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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 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）

PDF （5794KB）（126）

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 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）

PDF （5705KB）（68）

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）

PDF （4530KB）（40）

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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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 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）

PDF （2021KB）（22）

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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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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Numerical simulation on influence of post-weld heat treatment on residual stress in 150 mm thick vessel steel plate

Shi Hongchang, Huang Anming, Liu Xing, Qiang Bin

Heat Treatment of Metals 2024, 49 (5): 62-67. doi:10.13251/j.issn.0254-6051.2024.05.010

Abstract （46）

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Post-weld heat treatment (PWHT) can effectively reduce residual stress in welded joint. The residual stress field before and after PWHT for 150 mm thick vessel steel butt-welded joint was simulated by using finite element analysis. The evolution of residual stress during PWHT was systematically analyzed, and a comparative analysis was conducted on the residual stress relief effect of relevant PWHT process parameters. The results indicate that the PWHT significantly reduces the peak values of longitudinal and transverse residual stresses, but the impact on the distribution pattern of residual stress is relatively small. Stress relief primarily occurs during the heating stage of the treatment, with minimal relief or even rebound during the soaking and cooling stages. The analysis of process parameters reveals a nonlinear evolution of stress relief with changes in soaking time and heating temperature. Therefore, practical PWHT should consider the combined effects of influencing factors to optimize stress relief effectiveness and cost.

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Application of model-free adaptive control in heat treatment of large 12Cr2Mo1V steel

Gao Xinbo, Qin Qingliang

Heat Treatment of Metals 2024, 49 (9): 290-296. doi:10.13251/j.issn.0254-6051.2024.09.049

Abstract （42）

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For the heating and post-welding heat treatment of large-diameter thick-walled 12Cr2Mo1V steel, the medium-frequency induction heating method was adopted and the model-free adaptive control (MFAC) algorithm replacing the traditional PID algorithm was selected for temperature control. Firstly, the physical parameters of the workpiece were analyzed, and parameters such as heating frequency, coil current, and power configuration were calculated. Then, the obtained parameters were input into COMSOL software to simulate on-site conditions and perform magnetic-thermal coupled simulation analysis, validating the feasibility of the calculated data. Next, the MFAC architecture was constructed in the SIMULINK simulation platform and compared to the traditional PID method, and the two algorithms were actually applied to observe the heating effect in the field. The results show that when large workpieces are heated to the target temperature of 700 ℃, the temperature fluctuation is smaller, the stability is higher, and the uniformity is better.

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Failure analysis and laser surface composite treatment of piercing plug for seamless steel pipe based on FEM simulation

Mu Jian, Wu Hebao, Zhang Xun, Li Xiaolong, He Yin, Li Jianjun

Heat Treatment of Metals 2024, 49 (9): 284-289. doi:10.13251/j.issn.0254-6051.2024.09.048

Abstract （41）

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Finite element method (FEM) was used to analyze the temperature field, stress field, and thermo-mechanical coupling field of the piercing plug, and the maximum thermo stress, maximum coupling stress, maximum surface temperature, stress concentration area, and fatigue crack type were determined. And laser cladding+high-temperature slow oxidation composite treatment was carried out on 20Cr2Ni4 steel to improve the mechanical properties and high-temperature resistance of the plug. The FEM simulation results show that the thermo-mechanical coupling stress of the plug is the vector sum of thermo tensile stress and mechanical compressive stress. The coupling stress is dropped by about 5.7% compared with the peak value of thermo stress. The value of thermo-mechanical coupling stress is mainly affected by thermo stress, and the changing trend and distribution are mainly affected by mechanical stress. the failure of the plug originates from the crack source on the inner surface under the combined action of thermo fatigue and mechanical fatigue, and propagates radially outward to form fatigue cracks on the surface. The results of laser surface composite treatment show that after laser cladding and high temperature slow oxidation treatment, the surface hardness of 20Cr2Ni4 steel can reach 494 HV0.025, the surface strengthening layer is firmly bonded to the matrix, and the content of oxygen element in the matrix is less and more evenly, which effectively improves the service life of the plug.

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Numerical analysis of flow field in an atmosphere-controlled furnace under different stirring fans based on ANSYS

Shu Dongfang, Luo Cheng, Shi Lei

Heat Treatment of Metals 2024, 49 (11): 278-283. doi:10.13251/j.issn.0254-6051.2024.11.043

Abstract （39）

PDF （4846KB）（16）

Based on FEM numerical analysis, the flow field in atmosphere-controlled sealed box furnace with different stirring fans was simulated, and by using transient and steady-state methods, the flow velocity, static pressure and dynamic pressure changes inside the controlled atmosphere furnace were analyzed under the conditions of a four blade stirring fan (Fan4) and a six blade stirring fan (Fan6). The airflow path inside the Fan4 furnace is relatively uniform, and they are all located in the upper non-working area of the furnace. The airflow path inside the Fan6 furnace is prone to forming vortices, which have a significant impact on the uniformity of furnace temperature and atmosphere. The dynamic pressure cloud diagrams inside Fan4 and Fan6 furnaces are basically similar, and the difference in dynamic pressure within the working area is relatively small. The static pressure inside the Fan6 furnace is generally higher than that of Fan4, and under the same conditions, a six blade fan will cause the furnace pressure to be too high.

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Computational method for unsteady heat transfer on surface of 45 steel during laser quenching

Zhang Wen, Guo Yutong, Zhang Lingcong, Shen Rui, Shi Hui, Bao Hanwei, Li Gangyan

Heat Treatment of Metals 2024, 49 (8): 232-241. doi:10.13251/j.issn.0254-6051.2024.08.040

Abstract （38）

PDF （5824KB）（26）

Temperature distribution of unsteady heat transfer during laser quenching of 45 steel was obtained by solving an explicit two-dimensional finite difference equation, and the effect of laser power on the surface temperature after single pass laser quenching was analyzed. Utilizing JMatPro, comprehensive phase transformation curves, as well as temperature-dependent thermophysical properties and phase transformation critical temperatures during heating and cooling processes of the material, were derived. Incorporating both the laser heat source and latent heat of phase transformation, a unsteady heat transfer model for the surface laser quenching of 45 steel was established. This model was then employed to conduct heat transfer analysis under both fixed and moving heat source conditions during laser quenching. The results show that the error of the maximum temperature calculation under fixed heat source condition is within 7%. When the laser irradiation time is 0.5 s and the power is between 1300 W and 2600 W, the surface temperature of the specimen can be effectively controlled between 720 ℃ and liquidus 1495 ℃, ensuring the occurrence of solid phase transformation during laser quenching process. The model is applied to single pass moving heat source laser quenching at high power, which can better reflect the actual temperature change trend.

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Temperature field simulation of liquid nitrogen assisted laser cladding and analysis of friction and wear property of clad layer

Wang Kaiming, Jiang Fulin, Bu Shanfei, Wang Chao, Jiang Zhiyong, Liu Qingyu

Heat Treatment of Metals 2024, 49 (6): 239-247. doi:10.13251/j.issn.0254-6051.2024.06.038

Abstract （38）

PDF （5957KB）（36）

Aiming at the process of preparing high-entropy alloy coating by liquid nitrogen assisted laser cladding, the temperature gradient and cooling rate of the clad layer under different liquid nitrogen application modes were analyzed by means of finite element analysis and experimental verification, and the theoretical basis of the influence of liquid nitrogen on the temperature gradient and cooling rate of the clad layer was revealed. The finite element simulation results show that when the laser power is fixed, the addition of liquid nitrogen assisted technology accelerates the cooling rate of the clad layer, increases the temperature gradient and reduces the residual stress. The maximum cooling rate is 8900 ℃/s, which is 1.505 times than that of air cooling. When the applied liquid nitrogen is fixed, the increase of laser power increases the temperature gradient of the clad layer and accelerates the cooling rate. The experimental results show that the addition of liquid nitrogen in the process of liquid nitrogen assisted laser cladding increases the hardness of the clad layer. When the laser power is 1500 W, the hardness increase is the most obvious, which is 1.3 times than that of air cooling. The friction coefficient of the clad layer is reduced, the average friction coefficient of the clad layer is 0.146, 0.256, 0.375, 0.351 and 0.382 at laser power of 1100-1900 W, which is lower than the average friction coefficient under air cooling condition. The wear volume of the clad layer is reduced. At laser power of 1700 W, the wear volume reduction is the most compared with that under air cooling condition, up to 55.4%, which improves the friction and wear property of the clad layer.

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