Analyzing the effect of the parameters of laser etching process influencing the corrosion resistance and surface roughness of marine grade 316 stainless steel

Abstract

Laser etching process is used for marking those materials which cannot be marked by conventional machining processes. The aim of the current study attempts to investigate the effects of Laser etching parameters specially the scanning speed [ns], peak power [kW], frequency [kHz] and heat input [J/mm2] on the corrosion resistance and variations in surface roughness properties of the Marine grade 316 Stainless Steel. In the laser etching process the surface of the material is incident by a laser beam which heats up the marked area and subsequently vaporizes the material leading to formation of oxide layer on the surface, which when comes in contact with aggressive environment causes a chemical reaction on the bare steel leading to corrosion. The experiment was performed after marking on the material surface body with Nd: YAG Solid State UV Laser beam using Laser annealing process. Surface roughness is an important parameter that affects the tribological behavior of surfaces. In the food processing industry the '316′ grades are unofficially known as the 'food' grades because the lower the surface roughness, the better, since corrosive material and bacteria are less likely to stick to a very smooth surface. The samples were subjected to salt spray test to check corrosion resistance of materials. Taguchi method of orthogonal array based on Minitab 18 was used to determine the best factor level condition. Marking quality was evaluated by visual examination. Analysis of variance (ANOVA) has been applied on experimental data to identify the relative significance of process parameters on the response. The analysis shows that the laser beam scanning speed is the most influential operating factor.