Experimental Research on Microstructure and Properties of a 9%Ni-Fe Alloy Laser Cladding Coating

In order to improve the hardness and heat resistance stability of H13 steel surface,a 9% Ni-Fe alloy coating was prepared on the surface of H13 steel by laser cladding technology.Microstructure,phase composition,and micro-hardness of the alloy coating and thermal stability was investigated by X-ray diffraction（XRD）,metallographic microscope,scanning electron microscope（SEM）,energy spectrometer（EDS）,micro-hardness tester and other experimental instruments.The results show that the cladding layer is well bonded to the substrate without presence of defects such as cracks and pores. From the cladding layer to the matrix,the solidified structures arechanging from equiaxed,dendritic,columnar to cellular.The coating phase is mainly composed of α-Fe and some intermetallic compound reinforcing phases,and its content is beyond XRD detection. The micro-hardness of the coating after cladding has reached 1.5 to 2 times of the matrix structure,and the increase in hardness has significantly strengthened the matrix. The coating has good thermal stability and is the most stable at 400 ℃ .The Fe-based alloy coating can significantly improve the hardness and thermal stability of H13 steel and extend its service life.