Chromium alloyed steel nitriding within close-to-critical temperature range

The paper presents X-ray diffraction and scanning electron microscope analyses, and durometer measurements used to investigate the structural properties and phase composition of nitride layers of type 20Kh13 mild steel. A method of nitriding by low-pressure arc discharge was applied along with the combined surface treatment including ultrasonic finishing and nitriding. It was shown that within the close-to-critical temperature range starting from 200ºС, the nitride layers was formed on the surface of type 20Kh13 mild steel. The ultrasonic pre-treatment shown its effect on the steel nitriding that increased the amount of nitride phases and the value of microharness on the steel surface.