Round Billet Research Articles

Drawing of Square Blanks in a Cylindrical Die with Controlled Movement of the Edges

Plastic forming, in many cases, includes the drawing of hollow cylindrical products as the main operation. For the manufacture of such products, round blanks are used as semi-finished products. However, during the blank production from strips or tapes, their geometry causes a very significant metal loss. A very effective way to reduce metal loss is to replace round billets with square ones. The use of square blanks gives an additional increase in the height of the products. In this regard, the article investigates the drawing of a square blank into a cylindrical die. The research was carried out on the basis of the analysis of experimental work and computer modeling. According to the results of the research the rational ratios of the geometric dimensions of the tool and workpieces are found.

Effect of Internal Electromagnetic Stirrings DC Casting on Grain Refinement and Segregation of Large-Sized Billet of 2219 Alloy

An advanced method called internal electromagnetic stirring (I-EMS) was investigated to resolve the engineering problems like coarse-grain, inhomogeneous structure and macrosegregation. The electromagnetic stirrer functioned with internal-cooling was inserted in the melt during DC casting. In this study, a round billet of 2219 alloy DC cast with a diameter of 880mm under I-EMS process condition was produced, and its structure and composition distribution were comparatively characterized. The results show that the mean grain size decreased from the range of 872, 1023, 332 μm to the range of 317, 438, 271 μm at different billet positions with I-EMS. I-EMS consequently produce superior grain refinement and homogeneity. The effect of I-EMS on the grain-refinement and macrosegregation was also discussed.

Analytical and Numerical Analysis of Extrusion Force, Stress and Strain Development During Extrusion Al6063-SiC Composite

Nowadays composite material are highly interesting in different areas like, aerospace, thermal management, automotive application, and electronic products etc. Aluminium based metal matrix with silicon carbide as particle reinforcements called discontinuous reinforced metal matrix composite materials. It has excellent mechanical properties like high yield strength, wear resistance, corrosion resistance and vibration resistance. During the development of discontinuous reinforcement metal matrix composites compression process like, extrusion is an advisable secondary process for homogenous distribution of the reinforcement’s materials through the metal matrix. This research was investigated the metal flow behavior of extrusion load, stress and strain distribution of Al6063/Sic based discontinuous reinforcement metal matrix composite. The billets extruded from round billet to square shape and are used for different applications. Third order polynomial and cosine die profiles were used as extrusion dies for this research by taking 30%, 60% and 90% area reductions. Depends on these three different area reductions upper bound and DEFORM 3D finite element analysis method were used to analyze analytically and numerically respectively. Due to these different area reductions, the extrusion load was minimum in cosine die profiles both analytical and numerical results. In 30% of area reduction cosine die profile has optimum load (878.59N) and it used to extrude Al6063/20%SiC composite billet materials from 20mm input diameter to 14.8x14.8mm output square sides. Therefore, 30% area reduction cosine die profile has minimum extrusion load as compare other area reduction of cosine die and 3rd order polynomial dies. It is used as extrusion die for Al6063/SiC composite materials to optimum extrusion loads in different % of area reduction of square shape extruded.

Investigation structure and properties of wire from the alloy of AL-REM system obtained with the application of casting in the electromagnetic mold, combined rolling-extruding, and drawing

The paper presents the results of studies of the structure and properties of a wire with a diameter of 0.5 mm from an alloy of the Al-REM system with a rare-earth metal content of 7–9%. Wire obtained as a result of the implementation of the technology of its manufacture using the methods of casting into an electromagnetic mold (EMM), continuous extruding, and drawing. The rheological properties of the metal of continuously cast round billets from the experimental alloy obtained using an electromagnetic mold are determined. The modeling and analytical assessment of the possibility of carrying out the process of combined rolling-extruding (CRE) of such billets in a closed box-type roll groove of a continuous extruding unit are carried out. The features of metal shaping have been studied. The temperature-speed and technological parameters were found at which the CRE process can be carried out in a stable mode of operation. Data have been obtained for the forces acting on the die and rolls during rolling-extruding. The results of experimental studies of the process of obtaining longish deformed semi-finished products from an experimental alloy on the laboratory unit CRE-200 and the pilot plant unit CRE-400 are presented. The structure of the metal has been studied; data on the ultimate tensile strength, yield strength, relative elongation, and electrical resistance of hot-extruded rods and wires in cold-worked and annealed states have been obtained. It was found that the proposed processing modes make it possible to obtain by the method of combined rolling-extruding rods with a diameter of 9 mm in industrial conditions from longish billets with a diameter of 18 mm, cast by means of EMM. Wire in a cold-deformed and annealed state with a diameter of 0.5 obtained by drawing from the rods with a diameter of 9 mm from an experimental alloy of the Al-REM system containing 7–9% rare-earth metals with the required physical and mechanical properties.

Evaluation of efficiency of methods for drawing round wire with large diameters

Drawing in monolithic draw dies is the primary and often nonalternative pressure metal treatment (PMT) method used in the wire manufacture for various purposes both in our country and abroad. Its effectiveness largely depends on the wire diameter and properties. Thus, when drawing wire of large diameters (>8.0 mm) from high-carbon steels (high-tensile reinforcing wire, spring wire, etc.), the stability of the process and the probability of metal fraction decreases. The use of classic roller draw dies increases the strain uniformity along the wire cross-section, reduces the force and multiplicity of drawing. However, the «circle-shaped section-circle» roller gauge system used in this process leads to a more complicated process, and most importantly, to a significant increase in production costs. In this paper, a comparative analysis of the drawing efficiency of a round billet with a diameter of 16.00 mm from steel grade 80 into a wire with a diameter of 14.25 mm (strain degree 21%) in one step in the classic monolithic draw die and roller draw dies: three-roller draw die with a spatially closed round gauge and three-roller draw die of radial shear strain. The latter is comparable to the well-known radial-shear rolling. The difference is that the energy is introduced into the deformation zone by applying a front pulling force, and the idler rollers rotate around the wire with a special drive. The authors used finite element modeling in the Deform-3d software package. The deformed state in processes with linear tensile strain was estimated by the distribution of the accumulated strain degree in the billet cross-section, and in processes with torsion – by the change in the curvature of the line applied to the side surface of the billet. The power parameters were determined in Deform-3d in the coordinates: drawing force – time of billet movement. The stress state was determined by the hydrostatic stress on the wire axis and the Cockcroft-Latham fracture criterion. It is established that the wire strain in a monolithic draw die is characterized by a significant strain inhomogeneity across the cross-section, monotonous flow, high energy consumption, and the wire collapsibility, especially of the mid-layers. The use of draw dies with a spatially closed round gauge reduces the drawing force by about 40%, reduces the degree of strain inhomogeneity along the cross-section, and increases the degree of accumulated strain. The radial-shear strain drawing significantly increases the degree of accumulated strain and provides grain grinding, especially in the surface layers of the wire.

Improvement of the tube mold to ensure uniform primary cooling of the ingot

For centering the cooling jackets of CCM tube molds relative to the tube, bolts twisted into the jacket are used. The adjustment is made manually, as a result the annular gap between the sleeve and the jacket can have a significant deviation from the specified values. The gap function is to cool the structure by passing water. Taking into account that almost all the modern CCMs for casting long, bloom and round billets are equipped with tube molds, creating a mold design in which the gap between the tube and the cooling jacket is formed with a high degree of accuracy, ensuring uniform heat removal from the walls of the tube is an urgent task. This is necessary to ensure a uniform thickness of the shell of the solidifying billet. The conditions were considered for the formation of a uniform shell of a solidifying ingot in a mold and the production of a billet that meets the requirements for its surface and geometric dimensions, the absence of internal and external cracks of thermal origin. It was shown that the violation of the alignment of the cooling jacket and the tube surfaces results in violation of the uniformity of the cooling water flow. The difference in the volume of water flowing in various parts of the gap between the tube and the jacket can reach 40%. When casting billets with diameters of 600 and 550 mm, the difference in heat flows due to misalignment in existing molds can be 30–40% and 25–35% respectively, and with a cross section of 300×400 mm – 13–23%. In order to eliminate these shortcomings, a new design of the tube mold was developed in VNIIMETMASH (Moscow), in which the gap between the sleeve and the cooling jacket is formed with high accuracy, ensuring uniform heat removal from the walls of the tube and obtaining a uniform thickness of the shell of the solidifying ingot. This will ensure that the casted billet meets the requirements for its quality parameters and geometric dimensions. The diagram of the designed mold for the bloom CCM, which produces billets with a cross section of 340×380 mm is presented.

Deformation Texture Evolution in Flat Profile AlMgSi Extrusions: Experiments, FEM, and Crystal Plasticity Modeling

In the present work, the deformation textures during flat profile extrusion from round billets of an AA6063 and an AA6082 aluminium alloy have been numerically modeled by coupling FEM flow simulations and crystal plasticity simulations and compared to experimentally measured textures obtained by electron back-scatter diffraction (EBSD). The AA6063 alloy was extruded at a relatively low temperature (350°C), while the AA6082 alloy, containing dispersoids that prevent recrystallization, was extruded at a higher temperature (500°C). Both alloys were water quenched at the exit of the die, to maintain the deformation texture after extrusion. In the center of the profiles, both alloys exhibit a conventional β-fiber texture and the Cube component, which was significantly stronger at the highest extrusion temperature. The classical full-constraint (FC)-Taylor and the Alamel grain cluster model were employed for the texture predictions. Both models were implemented using the regularized single crystal yield surface. This approach enables activation of any number and type of slip systems, as well as accounting for strain rate sensitivity, which are important at 350°C and 500°C. The strength of the nonoctahedral slips and the strain-rate sensitivity were varied by a global optimization algorithm. At 350°C, a good fit could be obtained both with the FC Taylor and the Alamel model, although the Alamel model clearly performs the best. However, even with rate sensitivity and nonoctahedral slip systems invoked, none of the models are capable of predicting the strong Cube component observed experimentally at 500°C.

Rational Distribution of Surface Cooling Intensity for a Round Continuously-Cast Billet in Secondary Cooling Zone

A method for determining the rational distribution of cooling intensity of a round billet in a SCZ within which the amount of heat removed from the surface of the calculated section of the billet at each instant of time is equal to the sum of the amount of heat released at the solidification front and the amount of heat corresponding to already solidified metal mass cooling at a specified rate, is proposed. The adequacy of the method is verified by prescribing the distribution of the cooling intensity obtained as boundary conditions in a mathematical model of the temperature field of a continuously cast billet. During treatment of the simulated results values of the solidification coefficient are established that within the limits of the permissible error are consistent with the values used as starting data within the framework of the method proposed.

Element-Free Galerkin Method Modeling of Thermo-Elastic-Plastic Behavior for Continuous Casting Round Billet

When solving the coupled thermal-mechanical problem of the metal solidification, the mesh-based numerical methods suffer from the inconsistency of mesh lines and curved boundaries. Furthermore, the mesh should be continually reconstructed to comply with the interface when dealing with the moving boundary such as phase transition, which brings great difficulties to the numerical calculation. Based on the plane stress assumption, the present work establishes a two-dimensional thermo-elastic-plastic calculation model for continuous casting round billets using the Element-Free Galerkin method, and the correction scheme of elastoplastic transition region has been explored. The results show that the correction scheme has a slight effect on magnitude of the equivalent stress and no impact on the subsequent plastic deformation zone. The elastoplastic transition region of shell surface appears in the range of 100 to 200 mm below the meniscus, and the averaged plastic stress is about 2.27 times of the elastic stress at the mold outlet. Near the interface region of liquid–solid phase exhibits an elastic deformation behavior, while far from the interface region appears plastic deformation in which the elastic stress remains invariable. The Element-Free Galerkin method is discretized by a series of arbitrary nodes, which exhibits high accuracy and great flexibility in dealing with moving interface problems. It provides a powerful approach to calculate and analyze the heat transfer/mechanical behavior with complex geometric boundaries such as round billet, chamfered billet, and beam blank.

ВИГОТОВЛЕННЯ ОСЕЙ ЧОРНОВИХ ПОПЕРЕДНЬО ОБРОБЛЕНИХ МЕТОДОМ ОБТОЧУВАННЯ КРУГЛОЇ ЗАГОТОВКИ

The article deals with the definition of the term “rough axle” (profile billet). Among other things, data on the manufacturing process of axle billets, as well as manufacturing methods for rough axles in Ukraine are presented. Rough axles in our country are manufactured using three different methods of hot-forming process: free forging, screw rolling and radial-rotation profile forming. New method of manufacturing a pre-machined rough axle is described. References to the paper, i.e., determination of comparative characteristics of internal defects of different types of rough axles produced by several domestic manufacturers using various methods and technological processes are made. These characteristics were determined by the Testing Center for railcar-building products of DP "UkrNDIV" during different types of testing rough axles manufactured in the period from 2002 to 2017. The testing is described and the parameters of the test objects which were determined, namely, geometrical dimensions, surface integrity, marking, testing of sound permeability and internal defects of the axles, chemical composition and mechanical characteristics of the axle structure, macrostructure cleanliness, nonmetallic inclusions in the steel, micrographic cleanliness are indicated. Also, the testing results of pre-machined rough axles, manufactured by the method of turning the round billet, carried out by the Testing Center of DP "UkrNDIV" in the period from 2018 to 2021 are presented. Findings based on the tests results are set forth, that is, the tested parameters of test objects meet the requirements of regulatory documentation, steel-melting and manufacturing technological processes for rough axles manufactured by PJSC "INTERPIPE NTRP" comply with DSTU HOST 31334:2009, DSTU HOST 4728:2014 and TU U 30.2-23365425-701:2018. The list of literature sources including state standards and technical specification used while writing the paper and the article itself are given. Key words: rough axle, continuously steel-casting method, round billet.

Influence mechanism of large inclusion on wheel fatigue crack

In this paper, the formation mechanism of wheel rim crack and control technique was investigated. Feature of wheel rim crack and aggregated attachments on the inner wall of nozzle were examined through scanning electron microscope and energy dispersive spectrometer. Metal rheological test of round billet rolling was conducted to investigate the corresponding location of large inclusions in the round billet and in the wheel. It was found that the rim crack of wheels during service is caused by large inclusions that originated from the aggregated inclusions on the inner wall of the nozzle. According to Murakami’s modelling, the critical size of the inclusions that initiate cracks relates to the depth from the tread. The critical sizes of the inclusions for cracks initiation at 10 mm, 14 mm, 16 mm and 20 mm below the tread are about 0.1 mm, 0.2 mm, 0.5 mm and 1.5 mm, respectively. Process optimization was made with combination of a series methods. Dispersed annular venting stopper was adopted to block the aggregation and attachment of inclusions on the inner wall of nozzle. Current and frequency of electromagnetic stirring in mold were increased to restrain the impact depth of molten steel flow and inclusions. Cooling intensity of the secondary cooling was decreased to reduce the probability of inclusions captured at the solidification front. After optimization, the number of large inclusions was greatly reduced by more than 80%, and the number of inclusions larger than 1 mm is greatly reduced from 35% to 8%. The risk of wheel rim cracks occurrence could be reduced greatly.

ДО ПИТАННЯ ПРО ВИЗНАЧЕННЯ ГРАНИЧНИХ УМОВ ПРОЦЕСУ ПРОКАТКИ-ВОЛОЧІННЯ У ЗДВОЄНИХ РОЛИКОВИХ ВОЛОКАХ

There is a great demand in the world for steel strip profiles, which are widely used in mechanical engineering, instrument making and other sectors of the national economy. In Ukraine, the production of strip profiles is extremely limited. The production volumes of such products, if a wide range of sizes and brands are required, are relatively small. The creation of large specialized enterprises for the production of strip profiles in these conditions is economically unprofitable, the orientation towards the import of these profiles makes the economic and technological security of Ukraine dependent on foreign suppliers. For the production of high-precision profiles, various combinations of basic shaping and auxiliary processes are used, depending not only on the characteristics of the profile itself and the technical requirements of the supply, but also on the size of the ordered batch and the capabilities of the available equipment. This explains the high complexity of technological design. The aim of the work is to determine the boundary conditions of deformation in double roller dies, which ensure a stable flow of the drawing process according to the criterion of the safety factor of the deformed metal. It was found that when calculating the transitions of drawing strip profiles during deformation of the initial round billet with a diameter of 3.67 mm from steel St.70 with a width to thickness ratio of more than two, the maximum value of the relative reduction per transition should not exceed 40-50 % during deformation without counter tension, and 40 % – with tension. Analytical studies have shown that in the range of working reductions per transition (5-40 %), the safety factor that guarantees the process of metal deformation without breakage and does not allow local constrictions and distortion of the profile geometry is not exhausted. It was found that in the range of working reductions per transition (5-40 %), the deformation process of the initial round billet in a roller die with smooth rollers proceeds without exceeding the permissible values of the drawing forces. It has been determined that with an increase in the relative reduction in the first roller die, the range of working reductions in the second roller die, which affects the stability of the metal drawing process, decreases.

Rheological behavior of a Cu-Cr alloy subjected to severe plastic deformation

The choice of rate conditions of deformation is one of the key factors that determine the mode of thermomechanical processing of metallic materials. The aim of this work is to study the rheological behavior as well as the structural response of the Cu-0.6Cr alloy under conditions of large deformations. For this, physical modeling of upsetting of specimens on a Gleeble 3500 installation at deformation rates of 3, 30, and 300 mm/s, structural characterization of the obtained specimens and computer simulation of the equal-channel angular pressing (ECAP) process in the Deform 3D software package were carried out. It was found that with an increase in the rate of deformation, the value of deformation heating increased. If at the rate of ECAP 30 mm/s and at the initial temperature of 20°C, the temperature of the main volume of a round billet with a diameter of 20 mm reached 80-90°C, at 300 mm/s increased up to 150°C. It is shown that with an increase in the deformation rate up to 300 mm/s the necessary pressing forces increase by 1.5 times, and, accordingly, the pressures during pressing and the load on the tool increase.

Simulaling the Faceted Tube Drawing

The paper studies cold-sinking of four-, six-, and eight-faceted steel tubes from round billets in a single pass. The built mathematical model of the process objectively describes the drawing and allows forecasting the geometric and deformation parameters of the pipes processed, as well as the power parameters of the process. The model accuracy has been confirmed by a series of parallel calculations and a comparative calculation in two software packages. The results have shown satisfactory convergence. The theoretical experiment results have been verified by performing a full-scale one. The results have also been consistent. The research results are of practical use to the process equipment manufacturers and consumers.

A Useful Manufacturing Guide for Rotary Piercing Seamless Pipe by ALE Method

The development of numerical simulations is potentially useful in predicting the most suitable manufacturing processes and ultimately improving product quality. Seamless pipes are manufactured by a rotary piercing process in which round billets (workpiece) are fed between two rolls and pierced by a stationary plug. During this process, the material undergoes severe deformation which renders it impractical to be modelled and analysed with conventional finite element methods. In this paper, three-dimensional numerical simulations of the piercing process are performed with an arbitrary Lagrangian–Eulerian (ALE) formulation in LS-DYNA software. Details about the material model as well as the elements’ formulations are elaborated here, and mesh sensitivity analysis was performed. The results of the numerical simulations are in good agreement with experimental data found in the literature and the validity of the analysis method is confirmed. The effects of varying workpiece velocity, process temperature, and wall thickness on the maximum stress levels of the product material/pipes are investigated by performing simulations of sixty scenarios. Three-dimensional surface plots are generated which can be utilized to predict the maximum stress value at any given combination of the three parameters.

Feasibility Analysis of Cross Wedge Rolling (CWR) of Hexahedral Billet

In order to expand the product range of cross wedge rolling (CWR) and realize the CWR of hexahedral billet, the hexahedral CWR is studied. In this paper, a three-dimensional finite element model (FEM) of hexahedral cross wedge rolling is established by using DEFORM software. In this paper, a three-dimensional FEM of hexahedral CWR is established by using DEFORM finite element software. The change and distribution of equivalent stress and strain in the rolling process of hexahedral billets are analyzed. By tracking the strain in the rolling core of hexahedral billet, the change law of strain in each stage of forming process is obtained. The equivalent strain during the manufacturing process, the obtained CWR of hexahedral billet and round billet are basically the same. The feasibility of CWR of hexahedral billet is further verified by experiments. The research results provide theoretical guidance for realizing CWR of hexahedral billet.

Development of steel continuous casting at the Nizhny Tagil steel-works

Steel continuous casting is one of fundamentals of modern steel industry. Specialists of Nizhny Tagil steel-works (NTMK) made an important contribution to the process perfection. The one-strand slab CCM of curvilinear type with radial mold and slab straightening by multipoint curve, designed and manufactured at Uralmashzavod, became a prototype for many machines, which were later manufactured at domestic and foreign steel-works in the end of 60th of the previous century. In the process of mastering of CCMs, which were put into operation within the programs of the plant modernization and transferring to BOF production with steel continuous casting, the CCMs were significantly modernized and technology of casting was perfected. To bring down the impact on the solidifying billet peel and decrease a billet swell, the scheme of the supporting rollers location was changed, which enabled to increase the length of the supported zone. A principally new scheme of billets cooling was implemented, which ensured a softer and uniform secondary cooling due to water-air “fog”. To create optimal conditions of axis zone forming during production of round billets of 430 mm diameter, a technology of protective heat screens application was used. The protective screens were installed in the end of ingot solidification zone. A large work was done on determination of optimal technological casting parameters – temperature and speed modes, types of slag forming mixtures, types of heat-insulating mixtures, methods of metal protection in the process of casting. As a result of the work done, at EVRAZ NTMK a complex of steel continuous casting was created, which enables to be flexible depending on the varying situation at the market and to produce continuously casted billets of various dimensions and wide range of steel grades.

Modern status and ways of development of round billet production technology by steel continuous casting

Production of round billets by steel continuous casting, widely used for manufacturing seamless pipes, railway wheels and tyres, quality long rolled products etc., is widely spread in the world steel industry. Constant search for improved design of CCM takes place, separate parts of existing machines are being perfected. An analysis of collected in the world practice experience of solving problems, related to production of round continuously casted billets, enables to choose proper technical solutions for each particular situation, to determine rational parameters of technology. History of development of round continuously casted billets production technology considered. Data on their modern producers presented. Peculiarities of steel continuous casting technology, as well as reasons of defects of round continuously casted billets have been discussed. Classification of basic kinds of cracks of round continuously casted billet presented. Basic problems during production of round continuously casted billets relate to ovality formation, mainly because of unevenness of heat-away in the mold. The increased ovality can lead to formation of internal and external cracks. Ways of solving problems of defects formation and ways of round continuously casted billet technology perfection summarized. Application of methods of mathematical simulation for a technology, which enables to produce defectless billets considered. It was shown, that basic measures to decrease number of billet defects, relate to setting rational parameters of temperature-speed mode, transfer to internal mold profile, corresponding to the billet shrinkage. Another measure is elimination of uneven impact of the liquid metal stream on the solidifying shell in the area of small and big radius. A perspective direction of round continuously casted billets production technology perfection is application of soft reduction methods and electromagnetic stirring of the liquid metal.

The Synergetic Effect of Hot Rolling and Heat Treatment on Mechanical Properties: AISI-1045 and JIS-SUP 9 Steel

Abstract Hot rolling and heat treatment are the two industrial metallurgical applications used with compatible steels to modify mechanical properties. In this article, we studied the combined effect of hot rolling and heat treatment at constant parameters on medium carbon steels with respect to reduced thickness. For this purpose, the precasted round billets (110-mm diameter) of AISI-1045 and the square billet (110 by 110 mm) of JIS-SUP 9 were hot rolled and the thickness was reduced up to 6, 8, and 12 mm and 18, 28, and 45 mm, respectively. The hot rolled billets were subjected to heat treatment. The chemical compositions of the steels were evaluated by optical emission spectroscopy, whereas the microstructures of the samples after hot rolling and heat treatment were observed through metallography. Furthermore, the mechanical properties of the samples were calculated through the tensile test. The results showed a fall in ductility and toughness with respect to reduced thickness and a rise in mechanical strength. It is noteworthy that breaking strength remained unaffected. The JIS-SUP 9 steel is a spring steel, which is the reason for its better mechanical properties (e.g., toughness and ductility) as compared with AISI-1045 steel.

Effect of the Nonuniform Distribution of the Mechanical Properties of Rolled Sheets on the Shape of a Round Billet after Forming in Making Large-Diameter Pipes

The influence of a nonuniform distribution of the mechanical properties of rolled sheet steel on the shape of a pipe billet in making large-diameter pipes in the 1420 pipe-electric welding unit line is studied. The technique and results of measuring the hardness along the perimeter of the initial 25.8 × 4340 × 12 200 mm rolled sheet of strength class K60 are presented. The hardness of the sheet is maximal in the longitudinal direction at the tail end and is minimal at the center. The height and radius of the crimped edge are measured after crimping. The geometric discrepancy in the billet edges along the length is larger than that across the width by 6%. The horizontal and vertical diameters, the gap width, the edge displacement in height, and the diameters at l = 100 mm from the edge end are measured after step-by-step forming. The dependence of the gap width of the pipe billet after forming on the yield strength of the rolled sheet is determined.