Laser Surface Melting 

Laser surface melting is surface treatment process comparable to laser surface hardening. In laser surface melting heat input is however higher than in surface hardening so that objects surface is melted. Surface melting’s purpose is to improve materials surface qualities trough surfaces rapid melting and solidification. Such as like in laser surface hardening there is no additive in use.

In laser surface melting laser beam creates shallow melt pool rapidly. When laser beam is is moved towards material in front of melt pool melts and melt behind melt pool solidifies. Melt solidifies rapidly when melt exits laser beams area of influence. Heat is transferred from the melt zone elsewhere in the work piece, so additional cooling is not required.

Because of rapid solidification and cooling materials surface gets fine grained microstructure which composition is more homogenous than base materials. This increase for example stainless steels corrosion resistance. Also surface melting can increase cast iron parts wear resistance. If high laser power is used it is possible to reach very high process speed at which time solidification rate increase at very high level and surface can get cause of that amorphous form. Amorphous surfaces have better corrosion and wear resistance than crystalline structured surfaces.

Laser surface melting is used for example in automotive industry for melting camshaft surfaces for better wear resistance. Fine grained microstructure and compression stress which are achieved by this treatment improve camshafts wear and fatigue resistance.