Cladding of WC–12 Co on low carbon steel using a pulsed Nd:YAG laser

Abstract

Laser cladding is an advanced material processing technology that has potential to deposit various materials locally on highly non-planar and complex surfaces. It can be used to refurbish or improve corrosion, wear and other surface related properties of components. The laser cladding of WC–Co using continuous wave (CW) laser has been tried and problems, like—cracks, porosity, poor bonding, partial melting of WC particles in the Co matrix, etc., have been observed. To resolve these issues, the successful laser cladding with alternate binder materials, like—Ni, Fe, Co–Cr, Ni–B–Si, etc., have been reported. In the present study, a pulsed Nd:YAG laser was used to deposit multi-layer overlapped cladding on low carbon steel substrate using dynamic powder blowing technique. Thus, produced laser cladding samples were subjected to various mechanical tests and metallurgical analyses. The results showed that fully dense and crack free clad surfaces of WC–Co with an excellent metallurgical bonding and low dilution were deposited. No melting of WC particles in the Co matrix was observed during the microscopy. The average microhardness at the clad surface was about 1350 HV, while that at substrate was 200 HV. The observed adhesion strength of the WC–Co cladding to the substrate was about 60 MPa.