Billet Shape Research Articles

Optimizing the shape of the initial billet in the forging of complex rotational parts through the reduced basis method

Optimizing the shape of the initial billet in the forging of complex rotational parts through the reduced basis method

Simulation of BB-2 beam billet conti-nuous casting for production of large-sized I-beams

In connection with expansion of construction sector, it is planned to develop 80‒90‒100 I-beams. For these I-beams, universal section of continuously cast billet BB-2 (1050×450×120) was developed. The purpose of this work was to check casting parameters of given billet in a simulation model, using LVMFlow software, to confirm analytical calculations. Following parameters were chosen as parameters to be evaluated: geometric shape of the cast billet, temperature and dynamic parameters of casting. For maximum reliability, boundary conditions were set similar to real parameters of the CCM-3 at EVRAZ NTMK JSC, however, as assumptions, the calculation was carried out only in zone of direct contact with mold sleeve, and plane deformation condition was set along casting. Simulation results showed possibility of using LVMFlow to simulate the beam blanks casting processes with high degree of convergence. Casting BB-2 billet is technically possible in the conditions of continuous caster No. 3 at JSC EVRAZ NTMK, when the mold is replaced. Hydrodynamic pressure is created only on walls of crystallizer; there is vacuum on remaining surfaces due to lack of crystallizer walls narrowing sleeve towards cooling. Crystallization occurs most slowly along the interface between the wall and the BB flanges, however, there are no defects in the form of splashes, due to the low hydrodynamic pressure in these zones

Simulation of BB-2 beam billet conti-nuous casting for production of large-sized I-beams

In connection with expansion of construction sector, it is planned to develop 80‒90‒100 I-beams. For these I-beams, universal section of continuously cast billet BB-2 (1050×450×120) was developed. The purpose of this work was to check casting parameters of given billet in a simulation model, using LVMFlow software, to confirm analytical calculations. Following parameters were chosen as parameters to be evaluated: geometric shape of the cast billet, temperature and dynamic parameters of casting. For maximum reliability, boundary conditions were set similar to real parameters of the CCM-3 at EVRAZ NTMK JSC, however, as assumptions, the calculation was carried out only in zone of direct contact with mold sleeve, and plane deformation condition was set along casting. Simulation results showed possibility of using LVMFlow to simulate the beam blanks casting processes with high degree of convergence. Casting BB-2 billet is technically possible in the conditions of continuous caster No. 3 at JSC EVRAZ NTMK, when the mold is replaced. Hydrodynamic pressure is created only on walls of crystallizer; there is vacuum on remaining surfaces due to lack of crystallizer walls narrowing sleeve towards cooling. Crystallization occurs most slowly along the interface between the wall and the BB flanges, however, there are no defects in the form of splashes, due to the low hydrodynamic pressure in these zones

CNN-Based Ti-6242 Impeller Forging Process Design for Uniform Strain Distribution

In this study, we propose a systematic process design method using a convolutional neural network (CNN) for the uniform strain distribution of a Ti-6242 impeller during forging. A convolutional neural network (CNN) is a machine learning algorithm optimized for processing grid-like data, such as images, by identifying patterns within the data. To achieve the design goal with a simple process, we propose a methodological process in which the initial billet passes through three steps: upsetting, preform forging, and target impeller forging. We used the CNN model in the upsetting and preforming steps to enable our proposed design method to be applied to various impeller shapes. We trained a CNN model with two different types of datasets: one to derive the preform shape suitable for the target impeller forging and another to determine the shape of the initial billet that was upset for impeller preform forging. The proposed forging process resulted in a reduction in the mean strain, strain standard deviation, and maximum strain by up to 38.6%, 52.5%, and 59.7%, respectively, compared with the impeller forging processes proposed in previous studies. Consequently, the strain of the forged product was been homogenized, thereby reducing the possibility of defects. This process design method can be used in fields such as aerospace that require high-quality forging.

A Preliminary Study on the Quality of Joining AISI 316 and AISI 3415 Steel by the near Solidus Forming Process

In this study, the Near Solidus Forming (NSF) process, which falls under the umbrella of semi-solid processes, was utilized to coforge an AISI 316 tube and an AISI 3415 rod into an as-forged valve geometry. The billet used for the process was kept as large as possible to increase the contact surface area between the two materials. The process was carried out at 1360 °C in a single stroke, almost completely filling the geometry. No joining was observed in areas where low strains were expected, but in regions with medium to high strains, cross-diffusion of 2–7 μm was observed. The presence of small oxide particles was also observed in the joint due to the bimetallic billet shape.

Some specifics of the billet open and submerged stream casting

Experimental series of steel casting were carried out to determine the effect of the continuous casting method on the fre-quency of defects formation in billets. At the same time, the 125x125 mm square billets production was carried out on a six-strand caster with casting speeds of 2.8-4.3 m/min. In the process of research, a series of 5 melts of steel 60 (St60) was initially casted with an open stream. After that, using the same molds, 5 melts of steel 40X were sequentially casted with a submerged stream. As a result of an industrial experiment, it was found that because of the open stream continuous casting the number of rhomboidal billets was 4.5 %. In the case of using the submerged stream technology defects in the billet shape were not observed. The use of the "stopper rod” — "tundish nozzle" — "submerged entry nozzle" system allows to control metal consumption during casting more accurate and timelier in automatic mode without changing the billet casting speed. At the same time, the position of the metal level in the mold is constantly ensured, which most accurately considers the features of the billet solid shell formation over the entire mold length at the current casting speed. The absence of the need to control the casting speed by the level of metal in the tundish makes it possible to maintain the optimal amount of melt in it, which sta-bilizes the casting temperature. The submerged casting prevents bubbling at the phase boundary in the mold and provides the possibility of a significant increase in the nozzle inner diameter (compared to the open stream) that reduces the rate of its clogging with corundum deposits several times. In addition, submerged casting allows the use of special mold powders, which improve the surface quality of the billets. It is possible to additionally improve billets quality using electromagnetic stirring of liquid steel during continuous casting.

Billet Shape and Process Parameters Optimization in Multi-Stage Hot Forging

Billet Shape and Process Parameters Optimization in Multi-Stage Hot Forging

Multi-objective optimization of billet shape and process parameters in multi-stage hot forging

Multi-stage hot forging is a typical manufacturing technology to produce mechanical components with complex shape. In the multi-stage hot forging, flash should always be minimized for material saving, and the uniform deformation is also preferable for high strength of a product. Billet shape directly affects the flash, and it is important to determine the billet shape minimizing the flash. In addition, the process parameters in multi-stage hot forging such as die stroke have an influence on the flash and the uniform deformation. In this paper, the billet shape and the process parameters in multi-stage hot forging is optimized so as to minimize the flash and the equivalent strain. Therefore, multi-objective optimization is performed. The three-dimensional numerical simulation is so intensive that sequential approximate optimization using radial basis function network is adopted for the design optimization. It is found from the numerical result that the trade-off between the flash and the equivalent strain is clarified, and the flash is drastically reduced compared to the conventional billet shape.

逐次近似最適化を用いた熱間多段鍛造におけるプロセスパラメータの多目的最適設計

In the multi-stage hot forging, flash should always be minimized for material saving, and the uniform deformation is also preferable for high strength of a product. In this paper, the billet shape and the process parameters in multi-stage hot forging is optimized so as to minimize the flash and the equivalent strain using sequential approximate optimization. It is found from the numerical result that the trade-off between the flash and the equivalent strain is clarified, and the flash is drastically reduced compared to the conventional billet shape.

Research of technology of manufacturing of steeply curved bends

Purpose of work. Investigation of the features of the technological process of manufacturing curvilinear sections of the pipeline – steeply curved bends.
 Research methods. Three-dimensional modeling of a design of equipment and a finished product; experimental studies of the technology of manufacturing steeply curved bends by pushing through a curved hole of the assembly matrix without using fillers; estimation of deformation by the method of dividing grids.
 Obtained results. Literary sources are analyzed and the main problems arising in the manufacture of steeply curved bends for each method are identified. To study the features of the manufacturing technology, a three-dimen­sional model of the assembly matrix was modeled using the investigated method, the design, dimensions and material of the tooling were selected. Equipment was made. Sizes and material of pipe billets were selected. The operations of the technology for the manufacture of steeply curved bends by pushing through a curved hole of the assembly matrix without the use of fillers were determined.
 Experimental studies of the technology have been carried out. For this, the manufactured stamp was installed on a PG-100A hydraulic press. Pipe billets were placed in a guide sleeve, which was screwed to the assembly die when the press rod was placed in the upper position. The punch pushed the pipe billet along the curved hole of the assembly matrix while moving the rod down. Upon completion of the pushing process, the press rod was in the upper position. For unimpeded removal of the finished product, the guide sleeve was removed, the matrix was unscrewed and removed from the clamps.
 Several samples were obtained, the presence of defects and problems that arose during the formation of steeply curved bends were revealed. To assess the deformation, the method of dividing grids was used.
 Scientific novelty. The method of manufacturing steeply curved bends by pushing an assembly matrix through a curved hole was further developed. The peculiarity of the investigated technology - rejection of the use of expensive filler or rigid mandrels, reduction of technological operations and time for manufacturing a unit of a finished product. As a result of the study, dangerous zones of pipe billets in the process of manufacturing steeply curved bends were identified: the place of bending (crushing, corrugation, rupture) and the ends of the finished product at the exit (ovalization, distortion, breaks).
 Practical value. To prevent the occurrence of dangerous zones during deformation of pipe billets and improve the quality of the finished products obtained, requirements were formulated for the design of the working elements of the developed stamp, the choice of optimal modes of the shaping process, the material and the optimal shape of the pipe billet.

Study of Conditions for Thermal Deformation of Additively Grown Billets from VT6 Titanium Alloy using Finite Element Simulation

This article investigates the hot rolling aspects of a large-sized ring of non-standard, cross-sectional shape, produced from VT6 titanium alloy, and grown using additive technologies (АТ). Finite element (FE) simulation was used to develop the cross-sectional shape and study the parameters of the rolling process. The results enabled the choice of the optimal cross-sectional shape of the ring billet produced by direct laser deposition (DLD), and confirmed the possibility of processing the billet on a ring rolling mill.

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.

Computer-Simulation of the Billet Shape Change during Helical Piercing

In this paper the task of the study of the deformation during helical piercing of the metal was set and solved with the use of the DEFORM-3D software. Methodology, that allows to calculate the length of helix lead along the deformation zone, as well as determine for each lead absolute and relative reduction, the width of the contact area and the metal strain refinement indicator was developed. Based on the developed methodology application the following variation regularities were established: helix lead length (li), quotient reduction (Δr/r0), ratio of the billet radius to the width of the contact area (r0/b), as well as the length of the billet contact surface (l0) with the roll in dependence of the feed angle (β), the roll number of revolutions (N) and the plug nose advancement over the gorge (Cg).

Simulation of Cold Forming of Spur Gears using DEFORM 3D

In the current study, the DEFORM3D program was used to simulation of cold forming of spur gears using lead metal. Three different forms of billets were used to forming the spur gear and the choose of the size of billets was determined according to the size of suggested gear in this study. Analyzes were performed such as effect of stress, strain, average stress, total distance and speed during the formation process. Through the results of the values ​​of the average stresses for the three billets, it was observed that the lowest value is obtained when using a solid billet. As indicated by the results of the study of the maximum stress occurs when the use of hollow billet with a diameter of 4 mm. In the study of effective stress, it was observed that there was a convergence in the stress values ​​for all work pieces; these values ​​in the age zone are greater than the center area. The results obtained from numerical modeling showed that the minimum effective strain occurs when using a hollow billet with a diameter of 4 mm and the highest value when using a solid billet. The velocity of the metal flow is proportional with the shape of the billet, it is noted that the value of the velocity in the case of hollow billets (4 mm and 6 mm) was close together and higher than the value of the metal flow velocity when using a solid billet. The speed of the metal flow is proportional with the amount of the billet cavity; in the case of the hard solid billet the speed is low. Peak load is affected during the formation of the spur gear with the shape of billet; it was observed that the peak load values ​​of the 4 mm hollow billet were less than the peak load of the other two cases.

Quantifying Manufacturability of Component Geometries Using Shape Descriptors

A Do-It-Yourself (DIY) framework of part design and manufacturing is proposed. This framework relies on a digitally indexed part/process-plan library that can enable amateur fabricators in designing and manufacturing complex shapes with similar tolerance as professional counterparts. A methodology to do this is proposed, which involves automated identification of parts from the library that has similar functionality as desired. This step will be followed by automated modification of the corresponding process plans to produce the desired functionality while conforming to design and machine tool requirements. Some challenges associated with setting up such frameworks are realized. These include identifying methodologies for quantifying manufacturability of a final geometry from a starting billet shape using a specified manufacturing process. The utility of spherical harmonic based shape descriptors is analyzed for the same. Shortcomings of this shape descriptor are discussed.

Influences of Friction Condition and End Shape of Billet on Convex at Root of Spline by Rolling with Round Dies

The rolling process is widely used to manufacture high-performance splined shaft components. However, there is a convex at root on free end of spline formed by rolling with round dies. However, the analysis and representation of this forming problem are difficulty due to the complexity of motion and multiplicity of processing parameters. This paper concentrates on the corner filling problem, and a physical analog experiment was designed to investigate the problem. The physical experimental results indicated that the designed experiment can reflect the formation of convex during spline rolling process. The finite element analysis of the physical analog experiment process was carried out to study the influences of friction condition and end shape of billet on convex at root of rolled spline. The results indicated that the height of convex will be reduced with increasing friction condition; the height of convex can be reduced by optimizing the end shape of billet. The results of present study provide a basis for optimizing and controlling the forming quality on free end during spline rolling process.

Control of surface temperature of an aluminum alloy billet by air flow during a heating process at elevated temperature

The procedure of semi-solid forming is composed of heating a billet, forming, compression holding and ejecting step. There are several methods to heat a billet during semi-solid forming process such as electric heating and induction heating. Usually in semi-solid forming process, induction heating has been adopted to achieve more uniform temperature of semi-solid material. Although induction heating is better method than any others, however, there is still difference of temperature between internal part and surface part of semi-solid material. Worse yet, in case of high liquid fraction of semi-solid material, liquid of the billet will flow down though solid of the billet still remains, which is very difficult to handle. In the present study, induction heating of the billet during thixoforging process with forced surface cooling has been performed to obtain more uniform distribution of temperature, microstructure and shape of the billet. Distribution of temperature of the billets was measured and compared with that of conventional distribution of temperature. Microscopic and macroscopic aspects of the billets were discussed according to location of the measuring points. By this new induction heating method, not only temperature distributions over the whole billet become uniform, but also control of temperature distribution between inside and outside part of the billet is possible as user’s experimental intentions.

Анализ напряженно-деформированного состояния в черновых проходах непрерывной прокатки электротехнической меди

The aim of the work is to analyze the stress-strain state in rough rolling in Mannesmann Demag Sack continuous mill. Computer experiments involved the use of DEFORM software package, and the finite element method was used to solve the problem. The change of the billet shape, distribution of the strain degree, strain rate and longitudinal stresses are analyzed. In the fourth rolling pass, the zones of increased strain (up to 1.00 and above) are arranged along the circle arcs adjacent to the roll gap. The highest strain rate (up to 145 s –1 ) is also achieved at the inlet of the deformation zone directly beneath the rolls. It is established that in all rough passes the greatest strain is localized at the outlet of the roll gap near the peripheral zones. The highest strain rate in each investigated pass is observed in contact areas at the inlet of the deformation zone. The largest longitudinal tensile stresses arise at the inlet and outlet of the deformation zone in non-contact areas. At the same time emergence of a large tensile stress on free surfaces during rolling of a rectangular billet in an oval caliber is revealed which can lead to the disclosure of cracks inherited from the foundry process.

Optimization design preform billet shape of 7050 aluminum alloy giant plane forgings based on electric field method and MBC toolbox

The preform billet shape of the 7050 aluminum alloy giant plane forgings has been designed using electric field method based on similarity principle. Firstly, the electrostatic field was analysed by using ANSYS software, from which the preform billet shape was obtained based on electrostatic field equipotential lines. The preform shape, press velocity, temperature and friction factor were taken as parameter variables, while the forming load, filling rate and grain size were chosen as optimization goals. The mathematical model was optimized by the use of a Model-Based Calibration (MBC) toolbox for modelling, Three-Dimensional of Design Environment for FORMing (DEFORM-3D) for simulation and CAlibration GEneration (CAGE) toolbox, obtaining the best preform shape and the optimal combination of process parameters (friction factor μ = 0.2, press velocity ν = 9.8 mm/s and billet temperature T = 478 °C) when the equipotential line was ξ = 0.425 V. Finally, comparing with initial preform shape, the results indicate that the optimized preform billet designed by electric field method has an advantage in finish forging, while the forming load of finish forging reduces by about 38 % and the average micrograin size reduces by about 45 %. Therefore, it provides an effective method for designing preform billet shape of complex forgings.

Fast analysis on metal flow in isothermal local loading process for multi-rib component using slab method

Based on the local loading characteristics and the slab method (SM) models describing the meal flow of T-shaped component under local loading condition, an algorithm for fast analyzing metal flow and cavity fill in local loading process of titanium alloy multi-rib component has been proposed. The key technologies of fast analysis based on SM were explored, such as the description of geometric parameters, definition of calculating area, treatment of dynamic boundary condition, and so on. Based on the above key technologies, an analysis system for local loading process of multi-rib component was developed, and its reliability was verified by finite element simulation. Comparing with the finite element simulation, the computational time by the developed system has been greatly reduced. The reasonable parameter range and initial shape of billet for isothermal local loading process of large-scale rib-web component can be quickly determined by using the developed system, and then the times of three-dimensional finite element simulation can be reduced in the process optimization.