CAJ | 학술논문

采用冲击试验、X射线衍射分析、断口和显微组织观察，研究了回火温度和冷却速度对含硅型高铬马氏体耐热钢冲击韧性的影响。研究结果表明，含硅型高铬马氏体耐热钢在400℃以下回火时组织中存在少量残余奥氏体，在450～600℃区间存在高温回火脆性，硬度达到峰值，产生沿晶和准解理混合断裂。分析认为，沿晶界生成的链状碳化物降低晶界结合强度，以及基体组织中析出的大量细小弥散的碳化物产生二次硬化，两者是回火脆性产生的主要原因。冷却速度通过碳化物析出差异影响基体强度，进而影响钢的冲击韧性。
채용충격시험、X사선연사분석、단구화현미조직관찰，연구료회화온도화냉각속도대함규형고락마씨체내열강충격인성적영향。연구결과표명，함규형고락마씨체내열강재400℃이하회화시조직중존재소량잔여오씨체，재450～600℃구간존재고온회화취성，경도체도봉치，산생연정화준해리혼합단렬。분석인위，연정계생성적련상탄화물강저정계결합강도，이급기체조직중석출적대량세소미산적탄화물산생이차경화，량자시회화취성산생적주요원인。냉각속도통과탄화물석출차이영향기체강도，진이영향강적충격인성。
The effects of temper temperature and cooling rate on the impact toughness of a silicon-bearing high chromium martensitic heat resistant steel were studied by a series of Charpy impact test ,X-ray diffraction and fracture morphology and microstructure observations .T he results show that the retained austenite exists in the microstructure of the steel tempered below 400 ℃ ,the toughness of the steel decreases greatly when tempered at 450-600 ℃ and the Vicker hardness reaches a maximum ,where the steel exhibites a morphology of intergranular plus quasiclevage fractures .The grain boundary weakening caused by the precipitation of chain-like carbides along grain boundaries and the secondary hardening produced by fine dispersed carbides are considered to be the main causes for the temper embrittlement .The strength of the steel matrix decided by the difference in carbides precipitation due to the different cooling rates show s significant effect on the impact toughness of the steel .