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  Heat treatment for toughening technology of cold working die steel SKD11 Yuan Zhizhong, Wang Mengfei, Zhang Bocheng, Duan Xubin, Li Biaomin, Yang Haifeng, Luo Rui, Cheng Xiaonong Heat Treatment of Metals    2023, 48 (9): 1-7.   doi:10.13251/j.issn.0254-6051.2023.09.001 Abstract （142）      PDF （5140KB）（178）       Knowledge map    SKD11 steel plate after hot rolling and spheroidizing annealing was used. Two kinds of complex phase heat treatment processes, A-Q-A (Austempering-Quenching-Austempering) and Q-T-A (Quenching-Tempering-Austempering), as well asconventional Q-T(Quenching-Tempering) heat treatment process were carried out.The effect of heat treatment process on the microstructure, hardness and impact absorbed energy was studied. The results show that the microstructure of the specimens after A-Q-A and Q-T-A is the combination of lower bainite (LB) and martensite (M). The content of retained austenite is 13.2% and 18.6% for A-Q-A and Q-T-A, respectively. After A-Q-A, Q-T-A and conventional heat treatment Q-T, the hardness of the specimens is 58.5, 58.6 and 60.5 HRC and the impact absorbed energy is 31.3, 27.6 and 15 J, respectively. The excellent combination of strength and toughness of the SKD11 steel plate is realized by the duplex-phase heat treatments, which does a beneficial exploration in improving the toughness of the cold working die steel. Reference | Related Articles | Metrics

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  Austenite grain distribution law in 34CrNi3MoV steel Zheng Bing, Xu Dong, Wang Yiqun, Wang Xuexi, Zhao Hongyang, Ju Dongying Heat Treatment of Metals    2023, 48 (7): 1-7.   doi:10.13251/j.issn.0254-6051.2023.07.001 Abstract （102）      PDF （2733KB）（118）       Knowledge map    Effects of different holding temperature and holding time on austenite grain growth of 34CrNi3MoV steel were studied. The effects of holding temperature and holding time on average grain size, major axis and minor axis were analyzed by means of metallography. The results show that in the Gaussian distribution equation, the standard deviation and expectation increase with the increase of holding temperature and holding time. The size of the major axis and minor axis of grains is closely related to the average size, and the ratio has a simple linear relationship. During the grain growth, the ratio of the major axis to the minor axis basically remains unchanged. The distribution probability expressions of average grain size, major axis size and minor axis size are obtained by regression. At the same time,a new way of thinking and possible explanation for the heredity in materials science in terms of mathematical laws is provided. Reference | Related Articles | Metrics

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  Carbide evolution law of high chromium and high vanadium powder metallurgy tool steel M390 during austenitizing Deng Jinqiang, Zhang Qinyi, Chen Jun, Wu Dong, Liu Wei, Zhou Hongfeng Heat Treatment of Metals    2023, 48 (11): 1-7.   doi:10.13251/j.issn.0254-6051.2023.11.001 Abstract （93）      PDF （4216KB）（101）       Knowledge map    Evolution of carbides in the M390 steel during different austenitizing processes was studied using analysis methods such as SEM-EDS, TEM, and Image-Pro Plus. The results show that under the austenitizing conditions of heating at 1075-1150 ℃ and holding for 15-120 min, the volume fraction and average size of carbides in the M390 steel show a decreasing trend as the quenching temperature increases. At the same quenching temperature, with the prolongation of holding time, the amount of carbides decreases as a whole, the average size of carbides decreases first and then increases, while the amount of small carbides and hardness increase first and then decrease. The types of undissolved carbides in high temperature oil quenched steel are mainly M7C3 and M8C7. During austenitizing, the change of carbides in the M390 steel is mainly the dissolution, growth and dissolution of M7C3. Reference | Related Articles | Metrics

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  Influence of quenching process on microstructure and wear resistance of GCr4Mo4V steel Cui Yi, Cui Jihong, Wang Yan, Zhang Yunfei, Yu Feng, Zhao Yingli, Cao Wenquan Heat Treatment of Metals    2023, 48 (9): 23-29.   doi:10.13251/j.issn.0254-6051.2023.09.004 Abstract （89）      PDF （7786KB）（97）       Knowledge map    Annealed GCr4Mo4V steel prepared by the process of “VIM+ESR” was oil quenched at 1090, 1120 and 1150 ℃ for 30, 60 and 120 min respectively, and then tempered three times continuously. The dry wear test was carried out on UMT TriboLab wear tester, and the evolution of its microstructure, surface hardness, wear scratch morphology and wear rate were analyzed, and the influence of quenching process on the microstructure and dry wear characteristics of the GCr4Mo4V steel were investigated. The results show that the quenching temperature of 1150 ℃ is the critical temperature for the rapid growth of grains. The increase of quenching temperature promotes the dissolution of large particle carbides. The prolongation of holding time is more conducive to the dispersion distribution of carbides after tempering. The quenching temperature has a greater effect on the refinement of large particle carbides than the holding time. The refinement and dispersion of grain structure and carbides have a positive effect on the improvement of wear resistance of the GCr4Mo4V steel. Reference | Related Articles | Metrics

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  Effect of quenching process on hardened depth and mechanical properties of 42CrMo steel cutter hub Jiang Ying, Du Shuiming, Huang Qiaomei, Shen Zida, You Fei Heat Treatment of Metals    2023, 48 (9): 88-91.   doi:10.13251/j.issn.0254-6051.2023.09.014 Abstract （88）      PDF （1962KB）（40）       Knowledge map    42CrMo steel cutter cub was quenched by using a multi-purpose furnace at different quenching temperatures, different quenching media and carbon potentials. The influence of various factors on mechanical properties and depth of hardened layer of the cutter cub was studied through the inspection of mechanical properties, microstructure and hardness. The results show that with the increase of quenching medium cooling rate, the tensile strength of the cutter cub quenched at 850-890 ℃ shows a trend of overall increase. When the quenching temperature is 850 ℃, the tensile properties of the cutter cub is the best when the quenching medium D is used, and the depth of quenched layer reaches 6.0 mm. When the quenching temperature is 870 ℃, after using C medium, the depth of quenched layer meets the customer's requirements. When the carbon potential is 0.6%, with the increase of quenching temperature, the depth of the quenched layer first increases and then decreases, the tensile strength decreases, and the yield strength and elongation increase. Reference | Related Articles | Metrics

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  Effect of microstructure homogenization on mechanical properties of Cr-Ni-Mo steel Shi Changxin, Gu Guochao, Cui Shugang, Xu Wenhua, Xiao Guiyong, Lü Yupeng Heat Treatment of Metals    2023, 48 (12): 1-6.   doi:10.13251/j.issn.0254-6051.2023.12.001 Abstract （86）      PDF （5916KB）（96）       Knowledge map    Homogenization treatment of AISI 4330 steel with banding defects was carried out through a step-by-step cyclic quenching and tempering heat treatment processes. The microstructure evolution and its effect on mechanical properties was studied during homogenization process. The results show that the original specimen with banded defects consists of ferrite and pearlite, with a banded structure level of 3. The element segregation of C, Cr, and Mo is significantly revealed by means of electron probe micro-analysis (EPMA). After undergoing multiple high-temperature quenching+quenching and tempering cycles, the microstructure transforms into a homogeneous structure consisting of ferrite, carbides containing Cr, and tempered sorbite. The element segregation is improved to a certain extent. Although the diffusion of C element is evident, segregation of Cr and Mo elements still exists. The step-by-step cyclic quenching process leads to lots of phase transformation, resulting in the refinement of microstructure of the steel. Furthermore, the mechanical properties of the steel are enhanced, resulting in tensile strength exceeding 1200 MPa, hardness of about 350 HBW, and impact absorbed energy at -40 ℃ of about 70 J. The refinement of microstructure contributes to the improvement in both strength and toughness of the specimen. Additionally, the large amount of precipitated carbonitride plays a beneficial role in increasing the strength of the steel. The enhanced strength and toughness characteristics fulfill the requirements of fracturing pump products and their service life. Reference | Related Articles | Metrics

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  Induction quenching process and distortion control of abnormity section at end of guide frame of rolling mill Wang Jingwei, Fan Meixiang, Lin Yichou, Shi Ruxing, Xi Zhiyong, Liu Zhigang Heat Treatment of Metals    2023, 48 (9): 122-125.   doi:10.13251/j.issn.0254-6051.2023.09.021 Abstract （80）      PDF （1291KB）（36）       Knowledge map    Heat treatment process and distortion control of induction quenching at the end of the rolling mill guide frame were studied, for which the corresponding end forgings were specially made and the inductor heating and cooling tests were carried out. At the same time, the relevant process tests were carried out. The hardness, distortion, cracking and other risks of the special-shaped section of the end of the guide frame were comprehensively evaluated. Based on the process test results of the end, an induction quenching process for the end of the guide frame was developed with the heating frequency of 1.7-4 kHz, the walking speed of 150 mm/min, and the power of 90×(14%-24%) kW. The magnetic displacement was designed for the inductor, and the continuous heating and continuous cooling induction quenching was adopted. The results show that based on end profiled structure designed by copying inductors by the process test, 40° guide end profiled induction quenching heat treatment can be realized. By setting the magnetic displacement area reasonably on the inductor, the sharp angle effect at the end of the noncircular section is effectively avoided, and is conducive to the uniformity of induction heating temperature. The C35E steel end after induction quenching hardness can reach 55-60 HRC. Through reverse distortion operation, the bending distortion of the end of the guide frame with a total length of 2120 mm can be controlled within 1 mm. Reference | Related Articles | Metrics

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  Heat treatment technologies for toughening of cold working die steel DC53 Yuan Zhizhong, Chen Lu, Zhang Bocheng, Wang Mengfei, Liu Haiming, Niu Zongran, Wang Zhiyuan, Cheng Xiaonong Heat Treatment of Metals    2023, 48 (10): 15-22.   doi:10.13251/j.issn.0254-6051.2023.10.002 Abstract （79）      PDF （6461KB）（30）       Knowledge map    Duplex phase heat treatments of austempering-quenching-austempering (A-Q-A) and austempering-quenching-tempering (A-Q-T) were processed to improve the toughness of cold working die steel DC53. The influence of heat treatments on microstructure and mechanical properties of the DC53 steel was analyzed and compared with conventional heat treatment of quenching-high temperature tempering (Q-T). The results show that lower bainite/martensite (LB/M) multiphase structures with retained austenite (AR) content of 21.7% and 16.5% is resulted from the A-Q-A and the A-Q-T specimens,respectively. The hardness of the A-Q-A and the A-Q-T specimens is 59.6 HRC and 59.9 HRC, respectively, slightly lower than that of Q-T, i.e. 62.3 HRC. However, the impact absorbed energy of these two processes are 84.9 J and 87.3 J, respectively, much higher than that of Q-T, i.e. 35.6 J. It is due to the fine grain strengthening of the duplex phase microstructure,deformation strengthening and the content increase in AR. Therefore, excellent coordination of strength and toughness can be achieved by LB/M duplex phase heat treatment, which enable the DC53 steel to be used in service environments with impact. Reference | Related Articles | Metrics

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  Effect of long-term aging on microstructure and properties of nickel-based superalloy Cai Chenyang, Cao Tieshan, Wang Wei, Chi Qingxin, Cheng Congqian, Zhao Jie Heat Treatment of Metals    2024, 49 (1): 9-15.   doi:10.13251/j.issn.0254-6051.2024.01.002 Abstract （74）      PDF （3643KB）（41）       Knowledge map    Microstructure of nickel-based superalloy with different aging time was observed to explore the evolution law of microstructure and properties in the process of high temperature aging. By using OM and SEM to observe and analyze the microstructure of the alloy before and after aging, a method for quantitative analysis of microstructure evolution was proposed, and the hardness of the alloy before and after aging was tested and analyzed. The results show that after aging at 900 ℃ for 20 h without loading, the γ′ phase is cuboidal and the size does not change obviously. When aging for 100 h, the γ′ phase changes from cube to circle. After aging for 500 h, the shape of γ′ phase becomes more irregular. Some γ′ phases are connected with neighboring γ′, showing a long strip shape, but some of them remain cubic shape. When aging for 2000 h, γ′ phase is coarsened obviously and cubed degree is decreased obviously. With the aging time, the size of γ′ phase grows gradually, and the hardness of the alloy shows a decreasing trend. Reference | Related Articles | Metrics

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  Crack initiation and propagation behavior in tensile deformation of high-strength titanium alloy with lamellar microstructure Huang Xiaowen, Liu Leliang, Liu Jixiong, Wang Xiaoxiang, Sun Qiaoyan Heat Treatment of Metals    2023, 48 (10): 78-86.   doi:10.13251/j.issn.0254-6051.2023.10.011 Abstract （72）      PDF （5886KB）（33）       Knowledge map    Crack initiation and propagation mechanism in tensile deformation of Ti1300 alloy with lamellar microstructure after solution and aging treatment was investigated in detail, and the influence of grain boundary with Widmanstätten α phase (GBWα) on crack initiation and propagation was revealed. The results show that, the tensile fracture exhibits a mixed morphology of transgranular dimples and intergranular fracture facets, while the statistical analysis indicates a reduction in the number of intergranular fracture facets is related to an increase in the elongation of the alloy. By counting the locations of secondary crack initiation near the fracture, it is found that about 77% of secondary cracks near the fracture surface initiate predominantly at β grain boundaries, while about 23% of secondary cracks are initiated within β grains. By proposing a crack initiation strain parameter to assess the corresponding strain magnitudes for crack initiation, it is found that the strain parameter for cracks initiated at grain boundaries is lower than that for cracks initiated within β grains, which indicating a lower strain requirement for crack initiation at grain boundaries. As for cracks initiated at grain boundaries, 88% of them initiate at the grain boundaries without GBWα, while only 12% at those with GBWα, which indicating that the GBWα can inhibit the crack initiation. The crack propagation path in the fracture process is a mixture of extending through the grains and along the grain boundaries, and the GBWα can deflect the crack path. Reference | Related Articles | Metrics

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  Effect of Ni content on microstructure and mechanical properties of 40CrNi3MoV steel strengthened by NiAl-Cu Liang Enpu, Xu Le, Yang Yong, Wang Maoqiu Heat Treatment of Metals    2023, 48 (8): 1-7.   doi:10.13251/j.issn.0254-6051.2023.08.001 Abstract （72）      PDF （5523KB）（76）       Knowledge map    For 40CrNi3MoV steel strengthened by NiAl-Cu precipitation, the effect of different Ni content on microstructure and mechanical properties of the tested steel tempered at 450-650 ℃ was studied. The microstructure of the tested steel was characterized by OM, the precipitates in the the tested steel were characterized by means of TEM and EDS, and the mechanical properties of the tested steel were measured by room temperature tensile and low temperature impact tests. The results show that the Ni content has no obvious effect on the microstructure of the tested steel. The increase of Ni content (3.0%-4.0%) promotes the precipitation of Cu-rich phase and NiAl phase in the tested steel, and increases the amount of nano particles. With the increase of Ni content, the tensile strength and yield strength of the tested steel tempered at 500 ℃ are increased by 200 MPa and 100 MPa, respectively. Reference | Related Articles | Metrics

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  Hot deformation behavior and microstructure evolution of a novel Co-Ni-based superalloy Fu Zhiqiang, He Guoai, Wu Yunjie, He Cunxiao Heat Treatment of Metals    2024, 49 (2): 1-7.   doi:10.13251/j.issn.0254-6051.2024.02.001 Abstract （70）      PDF （7060KB）（107）       Knowledge map    Gleeble-3800 thermal simulation testing machine was used to perform hot compression tests on a novel Co-Ni-based superalloy to study its hot deformation behavior and microstructure evolution at deformation temperature of 950-1100 ℃, strain rate of 0.01-10 s-1 and true strain of 0.693. The results show that the flow stress of the alloy decreases with the increase of deformation temperature or the decrease of strain rate. The average grain size of the alloy increases with the increase of deformation temperature and the dynamic recrystallization grains can be refined by reducing the deformation temperature and increasing the strain rate. The EBSD and TEM analysis results indicate that the discontinuous dynamic recrystallization (DDRX) is the main dynamic recrystallization (DRX) mechanism and the twin nucleation is the auxiliary nucleation mechanism during the hot deformation of the alloy. Reference | Related Articles | Metrics

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  Effect of final rolling temperature on phase transformation behavior and residual stress of NM400 steel Chen Hao, Ding Wenhong, Fang Yu, Lu Xiaoxuan, Zhou Yingtao, Chen Hao Heat Treatment of Metals    2023, 48 (9): 14-22.   doi:10.13251/j.issn.0254-6051.2023.09.003 Abstract （69）      PDF （5685KB）（46）       Knowledge map    In order to study the difference of shape defects of NM400 steel at different finishing rolling temperatures, the expansion test under compressive stress load was carried out by means of Gleeble-3500 thermal simulation testing machine. The effect of finishing rolling temperature on the phase transformation kinetics and phase transformation plasticity of the NM400 steel was studied, and the ABAQUS finite element model was established by using the modified phase transformation kinetics and phase transformation plasticity parameters. The residual stress of the NM400 steel was tested by crack flexibility method, and the accuracy of the finite element model was verified by comparing the measured and simulated results. At the same time, EBSD was used to characterize and analyze the microstructure of specimens with different finishing rolling temperatures. The results show that the formation of residual stress in the continuous cooling process is divided into three stages, including the dominant stage of temperature stress, the dominant stage of surface phase transformation and the dominant stage of core phase transformation. When the final rolling temperature is 860 ℃, the phase transformation rate is the largest, resulting in the surface phase transformation volume is 17 % larger than that at 820 ℃, so that the tensile stress level at the beginning of phase transformation becomes larger, and the residual stress after rolling is also the largest, resulting in plate shape problems during production and processing. The finishing rolling temperature has little effect on the microstructure and transformation plasticity parameter K after rolling, which is not the decisive factor causing the difference of residual stress after rolling. Reference | Related Articles | Metrics

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  Mechanism of α lamellae spheroidization and strengthening plasticization of TC21 titanium alloy after post forging heat treatment Tao Cheng, Cui Xia, Ouyang Delai, Lan Xixin, Wan Xingcai Heat Treatment of Metals    2023, 48 (8): 138-143.   doi:10.13251/j.issn.0254-6051.2023.08.022 Abstract （69）      PDF （4261KB）（21）       Knowledge map    TC21 titanium alloy was subjected to spheroidization heat treatment after multi-directional forging under optimal parameters(920 ℃-0.92 single pass true strain-3 cycles-water cooling), and the tensile properties of the specimens before and after forging and after spheroidization heat treatment were tested. The evolution law of α lamellae spheroidization (equiaxation) under different heat treatment parameters (temperature of 830-920 ℃, holding time of 1-4 h) of the alloy was studied and the strengthening plasticization mechanism of the alloy was revealed. The results show that after optimal multi-directional forging, the preferred subsequent spheroidizing heat treatment parameters for the TC21 titanium alloy are 890 ℃-2 h-air cooling, which can promote α lamellae spheroidization, and make that the yield strength and elongation of the TC21 titanium alloy are significantly improved, reaching 894.0 MPa and 13.2%, respectively. The strengthening plasticization mechanism of the TC21 titanium alloy after spheroidization heat treatment is mainly fine grain strengthening caused by α phase grain refinement and dislocation strengthening induced by needle-like secondary α phase in β phase. Reference | Related Articles | Metrics

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  Spheroidizing process of SWRCH35K cold heading steel Tian Wei, Wang Xing, Zhi Xubo, Chen Zongle Heat Treatment of Metals    2023, 48 (8): 190-193.   doi:10.13251/j.issn.0254-6051.2023.08.031 Abstract （67）      PDF （2579KB）（29）       Knowledge map    In order to improve the spheroidized structure and cold heading quality of SWRCH35K steel, and to realize on-line annealing control after hot rolling, the phase transformation point of the SWRCH35K cold heading steel was obtained by thermodynamic simulation, and the hot rolled steel was heat treated by isothermal spheroidizing, high temperature tempering and high temperature tempering+isothermal spheroidizing. The results show that there are some long lamellar carbides in the granular pearlite formed after isothermal spheroidizing, and the uneven distribution of carbides is due to the re-precipitation of proeutectoid ferrite heated at the high temperature of the two-phase region, and lamellar pearlite is formed at 790 ℃; the carbides in the lamellar pearlite can become granular form by high temperature tempering, but the distribution of granular carbides is not uniform. The granular pearlite obtained by high temperature tempering and isothermal spheroidizing has good microstructure, uniform distribution of carbides and no obvious long lamellar carbides, so its best heat treatment system is 685 ℃×1.5 h, air cooling+740 ℃×0.5 h, furnace cooling to 685 ℃×3 h, then air cooling. Reference | Related Articles | Metrics

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  Discussions of physical stability and increasing routes of sintered rare-earth NdFeB magnets Wu Yucheng, Liu Jiaqin Heat Treatment of Metals    2023, 48 (10): 8-14.   doi:10.13251/j.issn.0254-6051.2023.10.001 Abstract （65）      PDF （1681KB）（60）       Knowledge map    Sintered rare-earth NdFeB is an important functional material, which is broadly applied in automobile, medical equipment and aerospace fields etc. The preparation, application and control of physical stability were reviewed through involving in optimizing the composition and tailoring grain boundary structure, exploring the effects on micro mechanism of the stability through powder metallurgy route. The influence of chemical composition and microstructure on the stability of the magnetic fields and temperature was concluded by analysing the stability of sintered Nd-Fe-B magnets under different conditions. Reference | Related Articles | Metrics

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  Influence of DQ-T process on microstructure and properties of 1000 MPa high strength steel Wang Yi, Han Jie, Liu Chao, Deng Lingrui, Li Hui, Xu Rongchang Heat Treatment of Metals    2023, 48 (9): 30-34.   doi:10.13251/j.issn.0254-6051.2023.09.005 Abstract （63）      PDF （3197KB）（60）       Knowledge map    Effect of direct quenching+tempering process on the microstructure and mechanical properties of 1000 MPa grade high strength steel was studied. The microstructure was characterized by means of metallographic microscope and transmission electron microscope, and the Vickers hardness and tensile properties were tested. The results show that as the tempering temperature increases, the decreasing trend of microhardness and tensile strength is divided into three stages: slowly descending Ⅰσ stage (room temperature to 350 ℃), rapidly decreasing Ⅱσ stage (350-500 ℃) and basically stable Ⅲσ stage (above 500 ℃). There is a peak in yield strength after tempering at 250-400 ℃, and the yield strength ratio increases significantly. When the tempering temperature reaches above 500 ℃, the elongation can reach over 15%. After finishing rolling at 850 ℃ and tempering at 350-450 ℃ for 30-60 min, a good combination of strength and toughness can be obtained, which meets the performance indicators of the 1000 MPa grade high-strength steel. There are a lot of dislocation substructures in the martensite structure, in which the movable dislocation can alleviate the local stress concentration, reduce the possibility of microcrack formation, so that the material can obtain large uniform plastic deformation. Reference | Related Articles | Metrics

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  Effects of forced cooling and low temperature aging on microstructure and mechanical properties of FSW joint of 2198-T3/7A04-T6 dissimilar aluminum alloy Sun Bo, Nie Jiamin, Li Xiaodan, He Changshu Heat Treatment of Metals    2023, 48 (9): 8-13.   doi:10.13251/j.issn.0254-6051.2023.09.002 Abstract （62）      PDF （3133KB）（51）       Knowledge map    2198-T3/7A04-T6 dissimilar aluminum alloy was friction stir welded under air cooling and forced cooling respectively, and the joint was aged at low temperature after welding. The effects of forced cooling and low temperature aging on the microstructure characteristics and mechanical properties of the welded joint were studied. It's found that a low hardness zone appears in the heat affected zone of the 2198-T3 aluminum alloy side under both conditions, but the hardness value of the low hardness zone of the joint under forced cooling+low temperature aging conditions is significantly higher, reaching 94.5 HV0.1. The average yield strength, tensile strength and elongation of the joint are 312 MPa, 443 MPa, and 8.9%, respectively. The yield strength and tensile strength reach 97.5% and 96.9% of the base material strength, respectively. However, under air cooling and low temperature aging conditions, they are only 89.0% and 91.6% of the base material strength. The main reason for the better mechanical properties of joint under forced cooling and low-temperature aging conditions is that applying forced cooling during the welding can effectively suppress the dissolution and coarsening of θ′ and T1 phases in the low hardness zone of the joint, enabling it to achieve better aging strengthening effect in the subsequent low-temperature aging treatment. Reference | Related Articles | Metrics

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  Research progress on heat treatment of β titanium alloy Xiao Hao, Sun Yang, Fan Juanjuan, Wei Haitao, Yi Junying, Yao Liu Heat Treatment of Metals    2023, 48 (11): 258-265.   doi:10.13251/j.issn.0254-6051.2023.11.043 Abstract （60）      PDF （3348KB）（22）       Knowledge map    β titanium alloy is widely used in the fields of high performance and advanced engineering such as aerospace, marine, military and biomedical, but the current process application puts forward higher requirements for its properties. β titanium alloy can be strengthened by heat treatment. The heat treatment process of β titanium alloy in recent years was reviewed. Firstly, the main phase composition and phase transformation of β titanium alloy were systematically overviewed. Then, the effects of typical heat treatment process, plastic deformation mechanism and newly developed pre-deformation aging process on microstructure evolution and properties were described and analyzed. Finally, the development trend of heat treatment process of β titanium alloy was prospected. Reference | Related Articles | Metrics

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  Effect of primary recrystallization annealing temperature on microstructure and texture of low temperature Hi-B steel Liu Lei, Guo Feihu, Shi Pengzhao, Qiao Jialong, Qiu Shengtao Heat Treatment of Metals    2023, 48 (7): 8-14.   doi:10.13251/j.issn.0254-6051.2023.07.002 Abstract （59）      PDF （6017KB）（51）       Knowledge map    Effect of annealing temperature of primary recrystallization on the microstructure, texture and grain boundary characteristics of low-temperature Hi-B steel was studied by means of metallographic microscope, X-ray diffractometer and EBSD. The results show that the annealing temperature of the primary recrystallization directly affects the microstructure uniformity and the average grain size of the low-temperature Hi-B steel. With the increase of annealing temperature, the average grain size of the primary recrystallization structure increases from 15.2 μm to 26.7 μm, the primary recrystallization microstructure has the best uniformity after annealing at 820 ℃. The main texture types of primary recrystallization are: γ texture, α texture, {001}<120> texture and {114}<481> texture. When the annealing temperature rises to 880 ℃, the texture strength of {001}<120> increases obviously. With the increase of annealing temperature, the number of Goss grains decreases, area fraction of {114}<481> first decreases and then increases, while area fraction of {111}<112> begins to decrease after the annealing temperature rises to 840 ℃. When the annealing temperature is 800 ℃, the proportion of misorientation 20°-45° angle between {110}<001> grains and adjacent grains is the highest, which is 89.2%. The distribution of CSL grain boundaries around {110}<001> grains varies at different annealing temperatures. Reference | Related Articles | Metrics