Laser surface pretreatment of stainless steel

Laser surface remelting and solidification, as one of the advanced surface modification methods, is being widely used in industry. However, most machined workpieces are bright, which causes most of the laser energy reflect away from the surface. So a kind of surface pretreatment (or blacking treatment) must be done in order to increase the energy absorptivity. A new pretreatment method for the stainless steel has been developed. The method is to put the workpieces into the dichromic (DCR) salt melt and keep a certain time. The experimental results show that the DCR method can greatly improve the absorptivity of the workpieces and do not contaminate it. Furthermore, the method is handy and inexpensive.