Atmospheric chloride-induced stress corrosion cracking of laser engraved type 316L stainless steel

The influence of aqua blasting and laser engraving on the atmospheric chloride-induced stress corrosion cracking (AISCC) resistance of type 316 L stainless steel has been elucidated by using MgCl2-laden droplet deposits as the test medium. Aqua blasted surfaces showed no evidence of AISCC. Laser engraving resulted in tensile residual stresses, and led to AISCC within two weeks of exposure, with crack growth rates similar to U-bend samples. Introducing compressive residual stresses via peening inhibited crack nucleation, whereas oxide layer removal of engraved surfaces had no effect on AISCC. Strategies to reduce the likelihood of AISCC of laser engraved components are discussed.