SURFACE HARDENING OF OIL-HARDENED NONSHRINKING STEEL USING RUBY-LASER

Surface modification of metals and alloys using lasers has acquired co nsiderable importance because the changes achieved are highly localize d and superficial. In this process the mechanical and structural prope rties of the bulk are retained as such because of the high temperature gradient and high rate of change of temperature that are unattainable by conventional methods. The present report is on surface hardening o f oil-hardened nonshrinking (OHNS) steel using Ruby laser in normal mo de. It is found that surface hardening increases thrice the size of ba se material and the microstructure of the laser-heated zone changes fr om pearlite phase to martensite phase.