Analysis of microstructure and wear performance of SiC clad layer on SKD61 die steel after gas tungsten arc welding

In this research, the metastable phases, such as Fe3C and Fe8Si2C, were synthesized in situ during a cladding process with gas tungsten arc welding (GTAW), which used silicon carbide (SiC) powder to clad on an SKD61 die steel substrate. According to the nanoindentation test and microstructure observation, these metastable phases displayed hard and complex geometric structures in the SiC clad layer. Moreover, because the SiC clad layer contained a large amount of Si and C elements, it was easy to promote graphite precipitation during solidification. During sliding, the hard and complex microstructure in the SiC clad layer caused the mechanical interlocking effect, so that the worn surface would be difficult to result in the serious adhesion and plastic deformation. Furthermore, because the graphite distributed over the worn surfaces, it could provide good lubricity. Under the dry sliding wear test, the wear performance of an SKD61 die steel specimen with the SiC clad layer was much better than that of an SKD61 die steel specimen, and even better than that of an SKD61 die steel specimen with the WC clad layer.