Studies on laser bending of stainless steel

Abstract

In the present study, laser bending of AISI 304 stainless steel sheet has been attempted with a high power (2 kW) continuous wave CO₂ laser. Bending angle was measured as a function of laser/processing parameters including power density, scan speed, number of passes and sheet thickness. Following laser bending, microstructural evolution (using a scanning electron microscope) and phase analysis (by X-ray diffraction technique) were systematically carried out to study the effect of laser irradiation and thermal stress on the microstructure and phase transformation behavior of the sheet. Microhardness of the bent sheet at different position was carefully measured using a Vickers microhardness tester. Bending angle was found to vary from 0.5° to 70° under different processing conditions. The microhardness of the bend zone was found to increase (from 1.5 to 2 times) as compared to the as-received sample. The improved microhardness is attributed to grain refinement associated with rapid quenching during laser bending. Finally, the optimum processing zone for laser bending of stainless steel was derived.