Surface Modification of E690A Steel with Laser Cladded Ni60A Alloy Coatings

The surfaces of E690 steel, a widely used material for heating, ventilation and air conditioning(HVAC),was modified with the coatings deposited by laser cladding of Ni-based Ni60 A alloy powder.The influence of the laser power on the microstructures and tribological properties was investigated with X-ray diffraction and scanning electron microscopy and conventional mechanical probes.The preliminary results show that the laser power made the difference.Generally speaking, as the laser power increased, the thickness, hardness and wear resistance of the cladded layer increased, the grain-size and friction coefficient decreased, the uniformity and ductility improved.Cladded at 1300 W,the strengthening phases of CrNiC and CrFeNi formed in the 650 μm thick cladded layer, comprised the snowflake-like structures of the smallest eutectic grains.The formation of increasing SiC-density in molten spots brought about stronger interfacial adhesion, more solid solution strengthening and better ductility.