Select

Effect of low temperature cold rolling and aging on microstructure and properties of Cu-Ni-Co-Si alloy

Xu Kaitai, Liu Qisheng, You Kaisi, Liu Zhaoyu, Zhang Junjia

Heat Treatment of Metals 2024, 49 (3): 1-6. doi:10.13251/j.issn.0254-6051.2024.03.001

Abstract （50）

PDF （4115KB）（70）

Effect of cold rolling and aging process on microstructure and properties of Cu-1.8Ni-0.9Co-0.641Si alloy sheet and strip was studied. The effects of liquid nitrogen cold rolling and room temperature cold rolling on the properties of the alloy sheet were compared, and the mechanism was analyzed by X-ray diffractometer (XRD), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results show that when the aging time is 60 min, the hardness of alloy sheet reaches the maximum after cold rolling at room temperature and low temperature, which are 285.53 HV0.3 at 450 ℃ and 307.2 HV0.3 at 400 ℃, respectively. It is also found that the conductivity of the alloy increases with the increase of aging temperature. After aging at 500 ℃, the conductivity of the low temperature cold rolled alloy is the highest, reaching 60.11%IACS. During the aging process, the dislocation density in the sheet decreases, and a large number of fine and uniform nanoscale (Ni,Co)₂Si ordered phases appear in the grains and on the grain boundaries. Compared with cold rolling at room temperature, the microstructure of the Cu-Ni-Co-Si alloy after low temperature cold rolling is finer and the dislocation density is higher.

Reference | Related Articles | Metrics

Select

Effect of tempering temperature on hydrogen embrittlement sensitivity of a low-alloy high-strength steel with Nb and V

Li Xiaoliang, Cheng Xiaoying, Wang Zhaofeng, Ren Yuwen, Zeng Fanyu

Heat Treatment of Metals 2024, 49 (3): 7-14. doi:10.13251/j.issn.0254-6051.2024.03.002

Abstract （22）

PDF （4661KB）（19）

In order to improve strength and simultaneously reduce hydrogen embrittlement sensitivity, a low-alloy high-strength steel with 0.11wt%Nb and 0.55wt%V was developed. The effect of three different tempering temperatures (560, 600, 640 ℃) on the microstructure, hydrogen diffusion behavior and hydrogen embrittlement sensitivity of the tested steel was characterized and studied by using optical microscope (OM), X-ray diffraction (XRD), transmission electron microscope (TEM), hydrogen permeation technique of double electrolytic cells and slow strain rate tensile test. The results show that with the increase of tempering temperature, the ferrite grain size increases while the dislocation density reduces, and the carbides precipitated become coarse, hence the tensile strength decreases and the elongation increases. Meanwhile, with the increase of tempering temperature, the density of hydrogen reversible traps reduces and the activation energy of hydrogen diffusion decreases, as well as the hydrogen diffusion coefficient increases, hence the hydrogen embrittlement sensitivity becomes lower.

Reference | Related Articles | Metrics

Select

Effect of solution temperature on microstructure and mechanical properties of K424 alloy

Zhao Xinlei, Yuan Xiaofei, Qiao Junwei

Heat Treatment of Metals 2024, 49 (3): 15-21. doi:10.13251/j.issn.0254-6051.2024.03.003

Abstract （24）

PDF （3523KB）（29）

Room temperature tensile test and the stress rupture test at 975 ℃/196 MPa were conducted in K424 alloy after solution treatment at different conditions (1200-1240 ℃×4 h, air cooling). The results show that the uniform fine γ' precipitates with high cubicity are reprecipitated in the K424 alloy after completely solution treatment at 1220, 1230 and 1240 ℃. The room temperature strength and plasticity of the K424 alloy after complete solution treatment at 1220-1240 ℃ for 4 h are slightly lower than that of incomplete solution treatment at 1200-1210 ℃ for 4 h, but the stress rupture life is higher. K424 alloy performs the highest stress rupture life (97.8 h) after treatment treatment at 1220 ℃ for 4 h, which is the optimal solution treatment process. The intragranular dislocation and grain boundary are nailed by irregular big γ' precipitates, which are responsible for the improvement of room temperature strength and plasticity of the K424 alloy after incomplete solution treatment. The higher mismatch, cubicity and γ' phase volume fraction, as well as the dissolved γ/γ' eutectics are responsible for the highest stress rupture life of the K424 alloy after complete solution treatment at 1220 ℃ for 4 h.

Reference | Related Articles | Metrics

Select

Effect of intercritical quenching on toughening and properties of low alloy wear-resistant steel

Hu Ang, Wu Run, Li Zhongbo, Wu Teng

Heat Treatment of Metals 2024, 49 (3): 22-27. doi:10.13251/j.issn.0254-6051.2024.03.004

Abstract （17）

PDF （4914KB）（16）

NM500 wear-resistant steel was toughed by intercritical quenching. The results show that after intercritical quenching at 790 ℃ and tempering at 170 ℃, the microstructure of the tested steel contains 7.3% volume fraction of ferrite, and the impact absorbed energy is increased from 40 J after complete quenching to 58 J, with the best wear resistance. Complete austenitization cooling to below Ac₃ followed by intercritical quenching reduces wear properties of the steel due to the distribution of ferrite, while impact absorbed energy does not change a lot. Intercritical quenching increases the carbon content of martensite, a small amount of needle-like ferrite in the structure can improve the toughness of the steel, and wear resistance is better than that of the complete quenched.

Reference | Related Articles | Metrics

Select

Effect of austempering temperature on microstructure and properties of 50CrVA steel

Zhang Yu, Yu Jinrui, Yu Xinhong, Feng Yisheng, Zhang Yunshan, Zhao Ertuan

Heat Treatment of Metals 2024, 49 (3): 28-32. doi:10.13251/j.issn.0254-6051.2024.03.005

Abstract （14）

PDF （3704KB）（14）

Traditional spring steel 50CrVA was taken as the research object, and the bainite transformation was realized by austempering at 350, 400, 450 ℃ in the furnace after water mist +air fast cooling. The effect of austempering temperature on microstructure and properties of the 50CrVA steel was studied by means of thermal simulation, SEM, XRD, tensile and impact tests. The results show that the bainite transformation rate first increases and then decreases with the increase of austempering temperature, and the transformation rate is the fastest at 400 ℃. The bainite transformation quantities at 350 ℃ and 400 ℃ are the same and higher than that at 450 ℃, this is due to the precipitation of carbides, which reduces the carbon content in the undercooled austenite, the bainite transformation is completed, thus obtaining full bainite microstructure. With the increase of austempering temperature, the bainite, cementite and M/A structure become coarser, resulting in a significant reduction in tensile and impact properties, and the fracture mode gradually changes from quasi-cleavage fracture to cleavage fracture.

Reference | Related Articles | Metrics

Select

Effect of hot rolling deformation on microstructure and properties of high aluminum 316L stainless steel

Zhang Lisheng, Wang Xiaogong

Heat Treatment of Metals 2024, 49 (3): 33-36. doi:10.13251/j.issn.0254-6051.2024.03.006

Abstract （15）

PDF （1700KB）（19）

Hot rolling with different deformations for high aluminum 316L stainless steel was carried out, and the effects of which on microstructure, tensile properties and fatigue properties of the 316L steel were studied using SEM and TEM characterization, as well as tensile and fatigue testing methods. The results show that the hot rolled high aluminum 316L stainless steel has austenitic and ferritic microstructure, while the strength and fatigue life of the tested steel can be improved by hot rolling deformation. With the increase of rolling deformation, the ferrite volume fraction and dislocation density in the tested steel microstructure increase gradually, the tensile strength and fatigue life increase obviously, while the elongation decreases. The tensile strength and fatigue life of the tested steel with 75% hot rolling deformation reach their maximum values, which are 937.6 MPa and 3.8 ×10⁷ times, respectively, while the elongation reachs the minimum value of 42.7%.

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 （15）

PDF （4653KB）（15）

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 tempering process on microstructure and properties of HT9 steel

Xie Pu, Zhao Jiqing, Yan Tingting

Heat Treatment of Metals 2024, 49 (3): 44-49. doi:10.13251/j.issn.0254-6051.2024.03.008

Abstract （16）

PDF （4738KB）（22）

Effect of tempering process on microstructure evolution and mechanical properties of HT9 steel was studied by SEM, TEM, phase analysis, tensile and impact tests. The results show that the tempering process can affect the mechanical properties of the tested steel by influencing the precipitates and dislocations. After tempering, the microstructure of the HT9 steel is lath martensite, and the precipitated phase is M₂₃C₆ carbide, and no other precipitated phase is observed. With the increase of tempering temperature, the matrix gradually recovers, the dislocation tangles are gradually normalized and thinned into dislocation networks, and forming subgrains. The M₂₃C₆ carbide undergoes Ostwald ripening, the precipitation strengthening and dislocation strengthening effects are weakened, the strength and hardness decrease, while the toughness increases. Tempered at 770 ℃ for 1-12 h, as the tempering time prolongs, the matrix gradually recovers and the M₂₃C₆ phase gradually ripens. The strength and hardness gradually decrease with a certain time dependence. According to the mechanical properties standards, the strength and toughness match well when the heat treatment system of the HT9 steel is quenching at 1040 ℃ for 1 h and tempering at 770 ℃ for 6 h.

Reference | Related Articles | Metrics

Select

Effect of normalizing process on microstructure and magnetic properties of grain-oriented silicon steel

You Wenhao, Chen Xia, Chen Bin

Heat Treatment of Metals 2024, 49 (3): 50-55. doi:10.13251/j.issn.0254-6051.2024.03.009

Abstract （11）

PDF （4773KB）（7）

Effect of normalizing temperature on the microstructure, texture and magnetic properties of 3.2wt%Si high magnetic induction orientation (Hi-B) silicon steel was studied by means of EBSD technique and single-chip measurement method. The results show that with the increase of normalizing temperature, the columnar grains of the normalized plate are completely recrystallized, and the texture types are similar to α texture, λ texture and Goss texture. After decarburizing annealing, the texture mainly consists of {114}<481>, γ texture and Goss texture, and the primary recrystallized grain size increases first and then decreases with the increase of normalizing temperature (maximum at 900 ℃ , up to 20.3 μm). After normalizing annealing at 850 ℃, the area fractions of {114}<481> texture and Goss texture, which are beneficial to magnetic properties, reach the highest (26.1% and 4.5%, respectively) in the primary recrystallized specimen. When the normalizing temperature is 850 ℃, the Hi-B steel can obtain the best magnetic properties, B₈=1.938 T, P_1.7/50= 0.828 W/kg.

Reference | Related Articles | Metrics

Select

Effect of laser surface treatment on microstructure and properties of martensitic stainless steel surfaced layer

Deng Dewei, Li Zhenhua, Chen Wenbo, Wang Hongsuo, Sun Lei

Heat Treatment of Metals 2024, 49 (3): 56-62. doi:10.13251/j.issn.0254-6051.2024.03.010

Abstract （12）

PDF （4520KB）（13）

In order to effectively repair the surface damage of FV520B steel and improve the corrosion resistance of the repaired surface, the method of surfacing followed by laser surface treatment was applied, i.e., surfacing was first performed by open-arc swing cladding method with martensitic-type flux-cored wires on the base material of the FV520B steel, and laser surface treatment was performed on the surfaced layer with two types of lasers (semiconductor and fibre optic lasers), respectively. The microstructure and hardness of the surfaced layer, the elemental distribution between the surfaced layer and the base material, as well as the microstructure, hardness, corrosion and depth of laser effects of the surfaced layer after laser surface treatment were investigated. The results show that the surfaced layer consists of martensite, δ-ferrite, retained austenite and carbide, and the hardness is about 480 HV0.3, which is about 33.33% higher than the base material, and the metallurgical bonding between the surfaced layer and the base material is well established. After laser surface treatment, the surfaced layer is categorised into the original surfaced zone, the heat affected zone and the remelted zone. In the heat affected zone, the hardness decreases, which is related to the tempering effect of the laser surface treatment, in the remelted zone, the hardness is comparable to the original surfaced zone. The results of the immersion experiments show that the laser surface treatment improves the corrosion resistance of the surfaced layer. As the scanning speed decreases, the depth of laser action increases, but the hardness does not change much. Compared with the fibre laser, the semiconductor laser has a greater depth of effect, but the surface hardness after both laser treatments is basically the same.

Reference | Related Articles | Metrics

Select

Effect of rare earth nitriding on QPQ salt bath composite treatment performance of 9Cr18Mo steel

Zhang Xin, Meng Zhengbing, Zhou Ying, Chen Yuanyu, Li Yuxiang

Heat Treatment of Metals 2024, 49 (3): 63-67. doi:10.13251/j.issn.0254-6051.2024.03.011

Abstract （7）

PDF （2346KB）（8）

In order to further improve the performance of 9Cr18Mo steel, the Quench-Polish-Quench (QPQ) rare earth nitriding agent was composed of self-made nitriding base salt as nitriding agent, potassium nitrate as oxidizing agent, lanthanum carbonate, yttrium carbonate and cerium carbonate as rare earth accelerator, and then the QPQ salt bath composite treatment was carried out for the 9Cr18Mo steel at 610 ℃. The effects of rare earth on the microstructure and properties of the 9Cr18Mo steel were studied by means of SEM, EDS, XRD, microhardness test, electrochemical performance test and wear resistance test. The results show that the surface of the QPQ salt bath composite treated specimen is mainly composed of oxide layer, nitriding layer and diffusion layer. The main component phases are Fe₄N, CrN, α_N, Fe_2-3N, Li₂Fe₃O₄ and Fe₃O₄. Compared with that without rare earth addition, the addition of rare earth on the QPQ salt bath composite treatment can increase the microhardness by 90 HV0.2 on average, and also improve the corrosion resistance and wear resistance.

Reference | Related Articles | Metrics

Select

Effect of heat treatment process on carbide precipitation in high Co and high V high-speed steel PM60

Yin Jinhua, Zhu Bailin, Hu Mulin, Peng Hui

Heat Treatment of Metals 2024, 49 (3): 68-76. doi:10.13251/j.issn.0254-6051.2024.03.012

Abstract （10）

PDF （5774KB）（10）

Compared with ordinary high speed steels, PM60 high-speed steel prepared by powder metallurgy contains a large amount of Co element, which can promote the precipitation of secondary carbides. The PM60 high-speed steel was quenched at 1120, 1150, 1180 and 1210 ℃, and oil cooling, and then tempered three times at 540, 560 and 580 ℃. After the heat treatment, the microstructure, precipitated phases, and hardness of the PM60 high speed steel after heat treatment were analyzed by metallographic microscope, scanning electron microscope, and Rockwell hardness tester. The types, morphology, composition, distribution, and precipitation behavior of the carbides in the samples before and after heat treatment were investigated by using JMatPro thermodynamic calculation software. The results show that the original precipitation phases are MC, M₆C, M₂₃C₆and M₇C₃ phases, after heat treatment, the precipitation phases are MC and M₆C phases. By energy spectrum analysis, two types of carbides are found: the dark V-rich carbides, and the bright W and Mo-rich carbides. In the quenching process, part of the carbides is dissolved, and in the tempering process, there is fine dispersive secondary carbides precipitated out. Under the condition of quenching at 1180 ℃+tempering at 540 ℃, the hardness of the tested steel is the highest.

Reference | Related Articles | Metrics

Select

Effect of solution nitriding temperature on microstructure and properties of 16Cr25N stainless steel

Guo Lulu, Ouyang Delai, Cui Xia, Zhu Enrui

Heat Treatment of Metals 2024, 49 (3): 77-82. doi:10.13251/j.issn.0254-6051.2024.03.013

Abstract （7）

PDF （3504KB）（10）

16Cr25N ferritic stainless steel was nitrided by a high-temperature solution nitriding process in a self-designed high-temperature and high vacuum nitriding furnace, and then the microstructure and properties of the nitrided layer were analyzed by means of X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, metallographic microscopy, microhardness tester, and oxygen nitrogen analyzer. The results show that an austenitic nitrided layer with a thickness of more than 1 mm is formed on the surface of the tested steel, with the maximum single-side thickness of the nitrided layer being more than 2 mm and the maximum nitrogen content reaching 1.502%, and the original ferrite microstructure transforms into austenite, which is equivalent to obtaining a high-nitrogen and nickel-free stainless steel. and its hardness after the nitriding treatment is greatly increased to 320 HV0.5. The activation energy of nitrogen diffusion during solid solution nitriding of the 16Cr25N stainless steel is calculated by the depth of the infiltration layer, which is 176 kJ/mol under the condition of nitrogen pressure of 0.3 MPa, insulation time of 24 h, and nitriding temperature of 1200 ℃. The nitrogen content model for high temperature solution nitrided layer of the 16Cr25N ferrite stainless steel is established by using the infiltration layer hardness and diffusion theory, which has certain guiding impact.

Reference | Related Articles | Metrics

Select

Process optimization of laser powder bed fusion for IN625 alloy based on densification and microstructure

Du Wenxiang, Cao Lice, Shen Falei, Pan Laitao, Wang Zelong, Sun Yedong, Fang Xiaoying

Heat Treatment of Metals 2024, 49 (3): 83-90. doi:10.13251/j.issn.0254-6051.2024.03.014

Abstract （8）

PDF （4566KB）（9）

A machine-learning approach based on gaussian process regression (GPR) was proposed to optimize the processing window of laser power (P) and scanning speed (v) in the IN625 alloy fabricated by laser powder bed fusion (LPBF) using the experimental data of relative density, crystallography orientation and shape aspect ratio of columnar grains. The effect of laser power-scanning speed combinations and laser energy density (ED) on the relative density and microstructure of the LPBF specimens was investigated as well. The results show that the applied laser ED≥55 J/mm³ is prerequisite for fully dense LPBF specimens with relative density ≥99%. The optimized L-PBF processing window for manufacturing fully dense IN625 alloy is pear-shaped, and the selectable scanning speed range can be wide in the case of high laser power. The LPBF specimens possess the columnar grains with the preferred orientation <001> parallel to build direction (BD). The preferred orientation intensity and the shape aspect ratio of the columnar grains tend to increase with the laser ED but marginally decrease after a high ED value. The leave-one-out cross validation reveals that the GPR model predicting the optimized LPBF process window based on relative density and microstructure features is reliable and can be readily applied to multi-objective optimization of laser additive manufacturing process in other metals and alloys.

Reference | Related Articles | Metrics

Select

Influence of annealing temperature on formability and recrystallization texture of an extra-deep drawing steel for enameling

Liu Zaiwang, Guo Min, Teng Huaxiang, Yang Libin, Liang Xuan, Liu Guanghui, Liu Shunming

Heat Treatment of Metals 2024, 49 (3): 91-97. doi:10.13251/j.issn.0254-6051.2024.03.015

Abstract （10）

PDF （2677KB）（11）

An extra-deep drawing steel for enameling was annealed at different temperatures using continuous annealing simulator. The mechanical properties, recrystallization texture, microstructure and second phase particles of the annealed steel were studied by tensile testing machine, X-ray diffractometer, optical microscope and transmission electron microscope (TEM). The results show that the recrystallization texture of the tested steel after annealing is mainly distributed in γ orientation line, the texture types are mainly {111}<110> and {111}<112>, which contributes to high r value. With the increase of annealing temperature, the r value increases, which is attributed to the increase in density of the {111}<110> and {111}<112> textures with the increase of annealing temperature. Among them, the {111}<110> texture is increased significantly in density, while the density increment of {111}<112> texture is very small or even reduced, where the former significant increment is attributed to the weakening of grain pinning effect on {111}<110>texture orientation caused by TiC particle coarsening. The coarsening of TiC particles is a necessary condition for the full development of {111}<110>oriented grains during the annealing process, and is an important factor for the steel plates to achieve excellent formability. Meanwhile, as the {111} texture density increases, the strength of the steel plate decreases, the elongation after fracture increases, and the formability improves.

Reference | Related Articles | Metrics

Select

Effect of annealing process on microstructure and hardness of hot-rolled 420U6 nitrogen-containing martensitic stainless steel

Jia Yuanwei

Heat Treatment of Metals 2024, 49 (3): 98-102. doi:10.13251/j.issn.0254-6051.2024.03.016

Abstract （12）

PDF （3347KB）（11）

After annealed at 800-950 ℃ for 8-48 h, the changes of microstructure and hardness of the hot-rolled 420U6 nitrogen-containing martensitic stainless steel under different annealing processes were studied by means of laser confocal microscope and Vickers hardness tester. The results show that the annealed microstructure is composed of ferrite matrix distributed with carbide, and the size and morphology of the carbide differ obviously under different heat processes. When annealed at 850 ℃ for 16-24 h, the carbide exhibits spheric shape and its size is generally uniform with average diameter of 0.4-0.5 μm. With the increase of annealing temperature and prolonging of holding time, the hardness of the tested 420U6 steel decreases at first and then increases slightly. The occurrence of lamellar carbide is responsible for the increase in hardness.

Reference | Related Articles | Metrics

Select

Control of core microstructure in hot rolled SWRH82B high carbon steel wire rod

Wang Jintao, Shen Kui, Li Zhanwei, Zhang Yu

Heat Treatment of Metals 2024, 49 (3): 103-107. doi:10.13251/j.issn.0254-6051.2024.03.017

Abstract （11）

PDF （2633KB）（10）

Effects of different spinning temperatures and different water tank water amount distributions (high-medium-low, high-low-high) on the microstructure and properties of SWRH82B high carbon steel wire rod were investigated. The results show that when the spinning temperature is increased to 910±10 ℃ and the water in the water tank is distributed according to high-low-high, the temperature difference between the core and the surface of the wire rod increases from 18 ℃ to 30 ℃, the cooling rate of the core of the wire rod is improved, the formation of network cementite is reduced, the detection rate of network cementite is reduced from 70% to 5%, and the grade of network cementite is reduced from grade E to grade C. At the position of 1/4 diameter of wire rod, the lamellar spacing of the sorbite decreases from 153 nm to 138 nm, and the tensile strength of wire rod increases from 1174 MPa to 1187 MPa. For continuous drawing the rod from Ø6.5 mm to Ø2.1 mm, the breaking rate is reduced from 9 times /100 t to 1 time /100 t, which effectively improves the drawing performance of hot rolled wire rod.

Reference | Related Articles | Metrics

Select

Effect of heat treatment on microstructure and mechanical properties of ZL201A aluminum steel shell with counter-pressure casting

Wang Yayong, Cao Xijuan, Ren Guangxiao, Liu Yongzhe, Zheng Yunkai

Heat Treatment of Metals 2024, 49 (3): 108-111. doi:10.13251/j.issn.0254-6051.2024.03.018

Abstract （14）

PDF （2327KB）（13）

Aiming at the technical problem that the mechanical properties of the ZL201A aluminum alloy could not meet the design and acceptance requirements during the trial production of a certain type of product, combining with the performance characteristics of the ZL201A binary alloy and the actual production experience, through the formulation of a reasonable heat treatment process plan, the effect of different heat treatment temperatures and time on the microstructure and properties of the ZL201A aluminum alloy under the condition of two-stage solid solution was investigated. The results show that with 535 ℃×9 h+545 ℃×9 h two-stage solid solution treatment and 160 ℃×6 h aging, the ZL201A aluminum alloy demonstrates best comprehensive mechanical properties with tensile strength 389 MPa, yield strength 342 MPa and elongation 11.5%. The testing results not only meet the technical requirements of product design acceptance, but also accumulate effective practical data for the subsequent material engineering application and system research.

Reference | Related Articles | Metrics

Select

Effect of tempering temperature on microstructure and properties of an oil casing steel used for deep wells

Wang Jiaojiao, Zhao Linlin, Gao Yunzhe, Shi Shuai, Wu Xiaolong, Zhao Yanqing, Zhou Yuqing, Gong Junjie

Heat Treatment of Metals 2024, 49 (3): 112-115. doi:10.13251/j.issn.0254-6051.2024.03.019

Abstract （12）

PDF （3596KB）（19）

Effect of tempering temperature on the microstructure and mechanical properties of a deep well oil casing steel quenched at 920 ℃ was studied by means of optical microscope (OM), scanning electron microscope (SEM) and tensile testing machine. The results show that the experimental steel obtains tempered martensite structure after tempered at 500-600 ℃, which has high product of strength and elongation and high toughness, where the product of strength and elongation is ranged from 20.5 to 22.1 GPa·%, and the impact absorbed energy is ranged from 94.6 to 100.3 J. When the tempering temperature is 550 ℃, the deep well oil casing experimental steel has the best comprehensive mechanical properties, with tensile strength of 978 MPa, yield strength of 935 MPa, and product of strength and elongation of 22.1 GPa·%, impact absorbed energy is 100.3 J.

Reference | Related Articles | Metrics

Select

Effect of rapid annealing on microstructure and properties of cold rolled ultra-low carbon steel

Zhang Rui, Tang En, Yuan Qing, Ren Jie, Mo Jiaxuan

Heat Treatment of Metals 2024, 49 (3): 116-121. doi:10.13251/j.issn.0254-6051.2024.03.020

Abstract （9）

PDF （2959KB）（12）

Conventional annealing process (long time at low temperature) and rapid annealing process (instantaneous at high temperature) were compared and analyzed from four aspects of microstructure, grain size distribution, grain orientations and mechanical properties of cold rolled ultra-low carbon steel by means of OM, SEM, EBSD and uniaxial tensile test. The results show that after rapid annealing at 650 ℃ for 15 s, the yield strength and tensile strength of the tested steel are 445.38 MPa and 494.07 MPa, respectively, which are obviously increased from that of conventional annealed (i.e., the yield strength and tensile strength being 274.35 MPa and 388.99 MPa, respectively), while the elongation is still guaranteed up to 24.7%. The grain refinement and the typical γ orientation are the main reasons for the difference of properties between the conventional and rapid annealed specimens, where the grain refinement is the dominant. The rapid annealing has a higher grain refinement strengthening effect, but it deteriorates the work hardening ability and leads to a decrease in elongation. In addition, the rapid annealing inhibits the precipitation of the second phase particles while refines them. By comparison, the rapid annealed specimens show a typical γ orientation, which is more conducive to improving the rolling performance, but that by conventional annealing show a near γ orientation which has less such effect.

Reference | Related Articles | Metrics

Content of PROCESS RESEARCH in our journal