扫描速度对中锰铁基合金激光熔覆层组织和性能的影响

Effect of Scanning Speed on Microstructure and Properties of Medium Manganese Fe-based Alloy Laser Cladding Layer

利用激光熔覆技术在42CrMo钢表面制备了中锰铁基合金熔覆层。采用OM、SEM、XRD、显微硬度仪及SRV4摩擦磨损试验机对不同扫描速度下熔覆层的组织及性能进行了研究。结果表明:熔覆层与基体呈冶金结合,熔覆层均由熔覆区、热影响区和基体三部分组成,其组织由下至上依次为平面晶、树枝晶和胞状晶,且随扫描速度的增大,组织细化。熔覆层组织由马氏体和奥氏体组成,且随着扫描速度的增大,马氏体含量略有增加。熔覆层的显微硬度随着扫描速度的增加呈减小的趋势,在5 mm/s时硬度达到最大的739 HV0.1。熔覆层的耐磨性好于基体,但随扫描速度的增大而变差,5 mm/s时耐磨性最好,相对磨损性是基体的2.57倍。

The medium manganese Fe-based alloy cladding layers were fabricated on 42CrMo steel surface by using laser cladding technology.The microstructure and mechanical properties of the cladding layer under different scanning speeds were analyzed by OM,SEM,XRD,scanning electron microscope(SEM),microhardness tester and SRV4 friction wear testing machine.The results show that the cladding layer and matrix is metallurgical bonding.The cladding layer is divided into three parts:cladding zone,HAZ and substrate.The microstructure of the cladding layer from bottom to the top is planar crystal,dendrite crystal and cellular crystal,and the grain is refined along with the scanning speed increasing.The microstructure of the cladding layer consists of martensite and austenite,and the martensite content increases slightly with the scanning speed increasing.The microhardness of the cladding layer decreases while the scanning speed increases,when the scanning speed is 5 mm/s,the microhardness is up to 739 HV0.1.The abrasion performance of the cladding layer is better than that of the matrix,but it decreases with the scanning speed increasing,when the scaning speed is 5 mm/s,the relative wear resistance is2.57 times of the substrate.