Abstract: This paper deals with the microstructure and the wear resistance of 45-steel after laser transformation hardening.The experimental results show that the hardened zone is composed of three layers:the hardened layer,the partially hardened layer,the transition layer.The hardened layer consists of fine martensites.The partially hardened layer consists of fine martensites and a few bainites.The transition layer consists of martensites and a few carbide-free bainites and some undissociated ferrites.The hardened zone has better plastic deformation resistance and adhesive wear resistance properties that come from the contribution of martensite to strength and hardness of the hardened zone,and the contribution of residual austenite and bainite to toughening of the hardened znoe.

Key words: carbon steel, laser transformtaion hardening, microstructure, wear resistance property

摘要： 本文研究了45钢激光相变硬化后的显微组织及耐磨性能。研究结果表明:45钢激光相变硬化后硬化带由完全淬火区、部分淬火区和过渡区组成。完全淬火区为极细针状马氏体+板条马氏体混合组织;部分淬火区为细马氏体(已部分自回火)+少量贝氏体组织;过渡区为马氏体+少量无碳化物贝氏体+部分未溶铁素体组织。硬化带具有较强的抗塑性变形和抗粘着磨损能力。45钢激光相变硬化带的优异耐磨性能来源于超细马氏体对硬化带强度、硬度的贡献;残余奥氏体和贝氏体对硬化带韧性的贡献。

关键词: 碳钢, 激光相变硬化, 显微组织, 耐磨性