Organization and properties of the surface bionic gradient hardness high strength layer of 17-4PH stainless steel

In this paper, it is proposed to prepare a high hardness wear-resistant layer on the surface of 17-4PH stainless steel, and in order to alleviate the problem of cracking between the high hardness cladding layer and the substrate, it is proposed to prepare a bionic gradient hardness surface cladding structure. The use of manual electric arc welding in the 17-4PH stainless steel surface preparation of bionic gradient hardness high strength layer, the choice of D322 electrode and D707 electrode were used as a transition layer and high strength layer in the 17-4PH stainless steel surface for the preparation of the bionic gradient hardness high strength layer, the use of optical microscopy, Vickers hardness tester, X-ray diffractometer, impact testing machine on the high strength layer of the microstructure, microhardness and other properties were characterization. The results show that the bionic gradient hardness high-strength layer prepared on the surface of 17-4PH stainless steel has a uniform organization and good interfacial metallurgical bonding. The organization of the bionic gradient hardness high-strength layer mainly consists of martensite, austenite, WC and carbide. The bionic gradient hardness high-strength layer phase structure mainly consists of Fe-Cr, WC, γ-Fe, with an average hardness of HV_0.5 726.5, which is a significant improvement compared with that of the substrate. The bionic gradient hardness high-strength layer on the surface of 17-4PH stainless steel is also a good example of a bionic gradient hardness layer. 17-4PH stainless steel surface bionic gradient hardness high-strength layer average impact absorption power is 12.90 J, the main reason for the reduction of its impact absorption power is due to the different properties between the layers.