The effect of 316 steel surface roughness on absorption of 1064 nm laser emissions

The dynamic realm of laser absorption in materials is not yet fully understood because the amount of energy absorbed by metal surfaces is not well characterized. Previous studies of the absorptivity of metals during industrial laser welding have indicated some dependence on surface roughness and plume obstruction. No prior experimental data exist for commercially available stainless steel 316 (316SS). This work presents a new dataset of the effective absorptivity of 316SS as a function of pulse width and surface roughness at 108 W using calorimetry. Experimental data indicate that 316SS with a surface roughness greater than half of the wavelength of the laser—1064 nm in this study—absorbs more energy. The effective absorptivity at laser pulses longer than 3 ms has a low confidence due to obfuscation of the laser after plume formation.