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Simulation and calculation of heat treatment parameters and thermophysical properties of 16CrSiNi steel using JMatPro software

Ma Luyi, Du Qingyin, Li Shijian, Yang Lixin, Liu Gang, Wang Xinyu

Heat Treatment of Metals 2024, 49 (7): 42-46. doi:10.13251/j.issn.0254-6051.2024.07.007

Abstract （136）

PDF （2973KB）（96）

Thermodynamic equilibrium phase composition, Jominy hardenability, phase transition, thermophysical properties and mechanical properties after quenching and tempering of the 16CrSiNi steel were simulated by using JMatPro software, and the thermodynamic equilibrium phase compositions, hardenability curves, TTA curves, TTT curves, CCT curves, quenching microstructure, mechanical properties after quenching and tempering, thermophysical properties under different temperatures as density, thermal conductivity, Young's modules, specific heat, Poisson's ratio and enthalpy were obtained.

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Numerical simulation of temperature uniformity of hub bearing inner ring during induction tempering process

Wei Wenting, Zhao Tianyi, Ke Jinzhe, Liu Qinglong

Heat Treatment of Metals 2023, 48 (5): 129-137. doi:10.13251/j.issn.0254-6051.2023.05.021

Abstract （113）

PDF （3417KB）（44）

Coupling calculation simulation model of electromagnetic field and temperature field was used to study the influence of induction heating process parameters on tempering temperature field of inner ring of the special-shaped automobile wheel hub bearing, and the interaction of the induction tempering process parameters was analyzed by using the response surface methodology. The results show that as the frequency and current density of the induction coil decrease, the temperature difference between the core and the surface of the bearing inner ring decreases, and the overall heating rate decreases. According to the significance of the influence on temperature difference and heating rate, the order of induction heating process parameters is current density, frequency, and air gap. Induction tempering process parameters with better temperature uniformity obtained based on response surface method are the frequency of 10 kHz, the current density of 19.6×10⁶ A/m², the air gap between the outer induction coil and the parts of 8.5 mm, and the effectiveness of temperature field numerical simulation is verified through experiments. With equivalent tempering parameters, isothermal tempering and induction tempering experiments find that the hardness obtained by the two processes is similar.

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Numerical simulation of vacuum isothermal quenching process of H11 steel large module for die-casting dies

Tu Yujie, Li Bingchen, Chen Hao, Wu Xiaochun

Heat Treatment of Metals 2024, 49 (7): 1-8. doi:10.13251/j.issn.0254-6051.2024.07.001

Abstract （102）

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Based on the metal-thermo-mechanical coupled theory, multi-field coupled numerical models of the H11 steel large module (500 mm×500 mm×500 mm) during vacuum isothermal quenching was established, and the numerical simulation of different vacuum isothermal quenching processes was carried out to study the evolution of the temperature field, structure field and stress field. The results show that compared with direct quenching, isothermal quenching can effectively reduce the temperature difference and the stress between the core and surface during the cooling process of the module to avoid the risk of distortion and cracking. Vacuum isothermal quenching can increase the volume fraction of bainite in the core of the module while avoiding pearlite formation and carbides precipitating along the grain boundary, and with the increase of the isothermal time, the more core bainite will be generated. The experimental verification of vacuum isothermal quenching at 500 ℃ for 1 h carried out by using industrial equipment indicates that the temperature curves at different positions of the module are in good agreement with the simulation results, and the type of bainite formed in the core of the module after vacuum isothermal quenching is lower bainite with good toughness.

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Simulation of thermal compression and texture evolution of TB6 titanium alloy

Mo Hongsheng, Cui Xia, Zhu Enrui, Ouyang Delai, Yang Chao

Heat Treatment of Metals 2024, 49 (7): 29-37. doi:10.13251/j.issn.0254-6051.2024.07.005

Abstract （95）

PDF （6396KB）（67）

Thermal deformation behavior of TB6 titanium alloy under different deformation conditions (deformation temperature of 1173-1323 K, strain rate of 0.001-1 s^-1) was studied by means of Thermecmaster-Z thermal simulator. Hot compression process was stimulated by finite element simulation software, and stress and strain distribution under different deformation conditions was analyzed. The results show that stress-strain curves obtained by numerical simulation is consistent with the experimental values. Finite element software is conducted secondary development and the ODF diagram of the compressed alloy is simulated, which has a high degree of agreement with the measured ODF diagram. The distribution of equivalent stress and equivalent strain is uneven, and the maximum stress and maximum strain occur at the center of the specimen. The stress and strain increase with the decrease of deformation temperature or the increase of strain rate. After hot compression, the main texture of the alloy is R-Cube_ND {001}<110>texture and Cube {001}<100>texture, and it has a certain degree of heritability. Increasing the deformation temperature or strain rate can strengthen the main texture.

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Numerical simulation and experimental verification for quenching process of 2A14 aluminum alloy components

Deng Xiaofeng, Yang Yuchen, Shi Wei

Heat Treatment of Metals 2024, 49 (4): 223-228. doi:10.13251/j.issn.0254-6051.2024.04.036

Abstract （91）

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In order to predict the residual stress and deformation of 2A14 aluminum alloy after quenching, a material model of the 2A14 aluminum alloy during quenching was established with thermal expansion test, high temperature tensile test and material computation method. Based on the on-line measured temperature change during quenching process and the residual stress value after quenching measured by XRD, the surface heat transfer coefficient of the C-ring specimen during quenching was calculated by inverse heat transfer method, and the changes of the temperature, stress and opening distance of the C-ring during quenching process were simulated and calculated. The simulation results shows that the increase of the opening distance of the C-ring after quenching is 0.1158 mm, and the actual measurement is 0.1657 mm, which show that the calculated results are in good agreement with the measured results.

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Numerical simulation of temperature uniformity of large thin-walled shell parts during high pressure gas quenching

Wang Jing, Zhang Xiaojuan, Tong Daming, Gu Jianfeng, Zhou Zhongping, Bai Lu, Zhu Lijian

Heat Treatment of Metals 2024, 49 (7): 9-15. doi:10.13251/j.issn.0254-6051.2024.07.002

Abstract （79）

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Fluid-solid coupling simulations were carried out for the large thin-walled shells during high pressure gas quenching. The numerical model was included the vacuum high-pressure gas quenching furnace and the large thin-walled shells which were aerospace components. The temperature uniformity of the shell during high pressure gas quenching in the vacuum furnace was evaluated, and the shell temperature distribution was simulated corresponding to the different gas outlet positions, different furnace charging and flow diversion conditions. The results show that compared with the original model, the quenching methods of one-outlet scheme, one-shell charging in the center of furnace and adding baffles can improve the temperature uniformity of the shell by 8%, 30% and 12.5% respectively, and the results provide an optimized quenching scheme for controlling the deformation of the shell.

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Numerical simulation of spiral bevel gear quenching based on thermo-fluid-solid coupling model

Liu Ganhua, Deng Shiyi, Huo Xiaodong

Heat Treatment of Metals 2024, 49 (7): 16-21. doi:10.13251/j.issn.0254-6051.2024.07.003

Abstract （68）

PDF （2435KB）（86）

Based on thermo-fluid-solid coupling simulation, quenching and cooling process of 45 steel spiral bevel gears was numerical simulated, and the influence of quenching medium flow rate on quenching results was studied. It is found that the maximum relative errors between the cooling curves of thermo-fluid-solid coupling simulation and traditional simulation and experimental measurement are 9.2% and 7.4%, respectively. Moreover, more accurate prediction of temperature distribution under quenching medium flow conditions is achieved, verifying the accuracy and convenience of this method. When the inlet flow rate is 2 m/s, the maximum hardness value is 52.0 HRC, and the residual stress is mainly favorable compressive stress.

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Optimization of heat treatment process of bainitic rails based on simulation software

Chen Yanzi, Liu Xinyu, Su Hang, Xie Benchang, Cen Yaodong, Chen Lin

Heat Treatment of Metals 2024, 49 (7): 38-41. doi:10.13251/j.issn.0254-6051.2024.07.006

Abstract （64）

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DEFORM finite element software was used to simulate the quenching process of bainitic rails, and the microstructure and hardness of the rails were compared with that of the actual quenched rails to study the accuracy of the finite element simulation. The test results show that after simulated quenching, the hardened layer thickness at the rail head is 12 mm, and the hardness is 40.42-42.23 HRC, which are similar to the actual measured hardened layer thickness of 11 mm, and the hardness of 40.20-43.40 HRC, respectively. Using the color metallographic method and Image-Pro software, the bainite content at the rail head is about 63.80%, and the martensite+retained austenite content is about 36.20%. Compared with the simulation results (bainite content of 57.7%, martensite+retained austenite content of 42.3%), the errors are all around 6%. The accuracy of finite element simulation results is confirmed, which can be used to guide the actual production.

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Numerical simulation of laser hardening of 40Cr steel hob textured surface

Zhang Shuaikun, Zhang Chaoyong, Wu Jianzhao, Tang Limei

Heat Treatment of Metals 2024, 49 (5): 47-54. doi:10.13251/j.issn.0254-6051.2024.05.008

Abstract （62）

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Numerical simulation was conducted on the textured surface of 40Cr steel shield tunneling cutter after laser hardening. By simulating the temperature changes during laser hardening, the phase transformation caused by temperature changes during laser hardening was analyzed, as well as the formation mechanism of the laser hardened layer. The morphology of the hardened layer on the 40Cr steel shield tunneling cutter after laser hardening was observed. Friction and wear tests were projected on 40Cr steel, 40Cr steel shield tunneling cutter textured surface, and laser hardened 40Cr steel shield tunneling cutter textured surface to study their friction and wear properties. The results show that there is a parallel groove like texture on the surface of the 40Cr steel shield tunneling cutter. This texture and laser hardening can effectively improve the wear resistance of the cutter. After laser hardening, the textured surface of the shield tunneling cutter has the highest wear resistance, with a cross-sectional worn area of 47.3% of the textured surface of the shield tunneling cutter and 37.3% of the non textured surface of the 40Cr steel. The finite element numerical simulation is reliable and laser hardening can effectively improve the wear resistance of the shield tunneling cutter.

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Numerical simulation and microstructure analysis of post-weld heat treatment for TC4 titanium alloy

Xie Benchang, Liu Xinyu, Zhang Le, Chen Yanzi, Cen Yaodong, Chen Lin

Heat Treatment of Metals 2024, 49 (8): 242-247. doi:10.13251/j.issn.0254-6051.2024.08.041

Abstract （59）

PDF （3808KB）（46）

Ansys software was used to simulate the welding and post-weld heat treatment(PWHT) process of the TC4 titanium alloy, and the changes of microstructure and residual stress of the welded and heat treated alloy were analyzed. The results show that during the welding process, the temperature of each layer of the weld varies due to different heat inputs. The peak temperature of the first layer weld is the lowest (2183.6 ℃), and the fifth layer is the highest (2337.8 ℃). Due to the different characteristics of thermal cycles experienced by each layer, the size of martensite in each layer of the weld zone changes from 19.5 μm to 96.2 μm. The weld zone after welding is mainly composed of α_m phase, a small amount of β phase, some α_t phase and precipitated α_g phase. After the PWHT, the α_m phase in the joint transforms into a secondary (α+β) phase, and it is XRD observed that the (0002)_α diffraction peak undergoes peak splitting, a new peak (110)_β appears at 2θ=39.6°, the full width at half maximum decreases by 5.56%-43.75%, indicating that the crystallinity of TC4 titanium alloy is improved with the elimination of residual stress. The residual stress after welding is mainly concentrated near the weld seam, which is a fracture prone location. The residual stress along the direction perpendicular to welding is symmetrically distributed, which is basically the same as the distribution of temperature field. After the PWHT, all the residual stresses are reduced.

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Analysis and distortion control optimization of carburization and quenching for spacecraft gears

Yang Kai, Wang Pengpo, Zhang Yumei, Zeng Hong, Zhang Bin, Wang Tianming, Ma Yuliang, Wang Yanzhong

Heat Treatment of Metals 2024, 49 (7): 22-28. doi:10.13251/j.issn.0254-6051.2024.07.004

Abstract （58）

PDF （4477KB）（60）

According to the chemical composition of the steel for a spacecraft power gear, the thermal-physical property parameters of the material were calculated by means of JMatPro simulation software. Based on the gear model and heat treatment process parameters, carburizing and quenching simulation analysis was carried out in Deform finite element software to determine the change of carbon content on the tooth surface during carburizing process, and the change of microstructure of the gear teeth during quenching process. Finally, according to the characteristics of herringbone gears and the precision control requirements of spacecraft gears, the distortion of the gear teeth after quenching is optimized by changing the quenching process parameters. The results show that when the quenching process is pre-cooling in air for 30 s, quenching in hot oil at 80 ℃ for 1200 s and then deep cooling at -100 ℃ for 7200 s, the amount of distortion is controlled better and meets the product requirements.

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Control and parameter optimization in electromagnetic induction heating temperature uniformity of large thick-walled cylinder

Dong Jiaxin, Luo Yun, Jiang Wenchun, Gu Wenbin, Dong Pijian

Heat Treatment of Metals 2024, 49 (3): 275-278. doi:10.13251/j.issn.0254-6051.2024.03.045

Abstract （58）

PDF （2632KB）（30）

Based on the electromagnetic induction heat treatment experiment of 100 mm thick-walled cylinder of Ø1900 mm with external diameter, a step-type temperature rise control method was designed, and the influence of different induction heating parameters on temperature field of local heat treatment of cylinder was analyzed, and the optimal electromagnetic induction heating parameters were obtained. The results show that, according to the technical requirements of the holding temperature of 595-620 ℃, the best designed parameters are that the 20 mm diameter induction cable is selected with the induction coil number of 16, the width of the outer wall insulation is 1460 mm, the inner wall is fully insulated, and the turn spacing of 32 mm is the best design parameters. The larger the current frequency of the induction heating, the faster the heating rate of the cylinder surface. In order to maintain temperature uniformity, it is recommended to choose a smaller frequency of 2 kHz within the appropriate range.

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Numerical simulation of microstructure and distortion evolution behavior of C-type specimens during carburizing and quenching

Xu Yong, Liu Ke, Deng Yaoyao, Yang Bing, Lu Hailong, Luo Yi

Heat Treatment of Metals 2024, 49 (5): 68-73. doi:10.13251/j.issn.0254-6051.2024.05.011

Abstract （53）

PDF （3860KB）（48）

Taking C-type specimen of 18Cr2Ni2MoNbA steel as the study object, the microstructure and distortion evolution behavior of the C-type specimens under suspension during carburizing and quenching were studied by using finite element method to establish a multi-field coupling model of temperature field, structure field and strain field. The results show that the calculated distortion results are in good agreement with the actual measurements. The maximum distortion is at the notch position of the C-type specimen. The maximum temperature difference between the center position of the maximum width and the surface position of the notch during cooling process appears at 2.78 s and reaches 383.437 ℃. The martensitic transformation first starts from the core of the notch position, and the content of martensite in the core of C-type specimen can generally reach over 94%. During quenching, the surface martensite transformation of the C-type specimen lags behind the core, the surface martensitic transformation content is significantly lower than that of the core under the influence of retained austenite, and the final transformation content is about 83%.

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Effect of nano-cracks on heat conduction and ion diffusion of 8YSZ thermal barrier coatings

Chen Yuhui, Sun Jiaxiang, Jiang Pengyang, Chai Zonghua, Zhang Baiqiang

Heat Treatment of Metals 2024, 49 (6): 248-253. doi:10.13251/j.issn.0254-6051.2024.06.039

Abstract （52）

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Effect of nano-cracks on thermal transport properties and ion diffusion of 8YSZ (8mol% Y₂O₃, stabilizing ZrO₂) thermal barrier coating at 1473 K was studied by means of non-equilibrium molecular dynamics method. The effects of crack location, crack length and crack number on thermal conductivity and ion diffusion of the 8YSZ thermal barrier coating were described. The results show that the thermal conductivity of the material with the nano-cracks cross wise arrange on both sides of the model is lower than that with the cracks evenly distribute along the heat flow direction on the same side of the model, but the crack location distribution has a little effect on the diffusion of O^2-. With the increase of crack length or number, the thermal conductivity decreases and the O^2- migration slows down. It is found that small cracks with a large number and uniform distribution have a stronger inhibition on the thermal transport of the 8YSZ thermal barrier coating than those with a small number and long length.

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Numerical simulation and experiment on vacuum gas quenching of H11 steel large die cast module

Chen Hao, Tu Yujie, Jiang Zhipeng, Wu Xiaochun

Heat Treatment of Metals 2024, 49 (2): 227-235. doi:10.13251/j.issn.0254-6051.2024.02.037

Abstract （52）

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Effect of quenching pressure on temperature field, microstructure field and stress field of the H11 steel module (500 mm×500 mm×500 mm) during air quenching were studied by combining numerical simulation with experiment. The results show that greater quenching pressure, better cooling effect, but at the same time, it also causes greater quenching stress which can increase the risk of cracking. The overall cooling rate of the module increases as the quenching pressure increases, in the high temperature transformation zone (600-800 ℃), the maximum cooling rate of the module core under quenching pressure of 8 bar is 0.20 ℃/s, which is 0.06 ℃/s higher than that of 4 bar. The maximum stress of the module under quenching pressure of 8 bar and 4 bar is 655 MPa and 437 MPa, respectively. Through experiment verification, the carbides precipitated along the grain boundary appear in the core of the module under quenching pressure of 4 bar, therefore during the gas quenching process of H11 steel large modules, the cooling rate at the core should be at least ≥ 0.16 ℃/s at 600-800 ℃.

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Numerical simulation of low pressure carburizing process for 20CrMnTi steel

Deng Xiaohu, Song Wenjuan, Fan Yuanyuan, Guo Jingyu, Wang Huizhen, Zhou Leyu, Xu Yueming, Ju Dongying

Heat Treatment of Metals 2024, 49 (8): 220-224. doi:10.13251/j.issn.0254-6051.2024.08.038

Abstract （51）

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Based on the principle of multiple factors such as temperature, diffusion, phase transformation and stress, finite element simulation technology was used to simulate and analyze the carburizing process of 20CrMnTi steel under low pressure environment. The simulation process fully considered the boundary condition characteristics of the alternating strong infiltration and diffusion in the low pressure carburizing process, and the strong infiltration and strong infiltration+diffusion were simulated separately, the carbon concentration, martensite volume fraction and hardness distribution were obtained. The results indicate that as the diffusion time increases, the surface carbon concentration of the specimen decreases and the depth of the carburized layer increases. The simulation results of carbon concentration distribution after carburizing are in good agreement with the experimental results, indicating high simulation accuracy. The volume fraction of martensite and hardness of the carburized layer after low pressure carburizing under strong infiltration+diffusion process are simulated, and the distribution of the two is consistent. Comparing the simulation and experimental results of hardness of the specimen after low pressure carburizing under strong infiltration + diffusion process, the measured value is slightly higher than the simulated value, because the simulation result is the calculated average of a larger area.

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Numerical simulation and experimental verification of heat treatment after forging of SA508-3 steel for steam generator

Feng Xingwang, Zhang Ke, Liu Jiujiang, Shi Ruxing, Su Wenbo, Liu Shuai, Li Zhipeng, Yang Bin

Heat Treatment of Metals 2024, 49 (5): 55-61. doi:10.13251/j.issn.0254-6051.2024.05.009

Abstract （50）

PDF （4118KB）（40）

Taking SA508-3 steel forging for steam generator as research object, the thermophysical parameters for the steel were calculated by JMatpro software. After heat treatment, the microstructure and hardness of the forging were simulated by Deform-3D software. And the experimental verification was carried out by small specimen physical simulation method. The results show that the microstructure and hardness of both the experimental test and numerical simulation are in good agreement. It can be seen that numerical simulation technology is an effective tool to determine the rationality of heat treatment process for large forgings, which has significant value in shortening production cycle and reducing cost.

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Simulation and experiment analysis of bainite quenching of bearing ring

Zhou Ruihu, Zeng Zhipeng

Heat Treatment of Metals 2023, 48 (12): 277-280. doi:10.13251/j.issn.0254-6051.2023.12.045

Abstract （50）

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Effect of bainite isothermal quenching process on the distorsion and fracture toughness of GCr15 steel bearing rings was analyzed by using finite element simulation and experimental methods, where the numerical simulation of the bainite quenching process for bearing rings was carried out by using Deform-3D software. Taking cylindrical roller bearing NJ308 as the research object, the maximum distorsion after simulated heat treatment is 0.08 mm. Compared with the experimental results, the simulation error is 14%. Based on the bainite quenching process experiment, the distorsion of the bearing diameter is measured to be 0.07 mm, which is much smaller and more uniform than that after the conventional martensite quenching, and is beneficial for subsequent grinding processing. The fracture test results show that the fracture strength of the bearing rings after conventional martensite quenching and tempering process is 113.3 kN, while that after the bainite quenching treatment is significantly improved to 152.7 kN.

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Microstructure evolution and temperature field simulation of Inconel 718 super alloy during isothermal compression

Wang Chao, Ren Yonghai, Han Senlin, Cheng Zhi, Wang Longxiang, Zhao Fei, Tan Yuanbiao

Heat Treatment of Metals 2023, 48 (5): 151-157. doi:10.13251/j.issn.0254-6051.2023.05.024

Abstract （50）

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Microstructure evolution and temperature field simulation of the Inconel 718 superalloy in the temperature range of 950-1150 ℃ and strain rate range of 0.1-10 s^-1 were investigated by means of Gleeble 3800 thermal compression tester, Deform-3D finite element software and optical microscope. The results show that at low deformation temperature and high strain rate, the flow stress increases rapidly to the peak at the initial stage with the increase of deformation strain. After reaching the peak stress, the flow curve exhibits an obvious softening phenomenon. Also at low deformation temperature and high strain rate, the deformation heat is larger, leading to a fact that dynamic recrystallization is prone to occur in the deformed alloy, the dynamic recrystallization degree is higher, and the grain size is smaller. As the strain rate decreases, the deformation heat decreases gradually, and the volume fraction of dynamic recrystallization grains decreases. When deformed at 1100 ℃ and 0.1 s^-1, the full dynamic recrystallization occurs in the deformed alloy. Based on the results of the temperature field distribution simulated by Deform-3D software, it can be seen that the hot deformation conditions of low temperature and high strain rate will produce large deformation heat in the deformed alloy. With the increase of deformation temperature and the decrease of strain rate, the value of deformation heat gradually decreases. When the deformation temperature and strain rate are constant, the deformation heat in the alloy increases with the increase of true strain.

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Numerical simulation of charging coefficient for heat treatment of stainless steel bars with different cross sections

Liu Gang, Ren Jinyi, Yang Lixin, Ma Luyi, Li Changsheng

Heat Treatment of Metals 2024, 49 (6): 254-260. doi:10.13251/j.issn.0254-6051.2024.06.040

Abstract （49）

PDF （5916KB）（38）

For three different cross sections of stainless steel bars(square, round and hexagonal) under vacuum furnace thermal radiation conditions, finite element simulation combined with heat transfer principles was used to construct a standard sample library by using the "equivalent circular bar diameter comparison method". A study was conducted on the determination method of charging coefficient, and mathematical models were established for the loading spacing and charging coefficient of heat treatment in different fields. The results show that as the loading distance increases, the adjacent diameters, conditional thicknesses and charging coefficients of the three different shapes of stainless steel bars gradually decrease. Comparing the charging coefficient, it can be found that the charging coefficients of tightly arranged round stainless steel bars and hexagonal stainless steel bars are significantly smaller than that of the square stainless steel bars. In the actual production of stainless steel bars, under the condition of strictly following the provisions of the charging coefficient and calculating the correct conditional thickness, the bars can be arranged tightly without leaving gaps during furnace charging.

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