Study Of Fe-C-Cr-W Composite Coating On Q235Steel By TIG Cladding

As is well known, wear and corrosion are mechanical parts’ main forms of failure inengineering application. Especially, with the development of modern industry, a largenumber of engineering parts are in complex and bad environment. Materials’ failure causedby wear and corrosion has brought huge economic losses. In order to improve theperformance and solve the problem of wear and corrosion on the surface of the material, Imade three kinds of cladding layers on the surface of Q235steel by TIG cladding, whichwas simple and cost less. The results obtained are of practical value.Through changing the cladding current, precoating thickness, cladding speed and argonflow, I analyzed macro shape, microstructures and the influence rule of microhardness.Results showed that the best process parameters were as follows. Cladding current,precoating thickness, cladding speed and argon flow respectively were120A,1.2mm,9cm/min and8L/min.I analyzed the microstructures of cladding layers with different contents by means ofphase analysis (XRD) and microstructures observation (SEM). The results showed that theinterface were metallurgical combination and flat crystal grain morphology transited tocellular crystal and dendrites from the interface to cladding layer. I designed proportion ofpowders according to the carbides forming. Consequently, the in-situ synthesis reactionreacted and generated carbides as reinforced phases. With the increase of (C-Cr-W) or (C-W)powders, the number of carbides obtained by in-situ synthesis increased as well.Under the condition of optimum cladding technology, the best microhardness value isabout1300HV, which is up to6times of Q235steel substrate. At the same time, claddinglayers’ wear and corrosion property has increased greatly compared to the matrix. Resultsshow that the minimum wear loss is only1/4of the matrix. Main wear mechanism isabrasive wear, adhesive wear and oxidation wear. The minimum corrosion loss is only1/11of the matrix. In a word, the cladding layer with contents of (C-Cr-W) or (C-W) powders70percent shows the best comprehensive performance.