车轮铸钢材料热循环表面氧化特征分析

Study on Thermal Fatigue Surface Damage Behaviours of Wheel Cast Steel

研究了车轮铸钢在不同温度幅下热疲劳损伤表面及次表层行为．研究发现，表面氧化及剥落现象和氧化物的开裂随循环上限温度的增高而愈加严重；次表层损伤以裂纹为主，附带一些蚀坑．其损伤机理是由于氧化脱碳使铁素体区形成腐蚀坑，腐蚀坑的连接形成微裂纹，热疲劳主裂纹优先通过铁素体区氧化腐蚀坑而向前扩展．

The thermal fatigue damage behaviours of the surface and subsurface under different temperature amplitudes have been studied. Results show that oxidation detaching and cracking induced by oxidation become more serious with cycling maximum temperature increasing. Damage of the subsurface is in the main form of cracking with some etching pits. Thermal fatigue damage mechanisms are that etching pits firstly formed in the ferrite area due to oxidation decarbonization, and then the pits were linked up each other so that microcracks formed. The principal crack has a priority to propagating through etching pits in ferrite area.