Abstract: The change of residual stress in surface layer of case-hardened 18Cr2Ni4WA steel during rolling contact fatigue is studied. Carburizing was carried out at 930℃ 4h, and then double quenching at 850℃ and tempering at 170℃ 2h were made . The hardness of case has HRC = 55 - 57 after grinding. The test condition was follows : the maxiumum hertzian strss was 2668MPa , rotational speed was 1470 r / min, lubrication was made using grade 30 machine oil, and the ratio of slide to roll was -5%. The strss was determined by x-ray analyzer after 0、 104、 105、 106、 107 cycle individually, and the residual austenite was determined by x-ray diffractometer. The results show that case-hardening treatment leads to compressive residual stress on surface layer of specimens . The change of residual stress in surface layer of specimens during the contact fatigue is limited and located within a definite zone. The transformation of residual austenite and decomposition of martensite are negligeable. The high structural stability of the carburized layer of 18Cr2Ni4WA is the main cause of the stability of residual stresses, which can be referred to for design.

Key words: contact fatigue, carburizing, residual stress