Surface Boriding and Titanization Stainless Steel by Integrated Processes

The phase and element composition, defect sub-structure in the surface layer of stainless high-chromium steel 12Cr18Ni10Ti (0.12% C, 1.8% Cr, 10% Ni, 1% Ti) alloyed in the electric explosion have been investigated in an X-ray analysis and with the help of optical, scanning and transmission electron microscopy in the diffraction mode. Titanium and boron have been selected as alloying elements. Once a steel surface modified via the electrical explosion alloying is irradiated by an intensive pulsed electron beam, a multi-phase sub-micro nano-crystalline surface layer (up to 60 mu m) with no micro-pores and micro-craters is produced. The research has demonstrated two-element compounds only form in the modified layer of steel. The microhardness of a modified layer is related to a part of titanium borides in the surface of steel, being more than 18 times higher after the electrical explosion alloying than in as delivered state. As a result of the subsequent irradiation by an electron beam, a surface layer is formed in the steel alloyed via the electrical explosion; the microhardness and wear resistance of this layer are seven and nine times, respectively, higher than these parameters in as delivered state.