W18Cr4V高速钢激光相变强化的组织及性能

MICROSTRUCTURES AND PROPERTIES OF W18Cr4V HIGH-SPEED STEEL STRENGTHENED BY LASER

利用Ｘ射线、电镜、能谱和电子探针等对Ｗ１８ｃｒ４Ｖ高速钢激光相变强化的机理、组织、相组成及性能进行了研究，分析了碳化物在相变过程中的溶解机制和碳的扩散。激光相变强化后晶粒度由原来的８级提高到１２级；残余奥氏体（Ａ＿Ｒ）较常规淬火有明显减少，约１０～１５％；马氏体为针状和板条状混合组织。激光相变强化性能较常规热处理有很大提高：硬度达１０００ＨＶ０．１以上、红硬性提高８０℃，达６４０℃、耐磨性提高约５倍、韧性亦有显著改善。高速钢刀具经激光强化后寿命提高２～４倍。

This paper deals with study on phase transformation strengthening mechanism、structure and property of laser strengthened W18Cr4V high-speed steel.In this paper the laser phase transformation mechanism of the W18Cr4V steel was studied with X- ray、SEM、TEM、EDX and electronic probe. The solution mechan ism of the carbide and diffusion of carbon in the austenite at high temperature were discussed. The grain size has been refined from grade 8 to grade 12.The amount of retained austenite is about 10～15%in the phase transformation area and the martensite consists of both plate and lath structure. The properties of the laser strengthened layer have been improved much more than those commonly heat-treated,The hardness may be over 100 HV 0.1.Its wear resistance is 6～9 times that of Commonly heat-treated steel.The redhardness temperature of the laser strengthened layer can be increased by 8 0℃ and reached to 640 .The toughness is improved remarkably also.The life of laser strengthening ools is more han 2～4 times of that usually heat-treated .