properties of ring blanks.
5. Conduct a pilot test of the adequacy of the developed technological modes of hot rolling of ring parts to the requirements for the macrostructure and the level of mechanical properties.
The scientific novelty of the work is as follows:
1. The process of hot rolling of GTE rings is considered as a process with fractional deformation, consisting of multiple local compressions and subsequent multiple acts of partial recrystallization in interdeformation pauses.
2. A finite element model has been built that allows to investigate the hot rolling of ring blanks, taking into account the heating temperature of the metal, the degree of local reductions and the duration of interdeformation pauses.
3. The dependences of the change in the proportion of the recrystallized volume of the ring billet made of KhN6 8VMTYuK-VD and KhN45VMTYuBR-ID alloys (typical materials for GTE rings) on the heating temperature, the degree of deformation, and the time of the interdeformation pause are established.
4. Using the ThermaCAM P65 thermal imager, the thermal field was studied during the rolling of GTE rings and the optimal duration of the deformation process was established.
The reliability of the scientific results of the research is confirmed by the use of the most accurate and modern method of studying plastic media (finite element method) for modeling, the use of a software product in the modern C + language for the implementation of the model, as well as a wide range of experimental studies.
Research methods. Studies of the stress-strain state during the rolling of GTE rings were carried out using a finite element model, on the basis of which a software product in the C + language was created. Experimental studies included the upsetting and etching of samples from KhN68VMTYuK-VD and KhN45VMTYuBR-ID alloys and the study of their macrostructure using an Axiovert 40 MAT instrument. The experimental rolling of the ring was carried out on a PM1200 rolling machine, followed by cutting out samples from the ring blank and studying the mechanical properties on a TsTSMU 30 stretching machine and macrostructure using an Axiovert 40 MAT device. The temperature field was studied using a ThermaCAM P65 thermal imager.
The author defends a finite element mathematical model that allows one to analyze the process of rolling out of GTE rings, taking into account the fractional deformation. Established patterns of change in the proportion of recrystallized volume on temperature, degree of deformation and time of the interdeformation pause for alloys KhN68VMTYUK-VD, KhN45VMTYuBR-ID. Distribution of local reductions and speed of rotation of the drive roll during the rolling of the GTE rings, providing the specified values of the degree of accumulated deformation. Experimental studies of the thermal field, deformable annular workpiece.
The practical value of the work.
1. On the basis of the developed mathematical model, the problem of determining the values of the degree of deformation accumulated over the entire rolling cycle, depending on the specific process parameters, was solved, which makes it possible to ensure its optimal values before the final heat treatment.
2. Recommendations have been developed for choosing the optimal temperature and speed modes for local reductions of the annular billet, taking into account the feed rate and speed of rotation of the drive roll, which ensure the uniformity of the structure and high mechanical properties.
3. The results obtained in the dissertation were used in OJSC "Motorostroitel" and OJSC SNTK "NES Engines" named after. N.D. Kuznetsov during the development of technology for hot rolling of ring blanks from KhN68VMTYUK-VD and KhN45VMTYuBR-ID alloys
Approbation of work. The main results of the work were reported and discussed at the following conferences: Royal Readings (Samara, 2007), All-Russian Scientific and Technical Conference of Students "Student Spring 2008: Engineering Technologies" (Moscow, 2008), Reshetnev Readings (Krasnoyarsk, 2008). International Scientific and Technical Conference "Metal Physics, Mechanics of Materials, Nanostructures and Deformation Processes" (Samara, 2009) Publications. 6 papers have been published on the topic of the dissertation, including 2 articles in leading peer-reviewed journals and publications recommended by the Higher Attestation Commission.
Structure and scope of work. The dissertation work consists of an introduction, four chapters, main results and conclusions, a bibliography of 133 titles, contains 138 pages of typewritten text, 58 figures, 3 tables.
Similar theses in the specialty "Technologies and machines for pressure treatment", 05.03.05 VAK code
Research, development and implementation of effective technologies for the production of strips and strips from steel and non-ferrous metal alloys with desired structure and properties 2011, Doctor of Technical Sciences Aldunin, Anatoly Vasilyevich
Improving the technology of manufacturing rings from titanium alloy VT6 by determining rational deformation modes 2017, Candidate of Technical Sciences Alimov, Artem Igorevich
Establishment of the features of hot rolling of large-sized ingots from complexly alloyed copper alloys in order to improve the quality of strips 2003, candidate of technical sciences Shimanaev, Alexander Evgenievich
Mathematical modeling and optimization of materials deformation processes during pressure treatment 2007, Doctor of Physical and Mathematical Sciences Logashina, Irina Valentinovna
Technological process of hardening semi-hot thermomechanical treatment during forging stamping 2013, Ph.D. Fomin, Dmitry Yurievich
Dissertation conclusion on the topic "Technologies and machines for pressure treatment", Aryshensky, Evgeny Vladimirovich
MAIN RESULTS AND CONCLUSIONS
1. A mathematical finite element model has been developed for hot rolling of GTE rings, taking into account the fractional nature of deformation, which makes it possible to determine the temperature of the workpiece, the degree of accumulated deformation and take into account the influence of local reductions and interdeformation pauses on these parameters.
2. Regularities have been established for the change in the proportion of the recrystallized volume of the ring billet depending on the rolling temperature, the degree of deformation and the duration of the interdeformation pause for KhN68VMTYUK-VD and KhN45VMTYuBR-ID alloys.
3. At each stage of shaping, the values of the heating temperature, the degree of local reductions, and the duration of the interdeformation pauses necessary to obtain the calculated value of the accumulated deformation in the annular workpiece before the final heat treatment are established.
4. Comparison of the data obtained by modeling and experimentally shows high convergence and confirms the adequacy of the developed finite element model.
5. In general, on the basis of meta-mathematical modeling, science-based technological modes of hot rolling have been developed with regulated values of the deformation temperature, rotation speed and drive roll feed rate, ensuring the homogeneity of the macrostructure and increasing the strength properties of the annular parts of the gas turbine engine by 8 - 10% and plastic by 15 - 21%.
6. Due to the increase in the reliability and durability of the annular parts of the GTE during the operation of the NK-32 engine, the total economic effect of the implementation amounted to 1,000,000 million rubles for each engine
List of references for dissertation research Candidate of Technical Sciences Aryshensky, Evgeny Vladimirovich, 2009
1. Kostyshev, V.A. Methods of shaping of profile ring blanks by rolling / V.A. Kostyshev, F.V. Grechnikov, - Samara: Samar Publishing House. state aerocosm, un-ta, 2007 71 e.
2. Kostyshev, V.A. Ring rolling / V.A. Kostyshev, I.L Shitarev. Samara: Samar Publishing House. state aerospace, un-ta, 2006 - 207 e.
3. Alekseev, Yu.N. Investigation of the state during rotational extrusion of bimetallic shells / Yu.N. Alekseev // Aircraft building. Air tech. fleet. Rep. interdepartmental thematic scientific and technical collection 1976. No. 39. pp. 57-62.
4. Barkaya, V.F. To the theory of calculation of forces and accuracy of rotational shaping processes / V.F. Barkaya // Proceedings of the Georgian Polytechnic Institute. 1975. No. 1. C 173-177.
5. Shepelev, I.N. Production of ring blanks from die sheet and heat-resistant alloys on a spinning 195 installation with heating of the deformation zone / I.N. Shepelev, G.N. Proskuryakov // Aviation industry. 1975. No. 3. pp. 60-63.
6. Bogoyavlensky, K. N. Fabrication of thin-walled profiles from titanium and its alloys on a profile bending mill / K. N. Bogoyavlensky, A. K. Grigoriev // Processing of metals by pressure. Proceedings of LPI. M.-L.: Mashgiz, 1963. - Issue. 222 f. - S. 148-150.
7. Proskuryakov, G.V. Restricted bend / G.V. Proskuryakov // Aviation industry. 1966. No. 2. pp. 9-13.
8. Ershov, V.I. To the calculation of the processes of forming under the action of several loads / V.I. Ershov II Proceedings of Kazan, aviation. in-ta. Aviation technology. 1980. No. 2. pp. 103-107.
9. Naidenov, M.P. Fundamentals of calculation of power parameters of tangential processing of tubular blanks using the theory of dimensions / M.P. Naidenov // Processing of metals by pressure in mechanical engineering. 1974. No. 12. pp. 8-16.
10. Nazartsev, N.I., Svitov, B.V. Development of technology for manufacturing seamless cylindrical thin-walled shells by rolling / N.I. Nazartsev, B.V. Svitov // Steels and alloys of non-ferrous metals. Kuibyshev. 1974. S. 84-92.
11. P. Ershov, V.I. Analysis of two methods of local deformation / V.I. Ershov // Proceedings of Kazan, aviation. in-ta. Aviation technology. 1981. No. 1. pp. 87-92.
12. Kolganov, I. M., Proskuryakov G. V. Study of the process of shaping profiles by constrained bending in a tool die. - Tolyatti, 1979. 9 p.
13. Zinoviev, V.N. Research and improvement of the process of rolling rings from titanium alloys: Abstract of Cand. diss. M, 1977. 16 p.
14. Kostyshev, V.A. Study of the technological process of manufacturing rolled thin-walled seamless profile rings for aircraft engines: Cand. diss. Kuibyshev, 1982. 219 p.
15. Mikhailov, K.N. The main tasks of science and industry in the development of rolling processes / K.N. Mikhailov, M.S. Sirotinsky // VILS Scientific and Technical Bulletin: Technology of Light Alloys. 1973 No. 11. pp. 9-10.
16. Zuev, G.I. Hot rolling of profile ring parts / G.I. Zuev,
17. A.I. Murzov, V.A. Kostyshev, B.C. Samokhvalov. // Aluminum alloys and special materials. Proceedings of VIAM. 1975. No. 9. pp. 157-162.
18. Murzov, A.I. Rolling titanium seamless complex profile rings / A.I. Murzov, V.A. Kostyshev, G.I. Zuev, A.A. Chuloshnikov // Aluminum alloys and special materials. Proceedings of VIAM. 1977. No. 10. pp. 155-160.
19. Murzov, A.I. Production of seamless U-shaped rings from heat-resistant alloys according to a new rolling pattern / A.I. Murzov, G.I. Zuev,
20. V.A. Kostyshev, F.I. Khasanshin, V.S. Samokhvalov // Aluminum alloys and special materials. Proceedings of VIAM. 1977. No. 10. pp. 160-165.
21. Panin, V.G. Profiling of ring blanks during hot rolling / V.G. Panin, A.N., Buratov // Information and Technical Bulletin: -Kuibyshev, 1988 No. 12. -S.6.
22. Panin, V.G. Production of profile ring blanks on rolling machines / V.G. Panin, A.N., Buratov // Information and Technical Bulletin: Kuibyshev, 1989 - No. 3. -S.2.
23. Kiselenko, I.A. Rolling out flanged ring blanks of GTE / I.A. Kiselenko, I.L. Shitarev, A.N. Chikulaev // Rolling of GTE ring billets // Aviation industry. 1988. - No. 7 - S. 13 - 14.
24. Zinoviev, V.N. Possibilities of rolling titanium rings with high mechanical properties on the KPS-2000 mill. / V.N., Zinoviev, L.N. Ivankina // Production of titanium alloys. VILS. 1975. No. 7. S. 283288.
25. Panin, V.G. Influence of deformation conditions on the filling of calibers during rolling and methods of shaping ring blanks for gas turbine engines / V.G. Panin, A.N. Butrov // Aviation industry. 1989. - No. 11 - S.20-22.
26. Panin, V.G. Influence of the dimensions of the ring profile and the thickness of the original workpiece on the filling index of the caliber / V.G. Panin, A.N., Buratov, G.F. // Information and technical bulletin: Kuibyshev, 1989 - No. 10. -p.4.
27. Polukhin, P.I. Production of billets by ring rolling. / P.I. Polukhin // News of universities. Ferrous metallurgy 1970 No. 11. S. 16 -19.
28. Solovtsev, S.S. Form change of ring blanks during hot rolling with a T-shaped cross section / S.S. Solovtsev, M.Ya. Alypits // Forging and stamping production. 1970. No. 2. pp. 1-4.
29. Rabinovich, JI.A. Production of seamless ring blanks by machine rolling / L.A. Rabinovich // Production and technical bulletin. 1971. No. 10. pp. 6-9.
30. Papin, V.G. Kinematic relations when rolling rings of rectangular section / V.V. Papin // Proceedings of the Leningrad Polytechnic Institute. 1970. No. 315. pp. 105-109
31. Bogoyavlensky, K.N. Cold rolling of ring parts / K.N. Bogoyavlensky, V.V. Lapin // Forging and stamping production. 1973. No. 2. pp. 18-22.
32. Davydov Yu.D. Designing a drawing of a rolling ring forging using a computer / Yu.D. Davydov // Forging and stamping production. 1969. No. 11. C, 9-11.
33. Vieregge. G. Gestaltung einer Riugschmiede under besonderer Berucksichligung des Rmgwalzverfahrens./ G. Vieregge. // Stahl imd Eisen, 1971, 91. No. 10, pp. 563-572.
34. Kazantsev, V.P. Stamping of an accurate workpiece for rolling rings / V.P. Kazantsev, V.V. Novichev // Technology of light alloys. 1975. No. 12. pp. 80-81.
35. The formation of a tightening during the rolling of shaped rings. ""Int. J.Mech. Sei." 1975, 17, No. 11-12, pp. 669-672. RJ 14V, 1976, 6V64.
36. Rozhdestvensky, Yu.L. Peculiarities of Form Change in Hot Closed Rolling of Billets of Rings and Radial Ball Bearings / Yu.L. Rozhdestvensky, G.P. Ostroushin // Proceedings of the VNIIP Institute. 1967 no. 38-40.
37. Sidorenko, B.N. Technological features of manufacturing ring parts by rolling / B.N. Sidorenko, B.F. Savchenko // Technology and organization of production. 1973. No. 3. pp. 38-41.
38. Shchevchenko L.N., Doroshevich A.G. Obtaining ring blanks from alloy D16 by radial rolling / L.N. Shchevchenko, A.G. Doroshevich // Production and technical bulletin. 1975. No. 6. S. 2425.
39. Pressure on the rolls and torque during the rolling of the rings. "Int. J. Mech. Sei" 1973, 11, 15, No. 11, p. 873-893.
40. Ring rolling at the Woodhouse and Rixson plant. Ring rolling at Woodhouse and Rixson. "Met and Metal Form.," 1973, 40, no. 8, p. 233. Ref.: RJ Metallurgy, 1974, 2D79.
41. Papin, V.G. Hot deformation of KhN65VMBYU-ID alloy on rolling machines / V.G. Papin, V.A. Kostyshev // Information and technical bulletin: Kuibyshev, 1988 - No. 11. -S.2.
42. Kostyshev V.A. Stress state in the deformation zone during the rolling of aircraft engine rings, taking into account the theory of anisotropic media: / V.A. Kostyshev // Collection of SSAU. Samara, 1997. S. 57-63.
43. Weber K.N. "Stahl und Eisen", 1959, Bd 79, Nr. 26, pp. 1912-1923.
44. Node, T., lamato H. "Sumitomo Metals", 1976, a: 28, no. 1, pp. 87-93.
45. Kotelnikova L.G. Production of precision blanks of machine-building parts by rolling. / L.P. Kotelnikova, G.G. Shalinov // M.: VNIINFORMTYAZHMASH, 1968. S. 155-203.
46. Johnson W., Hawkard J.B. "Metallurgia und Metal Forming", 1976, v. 43, no. 1, pp. 4-11. (EI.TOKP, No. 19, 1976.)
48. Moderne Ringproduktion auf Banning HV Rmgwalzmaschinen. Vortrag. Sklirmedeausrustungkongress "Forming Equipment Symposium", US-Forging Industry Association. Chicago. 1973, pp. 104-108.
49. Lapin V.V., Fomichev A.F. Investigation of shape change during rolling of rings of rectangular section / V.V. Lapin, A.F. Fomichev. // Proceedings of the Leningrad Polytechnic Institute. 1969. No. 308. pp. 144-148.
50 Winship J.T. Cold ring-rolling warms up Amer. / J.T. Winship Mach., 1976, 20, No. I, pp. 110-113 (EI. TOKP, No. 20, 1976.)
51. Neuveau lammoir automatique a anneaux. "Metaux deformation." 1979, no. 52, pp. 31-36 (EI. TOKP, No. 9, 1980.)
52. Hawkyaid J.B., Ingham P.M. An investigation into profile ring rolling. / J.B. Hawkyaid, P.M. Ingham // "Proc. 1st. Int. Conf. Rotary Metahvork. Process., London, 1979." Kempston, 1979, pp. 309, 311-320 (EI. TOKP, No. 40, 1980.)
53. Yang, H. Role of friction in cold ring rolling. / H. Yang L. G. Guo, // Journal of Materials Science & Technology,. 21 (6) (2005) pp 914-920/
54. Hot rolling of steel rings and shells / B.I. Medovar // K.: Nauk, Dumka, 1993.-240 p.
55. Guo, lg Simulation for guide roll in 3D-FE analysis of cold ring-rolling, / lg Guo, H. Yang, M. Zhan, Mater. sci. Forum 471-472 (2004), pp 99-110.
56. Alfozan, Adel. Design of profile ring rolling by backward simulation using upper bound element technique (UBET) / Adel. Alfozan; Jay S. Gunasekera // 2002, vol. 4, n 2, pp. 97-108 12 page(s) (article). (39 ref.)
57. Ranatunga, V., "Modeling of Profile Ring Rolling with Upper Bound Elemental Technique" Ph.D. Dissertation, Ohio University, 2002.
58 Guo, Lianggang. Research on plastic deformation behavior in cold ring rolling by FEM numerical simulation / Lianggang Guo, He Yang and Mei Zhan// 2005 Modeling Simul. mater. sci. Eng. 13 1029-1046.
59. Abramova, N. Yu. Fabrication and Study of Roll-Forged Rings with Controlled Structure from Imported Nickel Alloys / N. Yu. Abramova, N. M. Ryabykin, Yu. V. Protsiv // Metal Science and Heat Treatment, 2002. - Vol. 41. No. 9 -10. - p. 446-447.
60. Avadhani, G. S. Optimization of process parameters for the manufacturing of rocket casings: A study using processing maps / G. S. Avadhani // Journal of Materials Engineering and Performance, 2003. - Vol. 12. No. 6. - P 609 - 622.
61. WANG, Min. Dynamic explicit FE modeling of hot ring rolling process / Min. WANG, He Zhi-chao YANG, Liang-gang GUO, Xin-zhe OU // Trans. Nonferrous Met. soc. China Vol.16 No. 6 (Sum. 75) Dec.2006
62. Stanistree T.F. The design of a flexible model ring rolling machine / T.F. Stanistreet, J.M. Allwood, A.M. Willoughby // Volume 177, Issues 1-3, 3 July 2006, Pages 630-633
63. Ingo Tiedemann. Material flow determination for radial flexible profile ring rolling / Ingo Tiedemann, Gerhard Hirt, Reiner Kopp, Dennis Mich, Nastaran Khanjari // Springer Berlin / Heidelberg Volume 1, Number 3 / November 2007 pp. 227-232.
64. Kang, B. Kobayashi, S. "Preform Design in Ring Rolling Processes by the Three-Dimensional Finite Element Method," / B. Kang, S. Kobayash International Journal of Machine Tools & Manufacture (v30, 1991), pp. 139151.
65. Kluge, A. "Control of Strain and Temperature Distribution in the Ring Rolling Process," / A. Kluge, Y. Lee, H. Wiegels, and R. KOPP // Journal of Materials Processing Technology (v45, 1994), p. 137.
66. Hua L. The extremum parameters in ring rolling / L. Hua ; Z.Z. Zhao // Journal of Materials Processing Technology, Volume 69, Number 1, September 1997, pp. 273-276(4)
67. Panin, V.G. Development and implementation of shaping methods for hot rolling of economical flanged ring blanks for gas turbine engines: Cand. diss. Samara, 1998. 218 p.
68. Yang, D. Y,. Simulation of T-section profile ring rolling by 3D rigid plastic Finite Element Method / D.Y. Yang, U Kim, JB D Hawkyard, Int. J. Mech. sci. Vol 33, No 7, pp 541-550. 1991
69. Coupu J. Investigation of hot ring rolling using 3D finite element simulation D. Modeling of Metal Rolling Processes. / J. Coupu, J.L. Raulin., J. Huez //. London, 1999
70. Ilyin, M.M. Production of solid-rolled rings and blanks / M.M. Ilyin // M.: Oborongiz, 1957. 126 p.
71. Kostyshev, V.A. Development of scientifically substantiated methods for forming thin-walled profile rings of aircraft engines. Doc. diss. Samara, 1998. - 307 p.
72. Hollenberg A., Bemerkunden zu den Vorgangen bein Walzen von Eisens, St. u. E., 1883, no. 2, pp. 121-122.
73. Smirnov, B.C. Theory of metal forming. / B.C. Smirnov // M: Metallurgy. 1973. 496 s
74. Irinks W, The Biasi Fumav and Steel Plaut, 1915. 220 p.
75. Tarnovsky, I.Ya. Deformation of metal during rolling. / I.Ya. Tarnovsky, JI.A. Pozdeev, V.B. Lyashkov M: // Metallurgizdat, 1956. 287
76. Muzalevsky, O.T. Strain rate distribution in the compression zone during rolling. / O.T. Muzalevsky // Engineering methods for calculating technological processes of metal forming. M.: Metallurgizdat, 1964. S. 228-234.
77. Storozhev M.V., Theory of metal forming. / M.V. Storozhev, E.A. Popov // M.: Mashinostroenie, 1971. 424p.
78. Tretyakov, A.V. Mechanical properties of metals and alloys during pressure treatment. / A.V. Tretyakov, V.I. Zyuzin // M.: Metallurgiya, 1973. 224 p.
79. Siebel. E. "Kraft und materialflub bei der bildsamen formanderung." / E. Siebel. // 1923 Stahl Eisen 45(3 7): 1563
80. Von Karman. "Bietrag zur theorie des walzvorganges." / Karman Von // 1925 Z. angewMath. Mech5: 1563.
81. Ekelund. S. "The analysis of factors influencing rolling pressure and power consumption in the hot rolling of steels." / S. Ekelund // 1933 Steel93(8): 27.
82. Wusatowski Z. Fundamentals of rolling / Z. Wusatowski // 1969 Pergamon.
83 E. Siebel and W. Lueg. Mitteilungen aus dem Kaiser Wilhelm. Institut Fur Eisenforschung, Dusseldorf.
84. E. Orowan. "The calculation of roll pressure in hot and cold flat rolling." / Orowan E. // 1943 Proc. Institute of Mechanical Engineers 150: 140
85. Rudkins. N. "Mathematical modeling of set-up in hot strip rolling of high strength steels." / N. Rudkins, P. Evans // 1998 Journal of Material Processing Technology 80 81: 320 -324.
86. Smirnov B.C. Theory of metal forming. / B.C. Smirnov // M: Metallurgy. 1973. 496 p.
87. R. Shida. "Rolling load and torque in cold rolling." / Shida, R. Awazuhara, H. // 1973 Journal of Japan Society Technological Plasicity 14(147): 267.
88. J. G. Lenard. Study of the predictive capabilities of mathematical models of flat rolling. / J. G. Lenard // 1987 4th International Steel Rolling Conference, Deauville, France.
89. J. G. Lenard, A. Said, A. R. Ragab, M. Abo Elkhier. "The Temperature, roll force and roll torque during hot bar rolling." / J. G. Lenard, A. Said, A. R. Ragab, M. Abo Elkhier // 1997 Journal of Material Processing Technology: 147-153.
90. Alexander. J.M. On the theory of rolling. / J. M. Alexander // Proceedings Rolling Society, 535-555, London 1972.
91. Turner. M. J. "Stiffness and Deflection Analysis of Complex Structures." / M. J. Turner, R. W. Clough, H. C. Martin and L. J. Topp. // 1956 Journal of Aeronautical Science23: 805-823.
92. Zienkiewicz O. C. The Finite Element Method / O. C. Zienkiewicz // 1977 New York, McGraw-Hill.
93. Gun, G. A. Mathematical modeling of metal forming processes / G. A. Gunn // M.: Metallurgy. 1983 352 p.
94. Hartley, P. Friction in time element analyzes of metalforming processes / P. Hartley, C.E.N. Strugess, G. W. Rove / Int. J. Mech Sci Vol. 21 pp 301 311, 1979.
95. T. Sheapad D.S. Wright Structural and temperature variations during rolling of aluminum slabs / T. Sheapad D.S. // Metals Technology, 1980 No. 7.
96. Smirnov B.C. Theory of metal forming. / B.C. Smirnov // publishing house "Metallurgy" 1967. 520 p.
97. Kudryavtsev, I.P. Textures in metals and alloys / I.P. Kudryavtsev // M.: Metallurgiya, 1965. 292 p.
98. Kovalev, S.I. Stresses and strains during flat rolling / S.I. Kovalev, N.I. Koryagin, I.V. Shirko // M.: Metallurgiya, 1982. 256 p.
99. J Hirschi, K-KraHausen, R. Kopp; in "Aluminum Alloys", proceedings ICAA4 Allanta/GA USA (1994) edite by T.N. Sanders, E.A. Starke, vol 1, p. 476.
100. Mori, K. "General purpose fem simulator for 3-d rolling." / Mori K. // 1990 Advanced Technology of Plasticity 4: pp 1773-1778.
101. Park J. J. "Application of three dimensional finite element analysis to shape rolling processes."/ J. J. Park and S. I. Oh // 1990 Transaction ASME Journal of Engineering Ind 112: 36-46.
102. Yanagimoto, J. "Advanced computer aided simulation technique for three dimensional rolling processes." / J. Yanagimoto and M. Kiuchi // 1990 Advanced Technol. Plas 2: 639-644.
103. Kim, N. S. "Three-dimensional analysis and computer simulation of shape rolling by the finite and slab element method." / N. S. Kim, S. Kobayashi, T. Altan // 1991 International Journal of Machine and Tool Manufacture (31): 553563.
104. Shin, H. W. "A Study on the Rolling of I-Section Beams." / H. W. Shin, D. W. Kim, N. S. Kim // 1994 International Journal of Machine and Tool Manufacture 34(147-160).
105. Park, J. J. "Three-dimensional finite element analysis of block compression." / J. J. Park, S. Kobayashi // International Journal of Mechanical Sciences 26: pp 165-176.
106. Hacquin, A. . "A steady state thermo-elastoviscoplastic finite element model of rolling with coupled thermo-elastic roll deformation." / A. Hacquin, P. Montmitonnet, J-P. Guillerault // 1996 Journal of Material Processing Technology 60: 109-116
107. Nemes, J. A. "Influence of strain distribution on microstructure evolution during rod-rolling." / J. A. Nemes, B. Chin and S. Yue // 1999 International Journal of Mechanical Sciences 41: pp 1111-1131.
108. Hwang, S. M. "Analytic model for the prediction of mean effective strain in rod rolling process." / S. M. Hwang, H. J. Kim, Y. Lee // 2001 Journal of Material Processing Technology, 114: 129-138.
109. Serajzadeh, S. "An investigation on strain homogeneity in hot strip rolling process." / S. Serajzadeh, K. A. Taheri, M. Nejati, J. Izadi and M. Fattahi. // 2002 Journal of Material Processing Technology 128: 88-99.
110. Li G. J. "Rigid-plastic finite element analysis of plain strain rolling." / G. J. Li and S. Kobayashi // 1982 Journal of Engineering for Industry 104: 55.
111. Mori, K. "Simulation of plane-strain rolling by the rigid-plastic finite element method." / K. Mori, K. Osakada, T. Oda // 1982 International Journal of Mechanical Sciences24: 519.
112. Liu, C. "Simulation of the cold rolling of strip using a elastic-plastic finite element technique." / C. Liu, P. Hartley, C. E. N. Sturgess and G. W. Rowe // 1985 International Journal of Mechanical Sciences 27: 829.
113. N. Kim. "Three-dimensional simulation of gap controlled plate rolling by the finite element method." / N. Kim, S. Kobayashi // 1990 International Journal of Machine and Tool Manufacturing 30: 269.
114. Hwang, S. M. "Analysis of hot-strip rolling by a penalty rigid-viscoplastic finite element method." / S. M. Hwang, M. S. Joun // 1992 International Journal of Mechanical Sciences 34: 971.
115. Khimushin F.F. Heat-resistant steels and alloys. / F.F. Khimushin // M.: Metallurgiya, 1969. 752 p.
116. Korneev, N.I. Plastic deformation of high-alloy alloys / N.I. Korneev, I.G. Skugarev //. Oborongiz, 1955 245 s
117. Korneev, N.I. Fundamentals of the physicochemical theory of metal pressure treatment. / N.I. Korneev, I.G. Skugarev // M.: Mashingiz, 1960. 316 p.
118. Lakhtin, Yu.M. Metal science / Lakhtin, Yu.M. // M.: Mashinostroenie, 1980. 493 p.
119. Aryshensky, V.Yu. Fundamentals of calculations of limiting shape change in the processes of sheet bending / Aryshensky V.Yu., Aryshensky Yu.M., Uvarov V.V. // Textbook. Kuibyshev: KuAI, 1990. 44 p.
120 Morris, J.P. A furher analysis of the earning behavior of AA 3104 aluminum alloy. Aluminum 66 / J.P. Morris, Z. Li. Lexington, L. Chen, S. K. Das // Jargang 1990 11 (pp. 1069-1073)
121. Bahman, Mirzakhani. Investigation of Dynamic and Static Recrystallization Behavior During Thermomechanical Processing in API-X70 Microalloyed Steel / Bahman Mirzakhani, Hossein Arabi, Mohammad Taghi Salehi,
122. Shahin Khoddam, Seyed Hossein Seyedein and Mohammad Reza Aboutalebi // Journal of Materials Engineering and Performance
123. Siciliano F. Jr Mathematical modeling of the hot strip rolling of microalloyed Nb, multiply-alloyed Cr-Mo, and plain C-Mn steels / Siciliano F. Jr ; J. J. Jonas// 2000, vol. 31, no. 2, pp. 511-530 (63 ref.)
124. Dutta B. Modeling the kinetics of strain induced precipitation in Nb microalloyed steels / V. Dutta // Acta Materialia, Volume 49, Issue 5, Pages 785-794
125. Barnet, M. R., Kelly, G. L., Hodgson, P. D., Predicting the critical strain for dynamic recrystallization using the kinetics of static recrystallization. / M. R. Barnet, Kelly,. P. D. Hodgson, // Scripta Materialia, 43, 4, 365-369.
126. Aryshensky V.Yu. Development of a mechanism for the formation of a given anisotropy of properties in the process of rolling tapes for deep drawing with thinning. Doc. diss. Samara, 202. 312 p.
127. GOST 5639-82 Steels and alloys. Methods for identifying and determining the size of the grain.
Please note that the scientific texts presented above are posted for review and obtained through recognition of the original texts of dissertations (OCR). In this connection, they may contain errors related to the imperfection of recognition algorithms. There are no such errors in the PDF files of dissertations and abstracts that we deliver.
GOST 8732-78 applies to continuous pipe products that do not have a welded joint, obtained by hot deformation on pipe mills - seamless hot-formed steel pipes. They significantly outperform their welded counterparts in terms of strength and resistance to deformation. This allows them to be widely used in machine-building, chemical and oil-producing industries and other critical areas.
According to the state standard, seamless hot-rolled pipe is manufactured in different overall dimensions:
- random length (in the range of 4-12.5 m);
- measured length in established sizes;
- multiple measured length;
- length, multiple measured;
- approximate length (within unmeasured).
The range according to GOST 8732-78 regulates the outer diameters of hot-rolled pipe and its wall thickness. Technical requirements for products are established by GOST 8731-74.
According to the ratio of the size of the outer diameter to the wall thickness (Dн / s), seamless steel pipes manufactured by hot-rolled methods are classified as follows:
- especially thin-walled pipes Dn/s > 40 and pipes with a diameter of 20 mm and wall thickness ≤ 0.5 mm;
- thin-walled with Dn / s from 12.5 to 40 and pipes D ≤ 20mm with a wall of 1.5 mm;
- thick-walled with Dн/s from 6 to 12.5;
- extra thick-walled with Dн/s< 6;
According to quality indicators, seamless-rolled hot-rolled pipes are divided into
five groups:
A - with the rationing of the mechanical properties of products;
B - with the regulation of the chemical composition of the steel used;
B - control of the mechanical properties of the steel used and its chemical composition;
D - with the regulation of the chemical composition of the steel used and the mechanical properties of products;
D - without rationing of mechanical properties and chemical composition, but with hydraulic tests.
and six grades:
- Standard and gas pipes made of carbon raw materials are used in structures and communications for which there are no special requirements. Class 1 pipes are used in the construction of building structures, fences, cable supports, irrigation structures.
- Carbon steel pipes for main water, gas, fuel and oil pipelines of various pressures.
- Pipes for systems operating under pressure and at high temperatures in cracking systems, steam boilers and other critical equipment.
- Drilling, casing and auxiliary pipes used in geological exploration and operation of oil and gas wells.
- Structural tubes for car building, car building, manufacturing of massive steel structures: supports, cranes, masts, oil rigs.
- Pipes used in the engineering industry for the manufacture of machine parts and mechanisms: cylinders, piston groups, bearing rings, containers operating under pressure. GOST 8732-78 "Seamless hot-formed steel pipes" (the price is indicated in the catalog ) distinguishes between small outer diameter pipes (up to 114 mm), medium (114-480 mm) and large (480-2500 mm and more).
Seamless hot-formed steel pipes GOST 8732-78: description of manufacturing technology
The process of manufacturing pipes by hot rolling consists of three technological stages:
- Firmware. Production of a thick-walled sleeve of a solid round steel billet.
- Rolling out. Deformation of the sleeve on the mandrel in rolling mills. To reduce wall thickness and diameter.
- Hot finish. To improve the surface quality and obtain more accurate pipe dimensions, the workpiece is subjected to hot finishing, running, calibration or reduction.
All technological processes for the manufacture of rolled pipes begin from the table of blanks. Here, blanks of the required length are obtained from round solid rods, breaking them on hydraulic presses along pre-made cuts or cutting them on press scissors without preheating.
After assembling a package of blanks, they are sent to a loading machine with a double-row load. The heating temperature is 1150-1270℃, depending on the steel grade. After heating, the workpiece is sent along roller tables and racks to a centerer, on which a recess is made in the end along its axis. After that, the workpiece is fed into the trough of the piercing mill.
Piercing mills are disc, barrel-shaped and mushroom-shaped. For piercing the workpiece, stands with barrel-shaped rolls rotating in one direction are most often used. The axes of the rolls are in vertical planes parallel to the axis of symmetry of the mill. Moreover, the roll axis makes an angle ß (feed angle) with the piercing axis from 8 to 15 degrees, depending on the size of the sleeve.
The hole in the sleeve is formed by a mandrel, which is fixed on a long fixed rod. Their axes coincide with the firmware axis. The heated billet moves towards the rolls towards the mandrel installed in the zone of the maximum diameters of the rolls - pinching. When in contact with the rolls, the workpiece begins to move in the opposite direction, and due to the feed angle it receives translational motion, which provides a helical trajectory for each point of the deformed metal. This results in a thick-walled sleeve.
The outer diameter of the sleeve is approximately equal to the diameter of the workpiece, but due to the formation of the hole, its length increases by 2.5-4 times compared to the original length of the workpiece.
The sleeve obtained on the piercing mill is subjected to rolling into a pipe of the required diameter and wall thickness in various ways. The method of rolling the sleeve into a pipe characterizes the type of pipe rolling plant. Under the conditions of PNTZ, this is rolling on automatic, continuous and three-roll rolling mills.
Methods for hot rolling of pipes
Rolling on an automatic mill
Units with an automatic mill have received the most widespread use. A wide range of rolled pipes with a diameter of 57 to 426 mm and a wall thickness of 4 to 40 mm, as well as easy conversion to pipes of other sizes provide great maneuverability on such a unit. These advantages are combined with a fairly high performance.
Structurally, the automatic mill is a two-roll non-reversible stand, on the rolls of which there are streams forming a round pass. Before the task of the sleeve in the rolls, a stationary short round mandrel on a long rod is installed in the gauge, so that the gap between the mandrel and the gauge determines the diameter of the pipe and its wall thickness. The metal is deformed between the rolls and the mandrel. In this case, along with the thinning of the wall, there is a decrease in the outer diameter of the pipe.
Since rolling in one pass does not provide uniform deformation of the wall along its perimeter, it is necessary to give two, and sometimes three passes, each time with turning, i.e. with the pipe turning by 90 degrees around its axis before turning it into rolls.
After each pass, the rolled sleeve is transferred to the front side of the stand by means of a pair of reverse feed friction rollers mounted on the exit side of the mill. They rotate in the direction opposite to the rotation of the rolls. The mandrel after each rolling is removed manually or with the help of mechanisms and reinstalled before the next task of the sleeve.
The sleeve from the piercing mill enters the chute and is pushed into the rolls by the pusher. After the first pass, the billet returns, turns around the axis by 90 degrees and is again fed into the rolls by the pusher. After each pass, the mandrel is changed.
Production of pipes on a three-roll rolling mill
On three-roll rolling mills, pipes with a diameter of 34 to 200 mm and a wall thickness of 8 to 40 mm can be rolled. The main advantage of this rolling method is the possibility of obtaining thick-walled pipes with a minimum thickness variation compared to the methods of rolling pipes in round calibers.
The deformation of the sleeve into a pipe is carried out using three rolls and a movable long mandrel. The rolls are equidistant from each other and from the rolling axis. The axes of the rolls are not parallel to each other and between the rolling axis. The angle of inclination of the roll axis to the rolling axis in the horizontal plane is called the rolling angle φ, which is usually equal to 7 degrees. And the angle of inclination of the vertical plane is called the feed angle ß and varies in the range of 4-10 degrees, depending on the dimensions of the rolled pipes. The rolls rotate in one direction and, due to the misalignment of their axes relative to the rolling axes, create conditions for the helical movement of the sleeve together with the mandrel.
Once on the gripping cone of the rolls, the sleeve billet with the mandrel inside is compressed along the diameter and along the wall. The deformation along the wall is carried out mainly by the crests of the rolls. On the rolling and sizing cones, the wall thickness is leveled, ovalization is reduced, and there is a slight increase in the inner diameter of the billet. This creates a small gap between the walls of the future pipe and the mandrel, which makes it easier to remove the latter from the pipe after rolling.
As a calibration equipment for thick-walled pipes, a three-roll mill is used, similar in design to a rolling mill, but less powerful, since the deformation in diameter is small here, and the wall thickness remains unchanged.
For pipes of smaller diameters and with smaller wall thicknesses, a continuous sizing mill consisting of five stands is used.
The productivity of the unit with a three-roll rolling mill is up to 180 thousand tons of pipes per year. The advantages of these mills include the possibility of obtaining high-precision pipes, fast changeover from size to size, good quality of the inner surface of the products.
Production of seamless pipes on a continuous mill
The process of rolling the sleeve in a continuous mill takes place in a number of successively arranged two-roll stands. The rolling is carried out on a long movable cylindrical mandrel in stands with rolls having round calibers.
As in the automatic mill, the cross section of the pipe is determined by the annular gap between the roll grooves and the mandrel. With the difference that the long mandrel moves along with the rolled pipe.
As it passes through the stands, the number of which can reach nine, the sleeve is reduced: it decreases in outer diameter and is compressed along the wall. Since the deformation in round passes occurs unevenly, the pipe after the stand has an oval shape, it must be set by the larger axis of the oval along the height of the pass, i.e. rotated 90 degrees around the axis. To do this, change the direction of deformation of the rolls. To do this, each subsequent stand is rotated relative to the previous one at a right angle, and the stands themselves are located at an angle of 45 degrees to the horizon. This allows you to increase the reduction in the stands and increase the compression of the pipes.
The continuous mill is designed for a high elongation ratio of up to 6, so the length of the pipe can reach 150 meters. On a continuous mill, pipes with a diameter of 28 to 108 mm with a wall thickness of 3 to 8 mm and a length of more than 30 meters are produced. High rolling speed (up to 5.5 m/s) ensures high productivity (up to 600 thousand tons of pipes per year).
The final technological operation for all pipe rolling methods is the operation of product cooling on cooling tables. To eliminate longitudinal curvature, the cooled pipes are straightened on straightening mills. Special calibrated rolls of the mill carry out the helical movement of the pipe, while eliminating the existing axial curvature. Pipe ends are trimmed on lathes. Chamfers are removed if necessary.
At the end, the finished products are subject to quality control. Suitable pipes after inspection are packaged on a knitting machine, after which they are sent to the finished product warehouse.
Seamless hot-formed pipes GOST 8732-78: applications
Hot-rolled seamless steel pipes are widely used in the construction of pipelines of all diameters, used for the production of metal parts, machine and mechanism elements, columns, trusses and beams, foundation piles, lighting poles, housing and communal services and road construction.
From the technical characteristics of a hot-rolled pipe according to GOST, the scope of its application follows. These are highly critical pipelines that require extreme strength, which practically excludes the possibility of leaks:
- In energy. Seamless steel pipes hot-formed in accordance with GOST 8732-78 are used to create working medium circulation systems in boilers and to direct superheated steam to turbines.
- in the chemical industry. In addition to transporting liquids and gases under high pressure, the use of seamless steel pipes is sometimes due to the desire to avoid the slightest leaks.
- In the aviation industry. In this industry, thin-walled seamless hot-formed pipes according to GOST 8732-78 are most in demand - they combine maximum strength, small wall thickness with low weight.
- In hydraulics. Pistons and cylinders must withstand extremely high pressures, which only seamless hot-formed metal products with large wall thicknesses and extremely high strength can withstand.
- In the field of oil and gas processing and transportation. Although high-quality welded pipes are used in most main pipelines, in sections with high pressures of hundreds of atmospheres, thick-walled seamless pipes produced by hot deformation are indispensable.
In catalog warehouse complex "ChTPZ" presents a wide range of steel hot-formed seamless pipes in accordance with GOST 8732-78 for the needs of the oil and gas industry, chemical industry, construction, utilities and agriculture. You can place an order online or by phone . Compliance with the requirements of the state standard guarantees high technical and operational characteristics and a long service life of the rolled pipe sold. All products are supplied with quality certificates.
