Abstract: In view of the surface modification of shearer picks, effect of B₄C addition (3%, 5% and 7%) on the cross-section morphology, microhardness, wear resistance and corrosion resistance of the Stellite6+B₄C laser clad layers on 42CrMo steel was studied by means of X-ray diffractometer, scanning electron microscope, Vickers microhardness tester, multifunctional friction and wear testing machine and electrochemical workstation. The results show that the cross-section morphology of the clad layer is good when the B₄C addition is 3% and 5%, however, when the B₄C addition is 7%, there are many defects on the surface of the clad layer. With the increase of B₄C addition, the microhardness of the clad layer increases from 781.04 HV to 1044.72 HV, the average friction coefficient decreases and the wear loss decreases first and then increases. When the B₄C addition is 7%, the average friction coefficient of the clad layer is 0.42, but due to the poor forming quality, the wear loss is the highest as 1.9 mg. When the B₄C addition is 5%, the wear loss is the least as 0.6 mg. The corrosion resistance of the clad layer first increases and then decreases with the increase of B₄C addition. When the B₄C addition is 5%, the self-corrosion potential of the clad layer is the highest, the self-corrosion current density is the smallest, and the charge transfer resistance R_ct is the largest, the best corrosion resistance of the clad layer is obtained.

Key words: shearer pick, laser cladding, Stellite6+B₄C clad layer, wear resistance, corrosion resistance