Study On Induction Cladding Process Of WC Particle Reinforced Ni Based Self Melted Alloy Gradient Coating

In this paper,the gradient coating of WC particle reinforced Ni based self melted alloy was prepared on the surface of the precipitation hardening martensitic stainless steel with 19 x 55 mm by the composite process of oxygen acetylene flame spraying and induction cladding.The surface roughness of the cladding layer was measured by the surface profilometer,the cross section morphology and the interface state of the cladding layer were observed by scanning electron microscope,and the porosity of the cladding layer was calculated by using the image processing software and the data statistics software,and the hardness distribution of the cladding layer and the matrix and the softening depth of the matrix were measured by microhardness tester.The diffusion of elements to the matrix was observed by metallographic microscope,and the impact test was carried out by the fatigue hydraulic servo fatigue testing machine for the hard alloy coating with the gradient interface layer.The results of the study show that:(1)The high frequency induction cladding(frequency is 20 kHz)for Ni60 A coating prepared by flame spraying.With the increase of current,the porosity of the cladding layer decreases and the output current is 800 A,the interface is converted to metallurgical bonding,the porosity is 0.45%,the surface roughness Ra value is 1 ?m,the Heat affected zone depth is about 70 ?m;the flame spraying is prepared.The Ni60A+Ni60-40 WC coating has high frequency induction cladding.The metallurgical bonding state of the interface is good when the output current is 840 A.The porosity of the cladding layer of the Ni60-40 WC cladding layer is 0.56%,the porosity of the cladding layer is 0.87%,the porosity of the Ni60 A cladding layer is 0.86%,the porosity of the cladding layer and the matrix is 1.12%,and the surface roughness Ra value is 0.9.The Heat affected zone depth is about 70 ?m.(2)UHF induction cladding(frequency 250 kHz)for Ni60 A coating prepared by flame spraying,the porosity is 0.45%,the surface roughness Ra value is 1 micron m,and the softening depth of the matrix is about 30 ?m when the output current is 400 A,and the output of the Ni60A+Ni60-40 WC coating by flame spraying is produced by UHF induction cladding.When the current is 410 A,the porosity of the Ni60-40 WC cladding layer is 0.56%,the porosity of the cladding interface is 0.87%,the porosity of the Ni60 A cladding layer is 0.86%,the porosity of the interface layer of the cladding layer and the matrix is 1.12%,the surface roughness Ra value is 0.9 mu m,and the softening depth of the matrix is about 30 ?m.(3)The hardness of the coating with the interface layer varies from the matrix to the outer coating,and the hardness layer of the coating changes to the better branch of the coating.Support.In the same external impact environment,the height of the coating with the interface layer is about 2 ?m,while the coating without interface layer has a deformation of 6 ?m.