Effect of Laser Scanning Rate on Characteristics of Biphasic Stainless Steel Coatings

Abstract

Laser cladding is a facile and inexpensive method for coating a layer of duplex stainless steel on steel substrates. In this study, a thick coating (200 mu m) of Fe42Cr20Mo16Ni12C10 alloy powders was successfully bonded to a 316L stainless steel substrate through laser cladding. Various laser scanning speeds (4, 6, 8 mm/s) were employed to achieve the desired results. The coating consisted of ferrite and austenite with no undesired phase such as sigma (sigma) or chi (chi). Notably, the sample synthesized at a laser scanning rate of 6 mm/s exhibited equal amounts of ferrite and austenite phases (approximately 50 ferrite-50 austenite) with the same weighting rate of elements in each phase. Additionally, this sample demonstrated the lowest porosity around 0.8. As a result, the coating showed superior pitting corrosion resistance compared to others. This study holds potential for the future development of highly practical duplex stainless steel coatings with enhanced corrosion behavior.