KR20200019459A - Twinning/transformation induced plasticity high entropy steels and method for manufacturing the same - Google Patents

Abstract

According to the present invention, provided are high entropy steel in which twinning and phase transformation are simultaneously performed, and a method of manufacturing the same. The high entropy steel includes three or more alloying elements selected from the following, by atomic percentage: iron (Fe) from 35% to 80%, nickel (Ni) from 5% to 35%, manganese (Mn) from 5% to 35%, cobalt (Co) from 5% to 35%, and chromium (Cr) from 5% to 35%. Moreover, a content of each of the alloying elements does not exceed a content of the Fe.

Description

Strain and phase transformation organic high entropy steel and its manufacturing method {TWINNING / TRANSFORMATION INDUCED PLASTICITY HIGH ENTROPY STEELS AND METHOD FOR MANUFACTURING THE SAME}

The present invention relates to a high-entropy steel exhibiting twin and phase transformation organic plastic properties, and more particularly, twin boundary or phase boundary due to twin and phase transformation interferes with dislocation movement, thereby increasing the work hardening rate and simultaneously increasing strength and ductility. The present invention relates to a high entropy steel and a method of manufacturing the same, which further improve mechanical properties.

With the rapid development of industrial technology, a new class of materials, recently referred to as high entropy alloys as a new alloy system, in order to meet the complex functional requirements that cannot be solved with a single metal. Are being proposed and developed.

The high entropy alloy is an increase in configuration entropy due to the mixing of various elements rather than the formation of a compound due to the reduction of free energy through the formation of intermetallic compounds, thereby reducing the total free energy, thereby reducing the metal between the multicomponent alloy elements. It does not form an intermetallic compound or an amorphous alloy, but refers to an alloy in which a solid solution in which various alloying elements are mixed is formed.

The high entropy alloy has been known through Non-Patent Document 1. In Non-Patent Document 1, a multi-element alloy Fe ₂₀ Cr ₂₀ Mn ₂₀ Ni ₂₀ Co ₂₀ produced in anticipation of the formation of an amorphous alloy or a complex intermetallic compound is formed of a crystalline FCC (Face Centered Cubic) solid solution, which is unexpected. It is an alloy that has become interesting. The high entropy alloy has a peculiar characteristic of forming a single phase even though the existing alloy is mixed with a similar ratio of 4 to 5 or more elemental alloy elements, compared to other alloy elements added to 60 to 90 wt% of the main alloy element. Array entropy by mixing is found in large alloy systems.

As a prior art related to high entropy alloys, there is Patent Document 1 and Patent 믄 heon. The patent document 1 is a multi-metal component and contains five or more metal components containing each element such as V, Nb, Ta, Mo, Ti at a variation of ± 15 atomic% or less, and all added elements are the main elements. High-entropy alloys are disclosed that achieve high hardness and modulus, which consist of single-phase solid solutions of face-centered cubic and / or body-centered cubic structures as a working alloy system. However, Patent Document 1 as described above has a variety of expensive heavy alloy elements are added, there is a difficulty in the manufacturing process due to the melting point difference between the added alloy elements.

On the other hand, Patent Document 2 relates to a high entropy alloy that implements a high hardness produced by the powder metallurgy process of the ceramic phase (typically tungsten carbide) and multi-component high entro alloy powder, the face-centered cubic and / or body-centered cubic structure It is composed of single-phase solid solution of the technology to realize the excellent mechanical properties. However, the said patent document 2 has a problem that manufacture is difficult because a high temperature process is needed when manufacturing an alloy using a ceramic material.

As in Patent Documents 1 and 2, high-entropy alloys using metal or ceramic alloy elements are attracting attention as new materials in the metal field because they have excellent mechanical properties. Recently, various studies have been continued as it is known to exhibit excellent properties even in extreme environmental properties such as high temperature mechanical properties and low temperature mechanical properties. However, since most of the research has been made to evaluate the mechanical and physical properties of the high-entropy alloy composed of the same fraction (Equiatomic) easy to form a high entropy alloy, the improved mechanical properties based on the high entropy alloy Research on the development of alloys to obtain is insufficient.

In addition, if the change of structural and mechanical properties due to the increase of entropy is applied to existing nonferrous and steel materials, it is highly likely that new properties will be induced or the existing properties will be improved. There is no research and invention to improve the characteristics by applying.

United States Patent Application Publication US 2013/0108502 A1 United States Patent Application Publication US 2009/0074604 A1

 Matreial Science and Engineering A, Volumes 375-377, July 2004, page 213-218.  Matreial Science and Engineering A, Volumes 711, January 2018, page 492-497.

One aspect of the present invention is a brittle intermetallic compound by increasing entropy by introducing a solid solution matrix formation concept by the configurational entropy of a high entropy alloy to steel materials, by designing the type and content of various alloy elements in the direction of increasing entropy It is an object of the present invention to provide a high-entropy steel and a method for producing the same, which are excellent in workability and work hardening performance by suppressing the formation of.

Specifically, the twin boundary or phase boundary caused by twin and phase transformation interferes with dislocation movement, thereby increasing the work hardening speed and simultaneously increasing the strength and ductility. do.

In addition, the subject of this invention is not limited to the content mentioned above. The problem of the present invention will be understood from the general contents of the present specification, those skilled in the art will have no difficulty in understanding the additional problem of the present invention.

The present invention for achieving the above object,

In atomic%, Fe: greater than 35% and less than 80%, balance Ni: greater than 5% and less than 35%, Mn: greater than 5% and less than 35%, Co: greater than 5% and less than 35% and Cr: greater than 5% and less than 35% Consisting of three or more selected alloying elements, the content of each of the alloying elements relates to high entropy steel (steel) excellent in workability and work hardening performance does not exceed the content of Fe.

The high entropy steel is in atomic%, C: 0.01 to 5.0%, N: 0.01 to 5.0%, B: 0.01 to 5.0%, Si: 0.01 to 10%, Cu: 0.01 to 10%, V: 0.01 to 10 % And Al: 0.01 to 10% may further include one or more.

The high entropy steel preferably has a lamination defect energy of 40 mJ / m ² or less and an atomic size difference x alloy composition% value of 0.05 or more.

In addition, the present invention,

Preparing a metal material having a composition component as described above;

Manufacturing the prepared metal material into a molten alloy;

A step of homogenizing heat treatment of the prepared alloy at a temperature range of 850 to 1250 ° C., followed by cooling to room temperature; And

After processing the cooled alloy, the second heat treatment to maintain for 0.5 to 72 hours in a temperature range of 350 ~ 850 ℃; High processability and manufacturing process comprising high entropy steel (steel) excellent will be.

The metal material may be manufactured into a molten alloy by using one of a casting, arc melting, powder metallurgy, spray casting, spray coating, spray coating, and 3D-printing methods.

The processing can be any one of forging, extrusion, rolling and drawing.

According to the present invention having the above-described configuration, in contrast to the existing technology, even in the case of low stacking defect energy and high stacking defect energy, twin organic plastic deformation and work hardening, and phase transformation organic work hardening behavior are induced. It is possible to provide high entropy steels with superior mechanical properties and economics as compared to fractional high entropy alloys.

In addition, the high entropy steel of the present invention is greatly improved mechanical properties, it can be applied to offshore plants, extreme environmental structural materials that require excellent toughness and high strength at low temperatures. Increasing the atomic size difference × alloy composition% value causes alloying elements to react with dislocations to induce dislocation transfer or to induce expansion of partial twin dislocations, causing deformation twins, resulting in low lamination energy and high lamination defect energy. Even in the case of twin organic plastic deformation and work hardening behavior can be exhibited. Accordingly, the high mechanical properties through phase transformation organic work hardening can be applied to high temperature materials such as nuclear pressure vessels, cladding tubes, turbine blades for thermal power generation, etc.

1 is a diagram showing a schematic diagram of twin organic alloy design due to the effect of the stacking defect energy and alloy composition of the high-entropy steel of the present invention.
2 is a process flowchart showing a schematic procedure of the manufacturing method of the present invention.
Figure 3 is a photograph observing the microstructure of the invention example 1 of the embodiment of the present invention.
Figure 4 is a photograph observing the microstructure of Example 6 of the present invention, (a) when the strain is 20% strain in the tensile test, (b) shows the microstructure when the strain is 40%.
5 is an XRD analysis graph of the specimen of Inventive Example 1 in Examples of the present invention, (a) before the stretching process, and (b) is an XRD analysis graph after the stretching process.

The inventors of the present invention have recently conducted research on the development of new materials exhibiting high strength and high ductility mechanical properties in order to solve problems such as rising raw material prices due to resource limitations and stricter environmental problems such as greenhouse gas. As a result, the concept of high entropy alloy is introduced to steel materials, and various alloy elements are designed in the direction of increasing entropy, thereby suppressing the formation of brittle intermetallic compounds by increasing entropy, thereby improving workability and work hardening performance. It is to confirm that it can provide an excellent high entropy steel and to present the present invention. That is, the present invention provides a high-entropy steel that can realize excellent strength and ductility compared to general high-entropy alloys by increasing the speed of work hardening by preventing the displacement of twin or phase boundaries caused by twin and phase transformation. do.

Therefore, the present invention is in atomic%, Fe: more than 35% and 80% or less, balance Ni: more than 5% and 35% or less, Mn: more than 5% and 35% or less, Co: more than 5% and 35% or less and Cr: 5% Consists of three or more alloying elements selected from more than 35%, the content of each alloy element relates to a high entropy steel excellent in workability and work hardening performance does not exceed the content of Fe.

Hereinafter, the high entropy steel of the present invention will be described in detail. First, the composition of the high entropy steel of the present invention and the reason for limiting the content thereof will be described in detail.

The high entropy steel of the present invention is, in atomic%, Fe: more than 35% up to 80%, balance Ni: more than 5% up to 35%, Mn: more than 5% up to 35%, Co: more than 5% up to 35% and Cr: It comprises three or more alloying elements selected from more than 5% and less than 35%, each of the alloying elements does not exceed the content of Fe.

Fe, Ni. Mn, Co, and Cr are elements constituting a high entropy alloy, and are a four-cycle transition element group, and are suitable for forming a solid solution with a small difference in atomic radius. The Mn and Ni are elements for promoting a face-centered cubic (FCC) solid solution, Co is finer structure, Cr is improved corrosion resistance.

The reason why the Fe content in the element is more than 35% and less than 80% is to maximize entropy as much as possible, but to make the component of Fe higher than each other element so that the matrix has the characteristics of steel.

The Ni content is more than 5% and less than 35% to maximize entropy, but the base has the characteristics of FCC. The Mn content is more than 5% and less than 35% is maximized entropy, but lowers the stack defect energy of the matrix. The purpose of the FCC is to have the characteristics of the Co content of more than 5% and less than 35% to maximize entropy, but to optimize the microstructure and phase transformation organic tissue, and the Cr content is more than 5% and less than 35% To maximize the corrosion resistance.

As described above, the high-entropy steel of the present invention, unlike the existing high-entropy alloy that includes a selection of five alloy elements of Co, Cr, Fe, Mn, Ni, essentially contains Fe and remaining four elements Including three or more of these, it is made so that the content of Fe is greater than the content of other added elements. Therefore, increasing the atomic size difference x alloy composition% value causes alloying elements to react with dislocations to induce dislocation movement or to induce expansion of partial twin potentials, resulting in strain twins. Even in the high case, it can show twin organic plastic deformation and work hardening behavior.

In addition, the high entropy steel of the present invention is atomic%, C: 0.01 to 5.0%, N: 0.01 to 5.0%, B: 0.01 to 5.0%, Si: 0.01 to 10%, Cu: 0.01 to 10%, V: 0.01 to 10% and Al: 0.01 to 10% may further include one or more.

C, N, and B are invasive elements, and Si, Cu, V, and Al are substituted elements to react with dislocations or twin partial potentials to induce twin and phase transformations. Increase the work hardening rate of the material.

In the present invention, the content of C, N and B is limited to 0.01 to 5%, respectively, when the content of these elements is less than 0.01%, when the reaction stress with the potential is too small and exceeds 5%. This is because the lattice warpage is severe and embrittles the base beyond the solid solution limit, reducing the efficiency of reaction with dislocations.

The Si, Cu, V, and Al have a large difference in atomic radius from Fe, Cr, Ni, Mn, and Co, which are the main elements forming a high entropy steel, and have a large difference in valence and segregation at a potential. As a result, twinning and phase transformation are induced by interfering with dislocation movement and partial dislocation coupling. Accordingly, twin boundary or phase boundary impedes movement of dislocation to increase work hardening speed.

In the present invention, the content of Si, Cu, V and Al of 0.01 to 10%, respectively, is less than 0.01% segregation and reaction effect with the potential is too small, when it exceeds 10%, if more than 5% In this case, the lattice distortion is severe and embrittles the base beyond the solid solution limit, and the efficiency of reaction with dislocations decreases.

As described above, the high-entropy steel of the present invention is based on a component containing more than 35% of Fe and 80% or less, and at least one of Ni, Mn, Co, and Cr. In order to include one or more additive elements selected from C, N, B, Si, Cu, V and Al. These additive elements are segregated to potentials to hinder / suppress the movement of full potentials or twin partial potentials to induce strain twins, and not only when the stacking fault energy (SFE) is low but also the atomic size misfit of the additional elements is large. Even in this case, the deformation twin is activated, so that work hardening and twin organic plastic deformation behavior can effectively occur.

Hereinafter, the work hardening of the high entropy steel of the present invention and the resulting strength and ductility increase mechanism will be described.

FIG. 1 shows a schematic diagram of a twinned organic alloy design by the influence of the stacking defect energy and the alloy composition of the high entropy steel of the present invention.

 As shown in FIG. 1, the high stacking defect energy region shows Wavy slip, and as the atomic size difference x alloy composition% value increases, alloying elements react with the potential to induce dislocation shift or induce expansion of partial twin potentials. In this case, the material with low lamination defect energy and high lamination defect energy are changed from the Wavy slip region to the planar slip region and the TWIP region. As described above, the high entropy alloy having low lamination defect energy may increase the work hardening rate by preventing the transition of twin or phase boundary due to twin and phase transformation, thereby exhibiting superior strength and ductility than the high entropy alloy.

Preferably, in the present invention, when the lamination defect energy is 40 mJ / m ² or less, atomic size difference x alloy composition% value is 0.05 or more, it provides a high entropy steel exhibiting excellent strength and ductility through the work hardening mechanism as described above can do.

Next, the manufacturing method of the high entropy steel of this invention is demonstrated in detail.

The high entropy steel manufacturing method of this invention is a process of preparing the metal material which has a composition component as mentioned above; Manufacturing the prepared metal material into a molten alloy; A step of homogenizing heat treatment of the prepared alloy at a temperature range of 850 to 1250 ° C., followed by cooling to room temperature; And after the cooled alloy is processed, a secondary heat treatment for maintaining 0.5 to 72 hours in a temperature range of 350 to 850 ° C.

2 is a process flowchart showing a schematic procedure of the manufacturing method of the present invention.

As shown in FIG. 2, in the present invention, in atomic%, Fe: more than 35% and 80% or less, balance Ni: more than 5% and 35% or less, Mn: more than 5% and 35% or less, Co: more than 5% A metal material comprising at least three alloy elements selected from 35% or less and Cr: more than 5% and 35% or less, wherein the content of each alloying element does not exceed the content of Fe is prepared.

In the present invention, the metal material is atomic%, C: 0.01 to 5.0%, N: 0.01 to 5.0%, B: 0.01 to 5.0%, Si: 0.01 to 10%, Cu: 0.01 to 10%, V: 0.01 to 10% and Al: It may further comprise one or more of 0.01 to 10%.

The melting process is for alloying the produced metal material, the present invention is not particularly limited to the method, it is based on the method usually carried out in the technical field to which the present invention belongs. For example, the alloy may be manufactured by casting, arc melting, powder metallurgy, spray casting, spray coating, spray coating, 3D-printing, or the like.

Next, the prepared alloy is subjected to homogenization heat treatment. Since the high entropy steel is mixed with various elements, a homogenization heat treatment is performed to induce sufficient diffusion. The homogenization heat treatment is preferably maintained for 1 to 48 hours in the temperature range of 850 ~ 1250 ℃.

Subsequently, the homogenized heat-treated alloy is cooled to room temperature. In this invention, since it does not specifically limit to the said cooling system, Various systems, such as water cooling, oil cooling, and air cooling, can be used. Through the cooling process, some metal components not dissolved in the matrix structure in the microstructure may be uniformly distributed.

In the present invention, the cooled alloy is processed. In the present invention, methods such as forging, extrusion, rolling, drawing and the like can be used as such processing methods. This processing can introduce various deformation defects into the cooled alloy material.

Subsequently, the present invention performs a secondary heat treatment for maintaining the cooled alloy for 0.5 to 72 hours in the temperature range of 350 ~ 850 ℃. This secondary heat treatment process is a process for uniformly depositing phase transformation precipitates of various shapes due to twin and phase transformation at the base, and manufacturing a microstructure in which phase transformation precipitates of various shapes due to twin and phase transformation are simultaneously present in the solid phase matrix structure of the single phase. can do.

Subsequently, in the present invention, the secondary heat treated steel alloy is cooled to room temperature, and various cooling methods such as water cooling, oil cooling, air cooling, and furnace cooling may be used.

Hereinafter, the present invention will be described in detail through examples.

(Example)

First, high entropy steels of Comparative Examples 1 and 2 and Inventive Examples 1 to 14 were prepared as shown in Table 1 below.

Specifically, a metal material having a composition (atomic%) shown in Table 1 below was prepared, and an alloy was prepared by arc melting in a vacuum atmosphere. Thereafter, the homogenization heat treatment was performed at 1050 ° C. for 24 hours, and then cooled to room temperature. Subsequently, the cooled alloy was subjected to secondary heat treatment at 850 ° C. for 10 minutes after rolling to promote grain refinement, and then cooled to room temperature to produce a final high entropy steel.

On the other hand, for the high entropy steel produced as described above made a plate of 1mm thickness, performing a tensile test to evaluate the mechanical properties of the results are shown in Table 1 below. Atomic size difference x alloy composition% value and lamination defect energy were measured and are also shown in Table 1.

division alloy Stacking fault energy
(mJ / m ² ) Atomic Size Difference x Alloy% The tensile strength
(MPa) Yield strength
(MPa) Elongation
(%) Comparative Example 1 Co ₂₀ Cr ₂₀ Fe ₂₀ Mn ₂₀ Ni ₂₀ 35   N.A. 496 336 68 Comparative Example 2 Co ₂₅ Ni ₂₅ Fe ₂₅ Mn ₂₅ 33   N.A. 784 532 60 Inventive Example 1 Fe ₆₀ Cr _18.8 Ni ₁₀ Co ₁₀ C _1.2 38 0.1908 1000 570 59 Inventive Example 2 Fe ₆₀ Cr _18.8 Ni ₁₀ Mn ₁₀ N _1,2 36 0.1932 1040 630 63 Inventive Example 3 Fe ₆₀ Cr ₁₀ Co _18.8 Mn ₁₀ B _1,2 35 0.1352 896 492 48 Inventive Example 4 Fe ₆₀ Co ₁₅ Ni ₁₀ Mn ₁₀ Cu ₅ 34 0.5280 1152 672 69 Inventive Example 5 Fe ₆₀ Cr ₁₅ Ni ₁₀ Co ₁₀ Si ₅ 33 0.3515 1032 612 60 Inventive Example 6 Fe ₆₀ Cr ₁₅ Ni ₁₀ Mn ₁₀ Al ₅ 36 0.3235 1096 636 62 Inventive Example 7 Fe ₆₀ Cr ₁₅ Ni ₁₀ Co ₁₀ Al _4.5 N _0.5 35 0.3190 1080 696 68 Inventive Example 8 Fe ₆₀ Cr ₁₅ Co ₁₀ Mn ₁₀ Cu _4.5 C _0.5 34 0.4880 1128 738 70 Inventive Example 9 Fe ₆₀ Co ₁₅ Ni ₁₀ Mn ₁₀ Si _4.5 B _0.5 33 0.3195 1072 609 65 Inventive Example 10 Fe ₆₀ Cr ₁₉ Ni ₁₀ Mn ₁₀ N _0.5 C _0.5 34 0.4110 1100 642 67 Inventive Example 11 Fe ₆₀ Cr ₁₅ Mn ₁₀ Co ₁₀ V ₅ 38 0.3215 1128 657 69 Inventive Example 12 Fe ₆₀ Cr ₂₀ Ni ₁₀ Co ₁₀ 36 0.0694 1032 627 65 Inventive Example 13 Fe ₆₀ Cr ₂₀ Mn ₁₀ Co ₁₀ 37 0.0842 1000 597 63 Inventive Example 14 Fe ₆₀ Mn ₂₀ Ni ₁₀ Co ₁₀ 35 0.0687 1016 588 59

As shown in Table 1, in the case of the invention examples 1 to 14 satisfying the composition of the present invention, the phase transformation precipitates of various shapes due to twins, phase transformation in the solid-phase matrix structure of the single phase is superior to the comparative example and It can be seen that the ductility can be balanced. Specifically, compared with Comparative Examples 1 and 2, the high entropy steel of the present invention showed that the twin boundary or phase boundary caused by twin and phase transformations in the matrix prevents the movement of dislocations due to deformation of the solid solution matrix of the single phase. By increasing, it can be confirmed that excellent strength and ductility compared to the existing high entropy alloy can be secured.

On the other hand, Figure 3 is a photograph observing the microstructure of the invention example 1 of the embodiment of the present invention. As shown in Figure 3, it can be seen that the deformation twin is formed in the matrix.

In addition, Figure 4 is a photograph observing the microstructure of Example 6 of the present invention, (a) when the strain is 20% strain in the tensile test, (b) shows the microstructure when the strain is 40%. As can be seen in Figure 4, it can be seen that the second phase due to the modified organic phase transformation, the second phase also increases as the amount of deformation increases.

5 is an XRD analysis graph of the specimen of Inventive Example 1 in Examples of the present invention, (a) before the stretching process, and (b) is an XRD analysis graph after the stretching process. As shown in FIG. 5, Inventive Example 1 had a matrix of single-phase face-centered cubic structure before stretching, but after the stretching, BCC and HCP peaks were observed on XRD data, indicating that a second phase due to phase transformation existed. You can check.

As described above, in the detailed description of the present invention has been described with respect to the preferred embodiment of the present invention, those skilled in the art to which the present invention pertains various modifications without departing from the scope of the present invention Of course it is possible. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the claims below but also by the equivalents thereof.

Claims (7)

In atomic%, Fe: greater than 35% and less than 80%, balance Ni: greater than 5% and less than 35%, Mn: greater than 5% and less than 35%, Co: greater than 5% and less than 35% and Cr: greater than 5% and less than 35% Consists of three or more selected alloying elements, the content of each alloying element does not exceed the content of Fe, high entropy steel with excellent workability and work hardening performance.
The method of claim 1, wherein the high entropy steel is in atomic%, C: 0.01 ~ 5.0%, N: 0.01 ~ 5.0%, B: 0.01 ~ 5.0%, Si: 0.01 ~ 10%, Cu: 0.01 ~ 10% , V: 0.01 to 10% and Al: 0.01 to 10% of the high entropy steel excellent in workability and work hardening performance further comprising.
The high entropy steel of claim 1, wherein the high entropy steel has a lamination defect energy of 40 mJ / m ² or less and an atomic size difference x alloy composition% value of 0.05 or more.
In atomic%, Fe: greater than 35% and less than 80%, balance Ni: greater than 5% and less than 35%, Mn: greater than 5% and less than 35%, Co: greater than 5% and less than 35% and Cr: greater than 5% and less than 35% Comprising three or more selected alloying elements, wherein the content of each alloying element is prepared so as not to exceed the content of Fe prepared metal material;
Manufacturing the prepared metal material into a molten alloy;
A step of homogenizing heat treatment of the prepared alloy at a temperature range of 850 to 1250 ° C., followed by cooling to room temperature; And
After processing the cooled alloy, the secondary heat treatment for maintaining for 0.5 to 72 hours in a temperature range of 350 ~ 850 ℃; high processability and manufacturing process excellent high-entropy steel.
The method of claim 4, wherein the high-entropy steel is in atomic%, C: 0.01 to 5.0%, N: 0.01 to 5.0%, B: 0.01 to 5.0%, Si: 0.01 to 10%, Cu: 0.01 to 10% , V: 0.01 to 10% and Al: 0.01 to 10% of the high-entropy steel manufacturing method excellent in workability and work hardening performance, characterized in that it further comprises.
The method of claim 4, wherein the metal material is made of a molten alloy by using one of the following methods: casting, arc melting, powder metallurgy, spray casting, spray coating, spray coating and 3D-printing method. High entropy steel manufacturing method with excellent workability and work hardening performance.
The method of claim 4, wherein the processing is any one of forging, extrusion, rolling, and drawing.

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