이중 퀜칭 열처리 공정을 이용한 베어링강의 입자미세화에 관한 연구 = A study on grain refinement of bearing steels using double quenching heat treatment

다국어 초록 (Multilingual Abstract)

It's known that high carbon bearing steels with fine grain size are superior in fatigue properties than conventional high carbon bearing steels. In this investigation, double quenching process was proposed to improve fatigue life by grain refinement of high carbon bearing steel. Microstructures were investigated by means of optical microscope, within JIS-SUJ2(SAE 52100) bearing steel we have produced a prior-austenite grain size of approximately up to 5 ㎛ in diameter. Secondary quenching temperatures and holding time were 780℃, 800℃, 820℃, 20min, 40min, 60min, and we performed for each condition to optimize heat treatment cycles. Secondary quenching temperatures can be lower than conventional austenizing temperature, because nitrocarbonized bearing steels through first quenching process have lowered A1 temperature and grain refinement need low austenizing temperature. Bearing steels used in field need to satisfy required hardness as well as fine microstructures.

목차 (Table of Contents)

• Abstract
• 1. 서론
• 2. Experimental Procedure
• 3. 결과 및 고찰
• 4. 결론
• References