A nonlinear finite element model of vacuum heat treatment process was developed. In this model, influence of many factors, such as nonlinear heat radiation, temperature-dependent thermal physical properties of materia...A nonlinear finite element model of vacuum heat treatment process was developed. In this model, influence of many factors, such as nonlinear heat radiation, temperature-dependent thermal physical properties of material are considered. The temperature field of GH4169 alloy workpiece during vacuum heat treatment process was calculated using finite element software MSC.Marc, and the thermal hysteresis time of the workpiece was predicted. An experiment of vacuum heat treatment of GH4169 superalloy workpiece was carried out to verify the calculation. The experimental results of temperature profile agree well with the simulated results. This work lays a theoretical foundation for optimizing technical parameter of vacuum heat treatment process.展开更多
A system was developed to identify characteristics of quenchants. It consists of computerized hardware, temperature acquisition software as well as changeable probes of steels. The feature of the ability to use probes...A system was developed to identify characteristics of quenchants. It consists of computerized hardware, temperature acquisition software as well as changeable probes of steels. The feature of the ability to use probes made of any metallic material enables evaluation of hardening power of quenchants. Three thermal couples located on the same cross-section plane in the middle of probe’s length give cooling curves that present cooling behavior at different depths from the surface of probe. Microstructure and hardness of the quenched probes on the same plane in the middle of probe’s length from surface to center was investigated to estimate hardening effect. A number of quenchants were tested by this characterization system with several thermal probes of typical steels. Experimental data were stored in QuenDB quenchant database, which was designed for quenchants identification and hardness distribution storage.展开更多
文摘A nonlinear finite element model of vacuum heat treatment process was developed. In this model, influence of many factors, such as nonlinear heat radiation, temperature-dependent thermal physical properties of material are considered. The temperature field of GH4169 alloy workpiece during vacuum heat treatment process was calculated using finite element software MSC.Marc, and the thermal hysteresis time of the workpiece was predicted. An experiment of vacuum heat treatment of GH4169 superalloy workpiece was carried out to verify the calculation. The experimental results of temperature profile agree well with the simulated results. This work lays a theoretical foundation for optimizing technical parameter of vacuum heat treatment process.
文摘A system was developed to identify characteristics of quenchants. It consists of computerized hardware, temperature acquisition software as well as changeable probes of steels. The feature of the ability to use probes made of any metallic material enables evaluation of hardening power of quenchants. Three thermal couples located on the same cross-section plane in the middle of probe’s length give cooling curves that present cooling behavior at different depths from the surface of probe. Microstructure and hardness of the quenched probes on the same plane in the middle of probe’s length from surface to center was investigated to estimate hardening effect. A number of quenchants were tested by this characterization system with several thermal probes of typical steels. Experimental data were stored in QuenDB quenchant database, which was designed for quenchants identification and hardness distribution storage.
