Evaluation of the effect of process parameters on the cut quality in fiber laser cutting of duplex stainless steel using response surface method (RSM)

Abstract

Fiber laser cutting of stainless steel material is known as one of the most efficient cutting methods, with an acceptable quality and low production costs. Duplex stainless steels have higher chromium and molybdenum contents, making their thermophysical properties different in comparison to austenitic stainless steels; this can have a direct impact on the cut quality in the laser cutting process. In this research, the effect of such process parameters as cutting speed, focal length and laser power on the temperature adjacent to the cut kerf and cutting surface roughness was systematically investigated through the response surface methodology (RSM). The central composite design (CCD) was also used for the experimental design and analysis of variance (ANOVA), showing the effect of the participation of each factor on the responses. The laser power had the most significant influence on the temperature around the cut kerf by increasing the temperature from 180 to 500 °C, with the increase of the laser power from 700 to 1100 W. Increasing laser power continuously diminished the surface roughness about 45 percent. The minimum surface roughness value was recorded at the focal length of 0.4 mm, at which the laser energy density was at the highest level of 5100 W/mm2. Increasing the laser power up to 900 W, clearly improved the roughness although increasing power up to 1100 W has had a detrimental effect the surface roughness which was led to the creating some cavities and dross at the cutting surface.