Select

Effect of subcritical heat treatment on microstructure and properties of high chromium cast irons

Yuan Zhizhong, Liu Haiming, Ju Yulin, Chen Lu, Niu Zongran, Wang Zhiyuan, Cao Fuyang, Cheng Xiaonong

Heat Treatment of Metals 2024, 49 (10): 1-7. doi:10.13251/j.issn.0254-6051.2024.10.001

Abstract （244）

PDF （4765KB）（173）

Aiming at the problem of high energy consumption in conventional quenching and tempering process of high chromium cast irons, the subcritical heat treatment tests of three kinds of high chromium cast irons were carried out. Moreover, the effect of the process on the microstructure, hardness and surface wear resistance was studied. The results show that the microstructure of high chromium cast irons is primarily composed of retained austenite, M₇C₃ carbide, (Fe, Cr)₂₃C₆ carbide, Mo₂C carbide and pearlite when subjected to holding temperatures ranging from 500 ℃ to 650 ℃ for 1 h to 14 h. A peak value in hardness is observed for the three high chromium cast irons when holding at 550 ℃ to 600 ℃ for 6 h to 12 h, with the highest peak hardness being 57.4 HRC. The hardness is most significantly influenced by the Mo element. During the insulation process, the pearlite phase transformation of austenite is promoted by the precipitation of secondary carbides in high chromium cast irons. The effects of pearlite transformation strengthening and precipitation strengthening of secondary carbides gradually decrease with prolonged holding time. The eutectic high chromium cast iron with the highest carbon content exhibits the best wear resistance when holding at 600 ℃ for 8 h. It can be seen that the first step to improve the wear resistance of high chromium cast irons is to increase the amount of eutectic carbides, and then to add elements such as Mo to enhance the precipitation strengthening effect.

Reference | Related Articles | Metrics

Select

Effect of cryogenic treatment on microstructure and mechanical properties of H13 steel

Di Yingnan, Ma Dangshen, Zhou Jian, Chi Hongxiao, Gu Jinbo

Heat Treatment of Metals 2024, 49 (10): 38-42. doi:10.13251/j.issn.0254-6051.2024.10.006

Abstract （240）

PDF （3226KB）（67）

Microstructure evolution and mechanical properties of the H13 steel during cryogenic treatment for different time (0-4 h) were studied. The phases and microstructure were analyzed by XRD and SEM, and the mechanical properties were characterized by hardness, impact and tensile tests. The experimental results show that the cryogenic treatment can refine martensite laths, promote the transformation of retained austenite to martensite and the precipitation of banded carbide. The increase of C content in martensite results in increasing in lattice constant and in lattice distortion effect, and a shift to the left in the XRD diffraction peak. With the prolongation of cryogenic treatment time, the strength and hardness of the steel show an upward trend, while the toughness and plasticity gradually decrease. Under the condition of maintaining the same hardness, the plasticity of the H13 steel after cryogenic treatment is comparable to that of the normal heat treatment, and its strength and toughness are improved.

Reference | Related Articles | Metrics

Select

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 （235）

PDF （5140KB）（289）

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

Select

Effect of secondary forging deformation on microstructure and impact properties of Cr-Mo-V die steel after spheroidal annealing

Xia Yunfeng, Ma Danning, Yang Qiang, Zhou Zhongcheng, Wang Jiaoqi

Heat Treatment of Metals 2024, 49 (10): 99-104. doi:10.13251/j.issn.0254-6051.2024.10.016

Abstract （192）

PDF （3596KB）（37）

Effect of secondary forging deformation on microstructure, precipitation and impact properties of Cr-Mo-V die steel was studied by means of metallographic microscope, scanning electron microscope, high resolution transmission electron microscope and impact testing machine. The results show that compared with conventional upsetting and drawing deformation, the microstructure and network carbides of the die steel after spheroidizing annealing under secondary radial forging and secondary upsetting and drawing deformation processes are significantly optimized, the impact absorbed energy are improved by 12% and 58%, respectively, and the precipitated carbides increases in quantity and is dispersed.

Reference | Related Articles | Metrics

Select

Effect of austenitization temperature on microstructure and mechanical properties of 40CrMnSi2Mo steel under air cooling

Yu Linran, Liu Geng, Yang Zhuoyue, Su Jie, Ning Jing, Ding Yali

Heat Treatment of Metals 2024, 49 (12): 1-8. doi:10.13251/j.issn.0254-6051.2024.12.001

Abstract （179）

PDF （5846KB）（158）

Effect of austenitization temperature (875-975 ℃) on the microstructure and mechanical properties of the novel Cr-Mn-Si series high strength medium carbon low alloy 40CrMnSi2Mo steel under air cooling condition was studied by means of optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and laser scanning confocal microscope (LSCM). The results show that when austenitized at 875 ℃ and 900 ℃, the microstructure is dominated by martensite with a small amount of the undissolved precipitates (NbC). The prior austenite grains are fine and stable. The tensile strength is 1997 MPa and 2003 MPa, the elongation is 11.0% and 12.0%, and the fracture toughness is 70.3 MPa·m^1/2 and 73.6 MPa·m^1/2, respectively. When austenitized at 975 ℃, the solubility of NbC increases and the pinning effect decreases. The growth of austenite grain size decreases the thermal stability so that the coarse bainite/martensite multiphase is obtained under air cooling. The tensile strength is 1980 MPa, the elongation is 10.5%, and the fracture toughness is only 77.6 MPa·m^1/2. The effect of the austenite grain refinement on the strength and toughness of the 40CrMnSi2Mo steel is not obvious. The fine bainite/martensite multiphase can be obtained after austenitizing at 950 ℃. The mechanical properties achieve an excellent combination, with the tensile strength of 2040 MPa, the elongation of 12% and the fracture toughness of 86.6 MPa·m^1/2.

Reference | Related Articles | Metrics

Select

Effect of spheroidization annealing process on austenite grain size of 16MnCr5 steel for carburizing

Zheng Xiaowei, Lin Zaiyong, Zhang Jianfeng, Jin Tao

Heat Treatment of Metals 2023, 48 (5): 283-286. doi:10.13251/j.issn.0254-6051.2023.05.045

Abstract （167）

PDF （1777KB）（73）

In order to study the effect of spheroidizing annealing on austenite grain size of 16MnCr5 steel hot rolled wire rods during the process of modification, hot-rolled wire rod specimen and specimens isothermally spheroidizing annealed at 700, 720, 740, 760 and 780 ℃, respectively, for 5 h were subjected to water quenching at 940 ± 5 ℃ for 1 h. The austenite grain size of the specimens was measured and compared. The results show that the “double high” processes (heating temperature of 1200-1250 ℃, finishing rolling temperature of 950-980 ℃) and rapid cooling between 800-600 ℃ (air cooling, cooling rate ≥ 10 ℃/s) are used in the rolling process to ensure that aluminum and nitrogen atoms are in a solid solution state. During the heat treatment process before austenite grain detection, AlN is uniformly and finely precipitated, resulting in fine and uniform austenite grains in the 16MnCr5 steel. When spheroidizing annealed at 700 and 720 ℃, AlN particles are uniformly and finely precipitated. Although Ostwald aging and growth occur, the AlN particles are still smaller than the critical radius, and the austenite grains are still fine and uniform. With the further increase of spheroidizing annealing temperature, the second phase particles undergo Ostwald aging and growth. The second phase particles in local areas exceed the critical radius, and local austenite grains grow abnormally, resulting in mixed grains. In practical production, in order to obtain uniform and fine austenite grains, as well as good spheroidized microstructure and mechanical properties, 16MnCr5 steel is spheroidizing annealed at 720 ℃. Through the above controlled rolling process and spheroidizing annealing process, the austenitic grain size of 16MnCr5 steel can reach 7.5 grade to 7 grade, meeting the requirements of austenitic grain size ≥ 5 grade and without mixed grains.

Reference | Related Articles | Metrics

Select

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 （160）

PDF （1962KB）（62）

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

Select

Effect of solution treatment on microstructure and low temperature impact properties of 022Cr22Ni5Mo3N duplex stainless steel

Cui Liyun, Liu Qingtao, Luo Rui, Qian Xigen, Ding Hengnan, Sun Xi, Zhao Xiaotao, Liu Heng, Cheng Xiaonong

Heat Treatment of Metals 2024, 49 (10): 18-24. doi:10.13251/j.issn.0254-6051.2024.10.003

Abstract （155）

PDF （5070KB）（95）

Solution treatment for as-forged 022Cr22Ni5Mo3N duplex stainless steel was carried out, and the effects of solution temperature (1000-1100 ℃) and time (1 h and 2 h) on the microstructure and -46 ℃ low temperature impact properties were studied. The results show that with the increase of solution temperature, the austenite content of the 022Cr22Ni5Mo3N stainless steel decreases, the phase boundary of austenite tends to be smooth and the number of needle-type and island austenite in ferrite decreases gradually. The low temperature impact properties increase first and then decrease with the increase of solution temperature. When the solution temperature is 1050 ℃, the low temperature impact absorbed energy of the 022Cr22Ni5Mo3N stainless steel is higher, which is about 260 J. The solution treatment can change the austenite phase morphology and adjust the phase content. Serrated phase boundaries(below 1050 ℃) and lower austenite phase content(above 1050 ℃) promote the brittle fracture of dual-phase steels at low temperatures, which is the main reason for the reduction of low-temperature toughness.

Reference | Related Articles | Metrics

Select

Effect of annealing process on grain size and texture intensity of non-oriented silicon steel

Wang Haijun, Niu Yuhao, Qiao Jialong, Ling Haitao, Qiu Shengtao

Heat Treatment of Metals 2023, 48 (12): 44-55. doi:10.13251/j.issn.0254-6051.2023.12.007

Abstract （151）

PDF （3414KB）（48）

Annealing processes of non-oriented silicon steel are described, and the researches on the effects of annealing temperature, annealing time, heating rate and annealing atmosphere on grain size and texture intensity of non-oriented silicon steel in recent twenty years are reviewed. In addition, the differences of microstructure and texture evolution of the cold-rolled sheet before and after annealing are compared and analyzed. Finally, the evolution characteristics of grains and textures during annealing of the non-oriented silicon steel are summarized.

Reference | Related Articles | Metrics

Select

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 （145）

PDF （4261KB）（34）

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

Select

Effect of annealing process on structure and properties of a low cost 980 MPa cold-rolled dual-phase steel

Liu Pengfei, Guan Lin, Liu Jian, Chen Yu, Liu Hongliang

Heat Treatment of Metals 2024, 49 (3): 122-127. doi:10.13251/j.issn.0254-6051.2024.03.021

Abstract （140）

PDF （4034KB）（55）

By simulating the continuous annealing process of a cold rolled 980 MPa dual-phase steel by a Vatron Voestalpine thermal simulator, the effect of soaking temperature, slow cooling temperature, overaging temperature and the strip speed in continuous annealing on microstructure and mechanical properties of the dual-phase steel was studied by means of tensile testing machine, optical microscope and scanning electron microscope. The results show that with the increase of the soaking temperature in the range of 820, 840 and 860 ℃, the proportion of ferrite decreases and the yield strength increases. A certain amount of bainite appeares in the microstructure when the soaking temperature is increased to 860 ℃, which leads to the tensile strength reach the lowest value 1020 MPa. The slow cooling temperature can change the volume fraction of martensite and affect the mechanical properties of dual-phase steel. When the overaging temperature varies among 250, 270, 290, 310 and 330 ℃, with the overaging temperature increases, the degree of softening of the martensile increases, the tensile strength decreases and the total elongation of the tested steel increases. With the increase of overaging temperature above 310 ℃, the decomposition of martensite is promoted, and at the same time the precipitations of second phases are increased and the yield strength decreases first and then increases. Comprehensively considering the mechanical properties control of the cold rolled dual-phase steel under different annealing processes, the optimal annealing parameters are selected as soaking temperature of 840 ℃, slow cooling temperature of 680 ℃, overaging temperature of 250 ℃ and the strip speed of 120 m/min, under which the maximum value of the product of strength and elongation is 15.6 GPa·%.

Reference | Related Articles | Metrics

Select

Effect mechanism of intermediate annealing temperature on microstructure and texture of 3.5%Si non-oriented silicon steel during secondary cold rolling

Wei Hui, Lin Yuan, Wang Hongxia, Wang Shijia, Li Xu, Zhang Wenkang, Wang Yide

Heat Treatment of Metals 2024, 49 (3): 37-43. doi:10.13251/j.issn.0254-6051.2024.03.007

Abstract （139）

PDF （4653KB）（37）

Secondary cold rolling process was implemented for the trial production of high-grade non-oriented silicon steel, which had a thickness of 0.25 mm and a Si content of 3.5%. The evolution of microstructure and texture of the non-oriented silicon steel at different intermediate annealing temperatures (850, 950 and 1050 ℃) was studied by means of OM, EBSD, XRD and square coil magnetic properties testing. The results show that with the increase of intermediate annealing temperature, the average grain size of the finished annealed sheet increases first and then decreases, and the strength of the cube and Goss textures of the finished annealed sheet increases first and then decreases, the magnetic induction strength B₅₀₀₀ of the finished annealed sheet increases first and then decreases, while the iron loss value P_1.0/400 decreases first and then increases. When the intermediate annealing temperature is 950 ℃, due to the larger average grain size and the best grain uniformity, the number of shear bands after two-stage cold rolling is the highest, providing a large number of nucleation sites for cube and Goss textures during the annealing process of the finished sheet, resulting in texture strengths of 13.56 and 5.03, respectively, resulting in the highest magnetic induction intensity, with B₅₀₀₀ of 1.691 T, and the iron loss is the lowest, with P_1.0/400 of 13.36 W/kg.

Reference | Related Articles | Metrics

Select

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 （135）

PDF （5916KB）（127）

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

Select

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 （135）

PDF （7786KB）（126）

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

Select

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 （123）

PDF （2579KB）（38）

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

Select

Hot rolled and normalized microstructure and texture of high strength non-oriented electrical steel at different finish rolling temperatures

Qiao Pengfei, Wu Zhongwang, Zhang Huimin, Jin Zili, Ren Huiping, Guo Huan

Heat Treatment of Metals 2024, 49 (5): 153-157. doi:10.13251/j.issn.0254-6051.2024.05.025

Abstract （121）

PDF （2062KB）（26）

Microstructure and texture of the high strength non-oriented electrical steel hot rolled at different finish rolling temperatures and normalized were studied by means of optical microscope (OM) and electron backscattering diffraction analysis (EBSD). The results show that the higher the finish rolling temperature of the hot rolled plate, the stronger the tendency of grain aggregation and growth, the stronger the dynamic recrystallization ability, the coarser the grains. When the finish rolling temperature is low, the deformation stored energy generated during hot rolling process is released during normalization process, and the recrystallization ability is stronger. Along the thickness direction, the surface texture of the hot rolled plate is mainly Goss texture ({110}<001>), and the center layer is mainly rotating cubic texture ({001}<110>). The texture of the normalized plate corresponds to that of the hot rolled plate, and with the increase of finish rolling temperature, the proportion of favorable texture raises.

Reference | Related Articles | Metrics

Select

Effect of laser power on microstructure evolution and mechanical properties of Ni60/WC coatings

Han Jitai

Heat Treatment of Metals 2023, 48 (12): 65-73. doi:10.13251/j.issn.0254-6051.2023.12.010

Abstract （118）

PDF （6808KB）（58）

Ni60/WC composite coatings were successfully prepared on Cr12MoV substrate by laser cladding technology. The effect of laser power on the mechanical properties of the composite coatings was studied. The microstructure, microhardness and wear resistance of the composite coatings were characterized by SEM, Vickers hardness tester, reciprocating friction and wear tester, respectively. The wear mechanism of the composite coatings was further revealed. The results show that lower laser energy input cannot satisfy the melting requirements of WC particles, which weakens the forming quality of composite coatings. The WC particles in composite powders can be fully melted to generate Ni₂W₄C, M₇C₃, M₆C type carbides under relatively higher laser power conditions. With the increase of laser power, the wear resistance of the Ni60/WC composite coatings first increases and then decreases, where the WC particles produce fine grain strengthening and induce the in-situ carbide hard phase to improve the mechanical properties of the composites. In a certain range, with the increase of laser power, the average microhardness of the composite coating increases, reaching 852.35 HV0.2 at most, and the average friction coefficient and wear rate decrease, reaching 0.117 45 and 0.5849×10^-8 mm²/N at least, respectively. The furrow and flake peeling on the wear scar surface are reduced, and the wear resistance of the coating is significantly improved. However, with the increase of laser power, the mechanical properties of the composite coating are reduced due to the large internal residual thermal stress and grain coarsening.

Reference | Related Articles | Metrics

Select

Effect of decarburizing annealing process on texture and magnetic properties of thin-gauge oriented silicon steel

Wang Yitong, Liu Xuming, Guo Han, Geng Zhiyu, Xue Feng

Heat Treatment of Metals 2024, 49 (6): 17-22. doi:10.13251/j.issn.0254-6051.2024.06.003

Abstract （117）

PDF （8248KB）（38）

Microstructure,texture and magnetic properties of thin-gauge oriented silicon steel after annealing at different temperatures (820, 840, 860 ℃) and time (120, 150 s) were compared by means of EBSD and XRD. The results show that increasing the decarburization annealing temperature and decreasing the decarburization annealing time can reduce the grain size, increase the proportion of favorable texture and recrystallization ratio of the oriented steel, which provide the basis for the abnormal growth of Goss grains in the process of secondary recrystallization, so as to improve the magnetic properties of the oriented silicon steel. When the decarburization annealing temperature is 860 ℃ and the annealing time is 120 s, the oriented silicon steel specimen obtains the best magnetic properties, with the magnetic induction intensity J₈₀₀ of 1.807 T and the core loss P_1.7 of 1.07 W·kg^-1.

Reference | Related Articles | Metrics

Select

Effect of aging process on microstructure and mechanical properties of 2219 aluminum alloy

Wang Huimin, Li Yanguang, Ma Bingxin

Heat Treatment of Metals 2023, 48 (10): 123-128. doi:10.13251/j.issn.0254-6051.2023.10.017

Abstract （116）

PDF （3318KB）（35）

Effect of aging process on microstructure and mechanical properties of 2219 aluminum alloy was investigated by means of tensile test, transmission electron microscope (TEM) and scanning electron microscope (SEM). The results show that the aging hardening response of the 2219 aluminum alloy is very slow when the alloy is aged at 120 ℃, even aged for a long time, the alloy is still under aging. When the 2219 aluminum alloy is aged at 150, 165 and 175 ℃, it shows a dual-peak aging curve, owing to the overlap of precipitation of GP zones and formation of θ″ phase, and the aging process is divided into three stages as under-aging, peak-aging and over-aging. With the increase of aging temperature, the aging hardening response of the 2219 aluminum alloy becomes faster, the elongation and peak-aging time are reduced, so in comprehensive consideration of the strength and elongation of the alloy, the favorable aging process is at 165 ℃×24 h. After peak aging (165 ℃×24 h), the ultimate tensile strength, yield strength and elongation of the aluminum alloy are 412.2 MPa, 310.8 MPa and 7.9%, respectively.

Reference | Related Articles | Metrics

Select

Effect of intercritical annealing on microstructure and properties of ferrite/bainite dual-phase steel

Shi Lei, Tian Pengyong, Shi Ying, Bai Xue, Yang Fang

Heat Treatment of Metals 2024, 49 (5): 158-161. doi:10.13251/j.issn.0254-6051.2024.05.026

Abstract （112）

PDF （1906KB）（19）

Effect of intercritical annealing process on microstructure and mechanical properties of ferrite/bainite dual-phase steel was studied by means of thermal simulation test machine, microhardness tester, electronic universal tensile testing machine, optical microscope and scanning electron microscope. The results show that under traditional intercritical annealing process, the microstructure is composed of ferrite, bainite and a small amount of martensite, and showing banded structures. The quenching+intercritical annealing process can refine the microstructure, obtain lath ferrite/bainite dual-phase structures, and inhibit the formation of martensite. Moreover, different processes obtain similar volume fractions of ferrite. Compared with the traditional intercritical annealing process, the quenching+intercritical annealing process can significantly reduce yield ratio and improve elongation of the tested steel.

Reference | Related Articles | Metrics

Content of PROCESS RESEARCH in our journal