刀具用W18Cr4V钢表面激光熔覆CoMoN/WC涂层组织与红硬性分析  

Red Hardness of Laser Cladded CoMoN/WC Composite Coating on W18Cr4V High Speed Steel

作　　者：程改兰 冯金广[2] 陈正学 Cheng Gailan;Feng Jinguang;Chen Zhengxue(School of Mechanical and Electrical Engineering,Zhengzhou Vocational College of Information Technology,Zhengzhou 450008,China;School of Mechanical and Electrical Engineering,Henan Vocational and Technical College,Zhengzhou 450008,China;Henan Mechanical Design and Research Institute Co.,LTD.,Zhengzhou 450008,China)

机构地区：[1]郑州信息科技职业学院机电工程学院,郑州450008 [2]河南职业技术学院机电工程学院,郑州450008 [3]河南省机械设计研究院有限公司,郑州450008

出　　处：《真空科学与技术学报》2020年第5期432-436,共5页Chinese Journal of Vacuum Science and Technology

摘　　要：选择W18Cr4V高速钢刀具作为测试基体,综合运用淬火与回火相结合的工艺处理基体。在其表面激光熔覆一层高硬度的CoMoN/WC涂层,实验测试分析各个回火温度得到的涂层硬度及其微观组织。研究结果表明:1)CoMoN/WC涂层跟基材达到了异冶金结合状态,在涂层内存Fe3W3C硬质相组织以及各类间隙态的化合物,使涂层获得很高的硬度。位于涂层中上区域存在大量的树枝晶与部分等轴晶,在中部区域形成了许多大尺寸树枝晶,在涂层底部存在许多小孔以及许多大尺寸的黑色组织。涂层形成了梯度硬度分布状态,相对于基体发生了硬度的大幅提升。三次回火+淬火循环处理涂层获得更高硬度;当回火温度上升后,涂层的硬度表现为不断减小。对试样进行高温处理后会引起晶粒的长大现象,同时减弱了组织细化的效果,形成了更多的位错数量。The CoMoN/WC composite coatings,synthesized by laser cladding of a layer of CoMoN/WC powders pre-coated on W18 Cr4 V high-speed steel substrate,were modified by quenching/tempering cycles.The influence of the tempering temperature and quenching-tempering cycle number on the microstructures,hardness and red hardness of the CoMoN/WC coatings were investigated.The preliminary results show that the tempering temperature had a major impact.To be specific,the tissue refinement,formation of Fe3W3C and interstitial compounds significantly increased the hardness of the coatings.As the tempering temperature increased(in three cycles),the hardness decreased,because high temperature increased grain-size and dislocation density.Formation of hetero-metallurgical bonding enhanced interfacial adhesion.The fact that many dendrites and some equiaxed-grains occupied the top,larger dendrites controlled the middle,and high density of pores and large black clusters dominated the bottom explains the depth profile of hardness.

关 键 词：激光熔覆 CoMoN/WC粉末 显微组织 硬度 

分 类 号：TG174[金属学及工艺—金属表面处理]