Effect of Nb on Microstructure and Properties of Laser Cladding Fe-based Coating on EA4T Steel Surface
In this paper,the effects of different Nb contents on the microstructure and mechanical properties of the cladding layer were studied by laser cladding Fe-Cr-Ni-Nb powder on the surface of EA4T axle steel.The microstructure of the clad-ding layer was analyzed by optical microscope(OM)and scanning electron microscope(SEM).The hardness and impact toughness of the cladding layer were tested by microhardness tester and impact test.The results show that the cladding layer with different Nb content is mainly composed of austenite,FeNi solid solution and(Cr,Fe)7C3.With the increase of Nb con-tent,the grain size of the cladding layer is refined.However,compared with the cladding layer without Nb,when the Nb ele-ment is added,the tensile strength and yield strength of the cladding layer are significantly improved.The average tensile strength increases by 42.5%,37.7%and 13.1%,respectively,and the average yield strength increases by 26.5%,18.9%and 14.1%,respectively.In addition,the impact toughness of the cladding layer is also improved with the increase of Nb content.Compared with the cladding sample without Nb,the average impact energy is increased by 8.3%,9.4%and 26.4%,respec-tively.On the whole,the cladding layer with Nb content of 0.9%has the best comprehensive mechanical properties.
laser claddingNb element contentmicrostructuresmechanical properties
万方数据
维普
