Effect of Laser Marking on Corrosion Performance of Metallic Materials in Different Environments

摘要

This study was undertaken as an effort to understand the effect of laser marking on corrosion behavior of metallic materials. Two laser-marking companies and two metallic materials low alloy steel AISI 4140 (UNS G41400) and stainless steel AISI 420M (UNS S42000) were selected for this study. The obtained results indicate that the laser marking process created a thin black oxide layer on the metal surfaces without significantly affecting the base materials. In term of corrosion performance, the obtained results suggest that the laser marking does not have a significant effect on pitting corrosion resistance after 72 testing hours per ASTM G481 or general corrosion resistance after 42 days of salt spray test per ASTM(1) B1172 or Sulfide Stress Cracking (SSC) resistance after 720 hours per NACE(2) TM03163 of the low alloy steel. However, in the case of stainless steel, the laser marking process was found to slightly to significantly affect the general corrosion resistance and SSC resistance of the stainless steel. One set of the laser marked stainless steel failed the SSC test while the unmarked specimen, tested in the same testing batch, passed. This illustrates the need to understand the potential effect of laser marking on corrosion resistance for a given material grade.