Mechanical and electrochemical properties of multiple-layer diode laser cladding of 316L stainless steel

In the present investigation, a detailed mechanical and electrochemical properties of multiple-layer laser clad 316L stainless steel (from the powders produced by gas atomized route) has been carried out. Multiple-layer laser cladding of 316 L stainless steel has been conducted using a diode laser. The mechanical property (microhardness) of the fabricated product has been evaluated using a microhardness testing machine and correlated with the process parameters. The electrochemical property, mainly pitting corrosion resistance of the fabricated layer corresponding to maximum microhardness (in a 3.56% NaCl solution) has been evaluated using standard potentiodynamic polarization testing. The microhardness of the laser assisted fabricated layers was found to vary from 170 to 278 VHN, increased with decrease in applied power density and increase in scan speed and was higher than that of conventionally processed 316L (155 VHN). The superior microhardness value is attributed to grain refinement associated with laser melting and rapid solidification. The critical potential to pit formation (EPP1) was measured to be 550 mV saturated calomel electrode (SCE) and superior to the conventionally processed 316L stainless steel (445 mV (SCE))