The intelligent manufacturing of high-performance alloys necessitates computational frameworks capable of bridging the complex gap between industrial processing, microstructure, and properties. In this study, an integrated computational framework is presented to optimize the process-structure-property relationships in M42 high-speed steel (HSS). The framework synergizes furnace computational fluid dynamics (CFD), hot-working finite-element (FE) simulations, calculation of phase diagrams-diffusion-controlled transformations (CALPHAD-DICTRA) modeling, and machine learning (ML) techniques to predict microstructure evolution throughout the entire hot-working process. Experimental validation demonstrates a temperature-prediction accuracy exceeding 85%. Furthermore, ML-driven optimization forging schedule reduced the number of forging passes from 22 to 19 while eliminating cracking risks, resulting in an 8.3% increase in compressive strength (from 4.8 to 5.2 GPa) and a 2.3 HRC enhancement in hardness. Additionally, DICTRA simulations accurately predicted the dissolution kinetics of M2C carbides, showing high consistency with experimental observations. This approach establishes a reliable digital thread for HSS manufacturing, significantly enhancing carbide homogeneity and mechanical performance while providing a systematic pathway for the intelligent design of advanced alloys.

Photovoltaic mounting structures operate in harsh environments, demanding high strength and elongation. However, a strength–graded product series within the same composition is lacking. Through Ti microalloying and heat treatment, we developed steels with strengths of 500–800 MPa and studied annealing effects at 640–740 °C. Scanning Electron Microscope (SEM) shows ferrite and cementite: with increasing temperature, ferrite changes from elongated to equiaxed via recovery and recrystallization, while cementite remains finely dispersed along grain boundaries. Transmission Electron Microscope (TEM) reveals TiC precipitates, which decrease in number but increase in size at higher temperatures. Grain refinement strengthening, dislocation strengthening, and precipitation strengthening are the primary strengthening mechanisms, contributing 91.2% and 94.4% to the yield strength after annealing at 640 °C and 720 °C, respectively. Within a wide annealing temperature range, the tensile strength fully covers the 550–650–750–800 MPa grades, with the corresponding elongation fluctuating between 12.4% and 25.3%, achieving a good strength–ductility balance. In summary, simply adding a single Ti element and adjusting the annealing temperature allows for the production of test steels with strengths ranging from 500 to 800 MPa and matched elongation. This approach not only reduces costs but also provides experimental evidence for the process development of a series of new steels for photovoltaic mounting brackets.

This work uses high-energy synchrotron X-ray diffraction (HEXRD), atomic force microscope (AFM), nanoindentation and EBSD technology to explore a new method for measuring residual stress in strong R {124} 211 texture alloys, and the distribution of residual stress and Young's modulus in different crystal orientations. Compared with the traditional Voigt and Reuss model, for the textured Cu-Ni-Si-Co alloy, a local Voigt and Reuss inter-grain interaction model based on HEXRD diffraction technology is established, which can more accurately characterize the residual stress of superficial layer (230 mu m). The local stress model provides a new X-ray diffraction method for testing the residual stress of textured materials. Aiming at the textured Cu-Ni-Si-Co alloy with compressive stress, the quasi-in-situ method combining EBSD and nanoindentation is used to characterize the residual stress of different crystal orientations in the microdomain. The hard orientation [1 1 1] grain direction has the highest residual stress, and the soft orientation [100] grain direction has the lowest residual stress, and the residual compressive stress in the hard orientation is about twice that of the soft orientation. In addition, the Young's modulus of the material is also the largest on [111] hard-oriented grains and the smallest on [100] softoriented grains.

Ultra-high strength steel can significantly improve the safety and lightweight of vehicles, especially for the closed-profile components. In this study, a novel process simulation of multi-step tube hot metal gas forming (HMGF) of a V-shape torsion beam is conducted. The aim of this paper is to provide the insight into the influence of process variables, such as pre-heating condition, gas pressure and tool temperature, on the formability, hardening and component behavior. The press hardening steel used is hot-rolled BR1500 steel and the stress-strain relationships under different temperatures are investigated for the thermo-mechanical simulation. A consistent simulation model with all relevant sub-stages is then established in LS-DYNA software. Component geometry, wall thinning, hardness and microstructure distributions are achieved in the simulation and the forming parameter dependency is analyzed. And the forming equipment is introduced. The hot gas forming step is the most complicated process, and is carried out in a nitrogen gas environment, which prevents oxidation of the parts after heating.

The relationship between the microstructure and properties of the different orientations of a Cu–Ni–Si–Co alloy was investigated by tensile testing, X-ray diffraction electron backscattering diffraction, transmission electron microscopy, and high-energy X-ray diffraction (HEXRD). The results revealed that the cold-rolled alloy contained mainly a Brass {110}<112> and R {124}<211> texture. The alloy was aged, and it exhibited mainly an R texture, and its volume and distributing width were 45.2% and 10.8°, respectively. The aged alloy exhibited obvious anisotropy, and its tensile strength and electrical conductivity in the rolling direction were 870 MPa and 50% IACS, respectively. In the Cu–Ni–Si–Co alloy, the orientation grains close to the [111] crystal plane were in the hard orientation zone, the Schmid factor value was low, and the material strength was relatively high. At the same time, the [111] crystal plane was close-packed and exhibited good conductivity. The oriented grains close to the [100] crystal plane was in the soft oriented zone and had lower strength and conductivity. Through HEXRD analysis, it was found that the oriented grains with a high twin stacking-fault probability had lower stacking fault energy, and the probability of aging-induced twinning was high.

以某钢厂LX82A帘线钢热轧线为研究对象,建立了基于有限差分法的高速线材轧制过程中温度场的数学计算模型,得到了轧件横断面上各点的温度场分布规律以及轧件表面、芯部等关键点的温度—时间历程曲线、温度—距离历程曲线.同时,分析了开轧温度、终轧速度和轧辊直径对轧制过程温度的影响.经验证,模拟值与实测值误差在±10℃以内,预测准确度良好.

Manufacturing process of pearlitic steel wires involves multiple steps, generating numerous influencing parameters for tensile strength. Therefore, it is difficult to build globally-optimized tensile strength model by costly, time-consuming experimental trials or physical theoretical calculations. Here, a new strategy combining machine learning with multiscale calculation was promoted to construct tensile strength model based on high-dimension, small-size industrial datasets. Process space was transformed to microscopic structure space by thermodynamic, kinetic and finite element calculations, which was then fed to machine learning algorithms. Gradient Tree Boosting and Gaussian Process models show excellent prediction accuracy with maximum relative error less than 2.0 %. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

When the texture is present in the sheet, it is extremely difficult to test the residual stress based on the X-ray diffraction method. Based on the two extreme traditional Voigt and Reuss models, this paper proposes two specific corresponding local models (local Voigt and local Reuss) for the measurement of the plane residual stress of cold rolled sheet texture materials. The residual stress test results of CuNiSi specimen using these two local models show that the proposed local models are credible and can accurately characterize the residual stress in the specimen. In addition, based on the X-ray diffraction sin(2) psi method of the classic residual stress test, a weighted average residual stress calculation method is proposed for cold-rolled texture materials. The d(psi)-sin(2)psi method was used to analyze the effect of texture on residual stress. The results show that the copper texture C{211} < 111 > in CuNiSi specimen has the effect of concentrating the residual compressive stress in the region. The stress increased by about 50 MPa. However, the effect of brass texture B{011} < 211 > and R texture R{011} < 211 > on residual stress was not obvious.

Abstract The effect of cooling rate on the microstructure of SGLX82A steel was systematically investigated by coupling of experimental characterizations and thermodynamic/ kinetic calculations. The as-received casting ingots were heated and hot-deformed using a Gleeble simulator before being subjected to continuous cooling with rates of 5, 10, 15 and 20 K s-1. The microstructure of the SGLX82A steel was analyzed by using laser scanning confocal microscopy and scanning electron microscopy. The homogeneous microstructure with different proeutectoid ferrite fraction, pearlite colony size as well as pearlite lamellar spacing was examined at varied cooling rate. The calculation of the para-equilibrium phase diagram was performed by using Thermo-Calc software, while the DICTRA module was applied to calculate the diffusion-controlled ferrite formation and pearlite growth. Based on the calculations, the deviation between equilibrium and realistic eutectoid point was well explained, and the detected small amount of proeutectoid ferrite was attributable to the short duration before pearlite transformation. For the calculated pearlite lamellar spacings, good agreement was obtained compared with the experimental determinations. In addition, the present thermodynamic/kinetic method was also valid for a Crmodified steel SWRS87B, indicating the composition, processing parameters and microstructure of pearlitic steels can be reasonably designed with the aid of the present computational techniques.

The effects of loop-laying temperature and austenite deformation on the phase transformation behavior during continuous cooling, microstructure, and pearlite interlaminar spacing in 82B steels were investigated. Static and dynamic continuous cooling transformation (CCT) diagrams were measured with a Gleeble-3500 thermal simulator, and the mechanisms governing changes in the initial temperature, initial time, and duration of the phase transformation zone were also analyzed and discussed. The results show that CCT diagram shifted to the bottom right, the initial temperature of the phase transition decreased, the initial time of the phase transition increased, the duration of the phase transition increased, and the lamellar spacing of pearlite was finer as the loop-laying temperature increased. The initial phase transition time decreased, and the phase transition duration first reduced, then increased, and finally decreased in the static condition and in the dynamic condition at 850 °C as the cooling rate increased. Meanwhile, the phase transition duration continuously decreased in the dynamic condition at 900 °C. At a given loop-laying temperature, the lamellar spacing in pearlite was finer due to austenite deformation compared with the undeformed case. Compared with the results shown in the dynamic CCT diagram, the corresponding phase diagrams of the static CCT diagram slightly shifted to the bottom right. Moreover, there was a clear linear relationship between the reciprocal of the lamellar spacing in pearlite and the average undercooling degree in the phase transformation zone.

为了研究薄板带材在连续退火过程中屈曲起皱规律,采用非接触式网格应变仪作为薄板起皱高度测量设备,设计了不均匀拉伸试验.试验可以准确获得试样中心起皱高度与拉伸时间、拉伸载荷的对应曲线,并可观测到试样在拉伸过程中的起皱行为及其发展过程.通过对比发现,夹持端形状为梯形的试样达到临界起皱状态所需的拉伸载荷低,且在夹持端不易产生应力集中,比夹持端为矩形的试样更适合用于测试塑性差的材料.通过试验发现,试样的长度和厚度对带材屈曲临界载荷和起皱临界载荷有十分重要的影响,当试样长宽相等且厚度较薄时,带材更容易起皱.

The disadvantages of poor corrosion resistance and delayed fracture resistance of high-strength medium-carbon spring steel have significantly limited its application in the construction industry. Therefore, there is a need to improve these characteristics of spring steel. In this paper, the effects of Ti, Cu, and Ni on the microstructure, mechanical properties, corrosion resistance, and hydrogen-induced delayed fracture behaviour of spring steel were investigated by scanning electron microscopy, transmission electron microscopy, electrochemical workstation analysis, neutral salt spray test and hydrogen permeation testing methods. The results showed that the tensile strength of the experimental steel reached 2000 MPa and the yield strength reached 1800 MPa. These values were observed when the quenching and tempering temperatures were 900 degrees C and 350 degrees C. respectively; further, the experimental steel had a tempered martensite microstructure at these temperatures. Ti increased the self-corrosion potential of the experimental steel and reduced the self-corrosion current. With an increase in the content of alloying elements (Ti, Cu, and Ni), the depth of the corrosion pits in the experimental steel became shallower and the degree of surface damage was reduced. Moreover, Ti could refine the crystal grains, TiC had high a trap activation energy of hydrogen, and Ti-containing steel had better hydrogen-induced fracture resistance. (C) 2019 Elsevier Ltd. All rights reserved.

The relationship between textures and properties of Cu-Ni-Si alloys was analyzed in this paper. The texture evolution of high strength and high elasticity Cu-Ni-Si alloy in different cold rolling and heat treatment processes was researched by the fiber analysis. And the electrical conductivity and tensile strength in different directions of the Cu-Ni-Si alloy were measured. The results showed that there were mainly Brass texture B{011}<211>，Gauss texture G {011}<100> and Copper texture C {211}<111> in the cold-rolled Cu-Ni-Si alloy. With the increase of cold deformation, the Copper texture was weakening, while the Gauss texture and Brass texture increased. When the deformation was 65%, there was almost no Copper texture in the alloy, and only Gauss and Brass texture exist. After the solid solution and aging process, both the Gauss and Brass texture were weakening, while the S texture {123}<624> increased greatly. After 4 hours aging the conductivity was up to 42.7% IACS. And the tensile strength of different directions is 745.5MPa (0°direction,RD), 684.5MPa (90°direction,TD) and 653.5MPa (45°direction) respectively. Based on the above results, maximum Schmid factor of different textures in different directions and the Index of Plane Anisotropy (IPA) were been analyzed.

The transition metal silicide X3Si (X = V, Nb, Cr, Mo and W) was characterized by its low density, high melting point, high temperature hardness, high temperature resistance to wear, high temperature oxidation resistance and corrosion resistance in this paper. For the fields such as aerospace, gas turbine etc, with the application of a new generation of high temperature structural materials, transition metal silicide will be one of their candidate materials. The stability, crystal structure, mechanical properties, electronic properties, Debye temperature and hardness of X3Si(X=V, Nb, Cr, Mo and W) compounds were calculated employing electronic density functional theory (DFT) and the generalized gradient approximation (GGA). The results show that the remaining silicides have stable structures except that W3Si is a metastable structure in X3Si compounds. Based on the stress-strain theory, the bulk modulus, shear modulus, Young's modulus and Poisson's ratio of Cr3Si and Mo3Si were estimated by Voigt-Reuss-Hill method: 248.7 GPa, 158.9 GPa, 393.0 GPa, 0.24 and 249.2 GPa, 134.6 GPa, 342.1 GPa, 0.27. According to the state density (DOS) analysis, we can see that the valence band of X3Si compound is a combination of covalent bond and metal bond. The temperature of Debye of Cr3Si (645.1 K) in X3Si compound is the highest. The hardness of these silicon compounds is evaluated using a semi empirical hardness theory and the result shows that Cr3Si (10.96 GPa) is the hardest compound among them.

To study the effect of isothermal temperature and cooling rate on the phase transformation and microstructure evolution in SWRH82B steels, a thermal dilatometer was used in this study to generate the static continuous cooling transformation (CCT) and isothermal-transformation thermal-expansion diagrams. In addition, scanning electron microscopy was used to analyze the effect of process parameters on microstructural transformation in the steel specimens. The results suggest that with a decrease in the isothermal temperature, the incubation time and duration of phase transformation gradually decreased; further, the content of non-lamellar pearlite in the microstructure gradually increased at room temperature. Compared with the time-temperature-transformation (TTT) diagram of SWRH82B steel subjected to conventional process conditions (rapid cooling before isothermal treatment), the incubation periods observed in this study were significantly shorter. When the loop-laying temperature was 850 °C, austempering temperature was 630 °C, and cooling rate was 5 °C s−1, the incubation time and phase-transformation duration of the experimental steel were 9.60 and 28.52 s, respectively. With an increase in the cooling rate, the incubation period gradually increased, while the phase-transformation duration initially increased and then decreased. The room-temperature microstructure, obtained by austempering at 630 °C for 300 s, was mainly composed of well-distributed lamellar pearlite. With an increase in the cooling rate, the pearlite interlaminar spacing gradually reduced. However, the room-temperature microstructure, obtained by austempering at 550 °C for 300 s contained a large proportion of non-lamellar structures and the distribution of pearlite became disorganized.

带倒角的结晶器能够改善连铸板坯角部在矫直段的高温延展性,显著减少角横裂的发生.然而,连铸坯的倒角对粗轧过程宽展量有很大影响.通过建立粗轧过程板坯形变的有限元仿真模型,系统研究了轧制过程中板坯倒角尺寸和形状对轧件宽展量的影响.结果表明,连铸坯倒角边长越大,相同的立辊侧压量下所产生的狗骨回展量越小,同时在水平轧制时所产生的自然宽展也越小,而倒角角度的变化对粗轧宽展的影响不显著.针对现有的宽展公式没有考虑轧件存在倒角的问题,给出了一个含有倒角参数的修正项公式.通过与现场实测数据和原宽度模型计算结果对比,对于带倒角的连铸坯轧制情况,修正后的宽展模型预报精度显著提高.

The maximum potential can be discovered by controlling the texture’s species and components for high strength and high elasticity and high conductivity Cu-Ni-Si materials. Texture composition and evolution of Cu-Ni-Si alloy at different cold-rolling deformations was investigated by means of the inverse pole figure and the crystal orientation distribution function (ODF). The microstructural inhomogeneities, such as microbands and twinning in Cu-Ni-Si rolling have been studied, and the deformation processes and their contributions to the rolling textures have also been analyzed. The results showed that the cold rolled texture contained Brass orientation (mainly {211} <111>), S orientation (mainly {123} <634>), Goss orientation and Copper orientation. In addition, Copper orientation transformed to Brass orientation with the increase of cold reduction rate. When the reduction rate was 40%, there appeared a large number of microbands. While the reduction rate increased to 80%, there occurred plenty of twinning/matrix layered structures and the crystal orientation mainly gathered close to B{011} <211> orientation. The formation of microbands caused no severe texture change. However, twinning was responsible for the transit of texture type. The high cold-rolling deformation was beneficial to the formation and development of twinning and Brass texture, and the low cold-rolling deformation was beneficial to the formation and development of microbands and Copper texture.

The finite element analysis software ANSYS was employed to simulate and analyze the electromagnetic induction heating process in the hot metal gas forming process .A finite element model of temperature field coupled with electromagnetic field had been established based on induction heating theory including Maxwell equations and temperature differential equation .Simulation results showed that with the increase of current frequency of electromagnetic induction coil , under the same heating time , temperature rising rate of steel tube increased continuously ,and the final temperature was raised further .With the increase of the current density of electromagnetic induction coil ,under the same heating time and current frequency of electromagnetic induction coil , temperature rising rate of steel tube increased continuously ,heating efficiency was improved effectively ,and the final temperature was raised gradually .With increase of interval space between steel tube and electromagnetic induction coil ,temperature of both outside and inner surfaces decreased gradually .The decreasing trend of outside surface temperature became gentler and gentler ,while the decreasing trend of inner surface temperature became sharper and sharper .

Low-carbon Al-killed steel was selected and finite element method (FEM) was used to investigate the influence of phase transformation on strip temperature distribution and buckling in the heating and slow cooling sections of the continuous annealing furnace. The results show that in the heating section, phase transformation can inhibit the increase of transverse compressive stress caused by thermal stress and reduce temperature and transverse temperature difference of strip effectively, and thus it is helpful to prevent the strip buckling. Inhibition of phase transformation on strip buckling firstly increases and then decreases when annealed at 760?820 ℃. In the slow cooling section, phase transformation weakens the decrease of transverse compressive stress caused by thermal stress and reduces temperature of strip, which promotes the probability of strip buckling. Strip buckling is more likely to occur at higher annealing temperature.

介绍了激光拼焊板与连续变截面板技术、内高压成形技术、热成形技术和冷弯成形技术等多种先进的汽车板成形及深加工技术,总结了汽车板及其深加工技术的发展趋势及特点.同时指出:多种成形技术之间,多种材料之间的融合发展将成为今后汽车板及其应用技术重要的发展方向;钢铁生产企业需要更多地关注深加工技术发展,并不断延伸其产品产业链,不仅可以形成新的利润增长点,而且有利于对主业及深加工产业形成良性的循环,形成相互促进的局面.