Synthesising nanostructural wear-resistant coatings on martensite steel by welding methods

Abstract

A deposited material synthesised on steel Hardox 450 by flux cored wire Cr-V-Mo via the electric-arc method is studied in the paper on various scale levels of the structure. The results showed the mechanical properties (microhardness and wear resistance) were significantly improved compare to the base metal. After analysing the deflected mode of the deposited material in conditions of friction, the conclusion was drawn that plastic shear deformation is localised in the surface layer owing to the high friction factor, as the result, scratches are formed. The maximum of tangential stress is deflected deep into the material and provides low friction factor values. The results show that nanoscale secondary phases cause the decline of the friction factor, as their stress fields increase the resistance to shear. X-ray diffraction analysis allows detecting that these phases are iron oxides and carbides, and chromium carbide. The research based on transparent electron microscopy has shown that not only secondary phases but also the martensite structure of the matrix cause strengthening of the deposited material.