激光熔覆工艺参数对Fe-Cr-B合金涂层组织和硬度的影响

Effect of processing parameters on microstructure and hardness of Fe-Cr-B alloy coating by laser cladding

利用6 kW光纤激光器在Cr12MoV模具钢表面激光熔覆Fe-Cr-B合金涂层。运用金相显微镜和显微硬度仪,研究了激光功率、扫描速度、送粉率对熔覆层成形、尺寸、稀释率及组织结构和微观硬度的影响。结果表明:熔覆层组织主要由平面晶、树枝晶和等轴晶构成。理想的工艺参数为激光功率(P)2000 W,扫描速度(V1)4 mm/s,送粉率(V2)15 g/min。该工艺参数下熔覆层晶粒细小,与基体呈现良好冶金结合,稀释率为9.8%,熔覆层显微硬度平均高达1000 HV。

Laser clad Fe-Cr-B alloy coating was fabricated on the surface of Crl2MoV mold steel by using a 6 kW fiber laser. The effects of laser power, scanning velocity, powder feeding rate on the formability, size, dilution rate, microstructure and microhardness of the cladding layer were researched by means of metallographic microscope and microhardness tester. The results show that the microstructure of the cladding layer is composed mainly of plane crystal, dendrites and equiaxial grains. The proper laser cladding parameters determined based on the experiment, which are as follows ： P （ laser power） = 2000 W, V1 （ scanning speed） -- 4 ram/s, V2 （ powder feed rate） = 15 g/ min. Under the laser cladding paramete.rs, the fine gains are obtained, the dilution rate is 9.8% and the highest microhardness of the cladding layer exceeds 1000 HV.