Electron-Beam Modification of Carbon Steel Surface

Abstract

Mechanisms of hardening the carbon steel 45 surface after combined treatment have been elucidated. Combined treatment inclucdes electroexplosive boroaluminizing or aluminizing in the presence of silicon carbide and subsequent electron-beam processing. It has been found that the microhardness increases by seven and sic times and the wear resistance improves by 2.5 and 1.7 times, respectively. Under the conditions of dry sliding friction, the wear resistance after electroexplosive boroaluminizing and electron-beam processing increases by 43 times and after electroexplosive aluminizing in the presence of silicon carbide it rises by 12 times. It has been shown that after the combined treatment, a multiphase structure forms in the steel 45 alloying zone. This zone consists of martensite packets and lamellas; retained austenite interlayers; ferrite grains and subgrains; austenite cells; submicrometer SiC particles and Al₄SiC₄ nanoparticles; and AlB₁₂, AlFe₄, and Fe₃Si second-phase precipitates. Surface hardening is dude to the formation of a fine-grained nonequilibrium structure containing hardening phases. Electron-beam irradiation smoothes the surface relied, “heals” microcracks, and improves functional properties.