40CrNiMoA齿轮激光表面强化及抗疲劳性分析

对40CrNiMo齿轮进行了激光表面强化处理,用SEM和TEM对处理试样显微组织进行了分析,测试并分析了其显微硬度,并进行了抗疲劳性现场试验,结果表明:40CrNiMo激光淬火后其组织由淬硬层、过渡区和基体组成,淬硬层组织为细小的板条马氏体和针状马氏体,层深约1.5mm,过渡区为马氏体和索氏体混合组织,基体为回火索氏体。淬硬层表面硬度比常规淬火硬度有所提高。40CrNiMo激光淬火齿轮比20Cr2Ni4渗碳淬火齿轮疲劳强度提高约10%。

Laser surface hardening and fatigue resistance ability analysis of 40CrNiMoA gear

40CrNiMoA gear was surface hardened by laser. Microstructure of sample was analysized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). And microhardness was studied. The fatigue resistance was tested in situ. It was shown that laser hardened layer consists of hardening layer, heat affect zone ( H AZ) and substrate after laser hardening. The microstructure of hardening layer contains fine plate mar-tensite and needle martensite. The thickness of layer is about 1. 5mm. HAZ composites martensite and ultrafine pearlite in mixture. Substrate is tempered ultrafine pearlite. Surface hardness of hardening layer was improved compared with conventional hardening. Fatigue strength of 40CrNiMo gear by laser hardening was increased by 10% compared with that of 20Cr2Ni4 carbonized.