Abstract: KMN steel is a kind of high-strength low alloy steel which commonly used in large centrifugal compressor impeller. It is often failed in service process caused by wear, corrosion and other damage. Laser cladding is an effective means to remanufacture of failure impeller. Based on this, the FeCr alloy is deposited on KMN steel plate which had been preset defect by laser cladding. The microstructure, phase constitution, hardness and wear resistance of the clad layer are investigated by scanning electron microscope (SEM), energy dispersive spectroscopy(EDS), X-ray diffractometer, Vickers digital micro-hardness tester, sliding wear tester and optical profiler. The Tafel curves of repaired layer and KMN substrate are measured. The etching rate is analyzed for both of them. The results show that the recovered layer is free of cracks and has a good metallurgical bonding with substrate. The laser cladding repaired coating present a great hardness, excellent wear resistance and corrosion resistance.

Key words: corrosion resistance, impeller remanufacture, KMN steel, laser cladding, wear resistance