扫描速度对40Cr表面等离子束硬化层组织和性能的影响
Influence of Scanning Speed on Plasma Beam hardening Microstructure and Property of 40Cr
张占哲，李刚
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作者单位：华北水利水电学院机械学院
中文关键字：等离子束；硬化层；硬度；耐磨性
英文关键字：plasma-beam; hardened layer; hardness; wear resistance
中文摘要：采用等离子束热源对40Cr表面进行硬化处理。利用扫描电子显微镜和金相显微镜分析了硬化层的显微组织结构,并对硬化层进行显微硬度和耐磨性测试。结果表明：硬化区整体形貌呈月牙形，熔凝区组织形态为隐针马氏体+网状索氏体+残余奥氏体，相变淬火区组织为隐针马氏体+网状屈氏体+残余奥氏体+铁素体；其他工艺参数不变， 随着扫描速度的增大，硬化层深度和宽度减小，而最高硬度值增加；沿硬化层层深的硬度分布规律是，从硬化层由表及里显微硬度先升高后降低，最高硬度在次表层；沿硬化层层宽的硬度分布规律是，硬化层中心部位硬度略有降低，向两侧硬度值先升高后降低，直至40Cr基体硬度值。硬化处理后试样耐磨性显著提高。
英文摘要： The surface of 40Cr was hardened by plasma-beam. Use scanning electron microscopy and metallurgical microscope analysis of the hardened layer microstructure. And the hardness and wear resistance of hardened layer was tested. The results show that:The overall morphology of hardened zone Showed a crescent-shaped.In remelt-solidified region the microstructure is martensite, sorbite and austenite. 1n transformation hardening region is martensite,troostite, austenite and ferrite. Along with the scanning speed increasing, the width and depth of hardened layer diminishes，and maximum hardness increases．From the surface to inner, the micro-hardness changing tendency is firstly going up then going down and the highest hardness point is in second-surface layer.with the hardening layer upon layer width, the hardness of hardened layer center is decreased slightly, the hardness value firstly going up then going down to two sides, until the 40Cr substrate achieves the minimum value.The wear resistance of harden layer improved significantly.