Numerická simulácia ochladzovania ložiskových krúžkov vyrobečných z ocele 100Cr6

Simulation of Quenching of Ball Bearing Rings Made from 100Cr6 Steel

přednáška

en

Thermal regime simulation with varying hardening temterature of three modes of oil quenching of ball bearing rings made of 100Cr6 steel was caried out in Sysweld program, based on finite element analysis. 3D model was prepared acording to manufacturing documentations of rough machined external rings. Hardening temperatures used 830, 850 and 870 degree celzius. As result complete graphical description of temperature, phase composition and hardness depending on time of quenching has been obtained. The results were compared with experimental heat treatment caried out with the same parameters. Comparison showed slight differences in hardness after quenching. In range of hardening temperatures applied, the observed microstructure consists of undisolved secondary cementite the volume fraction of which is depending on a number of parameters like heating speed, hardening temperature, holding time etc. This parameters have direct impact on microstructure and hardness after quenching. Sysweld software which was originaly created for simulation of welding of usual hypoeutectoid steels, is unable to predict secoundary cementite dissolution kinetics and therefore is not well suited for hardness and microstructure predictions for hypereutectoid steels in general. Nevertheless the time-temperature predictions and mechanical stress analysis can be very usefull for precise technological adjustments in industrial applications to prevent cracking or excessive deformation.

V programe Sysweld využívajúcom metóu konečných prvkov boli vytvorené tri simulácie ochladovania vonkajších ložiskových krúžkov vyrobených z nadeutektoidnej ocele 100Cr6. Meniaci sa parameter bola výška austenitizačnej teploty. Výsledky simulácie boli následne porovnané s výsledkami reálneho tepelného spracovania z hľadiska tvrdosti po kalení a fázového zloženia. Výsledky ukázali nepresnosti simulácie pravdepodobne spôsobené chýbajúcou fázou sekundárneho cementitu, ktorá má výrazný podiel na vlastnostiach reálnych krúžkov.

Thermal regime simulation with varying hardening temterature of three modes of oil quenching of ball bearing rings made of 100Cr6 steel was caried out in Sysweld program, based on finite element analysis. 3D model was prepared acording to manufacturing documentations of rough machined external rings. Hardening temperatures used 830, 850 and 870 degree celzius. As result complete graphical description of temperature, phase composition and hardness depending on time of quenching has been obtained. The results were compared with experimental heat treatment caried out with the same parameters. Comparison showed slight differences in hardness after quenching. In range of hardening temperatures applied, the observed microstructure consists of undisolved secondary cementite the volume fraction of which is depending on a number of parameters like heating speed, hardening temperature, holding time etc. This parameters have direct impact on microstructure and hardness after quenching. Sysweld software which was originaly created for simulation of welding of usual hypoeutectoid steels, is unable to predict secoundary cementite dissolution kinetics and therefore is not well suited for hardness and microstructure predictions for hypereutectoid steels in general. Nevertheless the time-temperature predictions and mechanical stress analysis can be very usefull for precise technological adjustments in industrial applications to prevent cracking or excessive deformation.

Kalenie, ložiskové krúžky, tepelné spracovanie

Quenching, heat treatment, ball bearing,

25.07.2014

Junior Euromat

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