듀플렉스강의 레이저 열처리

Laser surface treatment of duplex stainless steel

Duplex stainless steel is a preferred material for a high temperature and pressure pump of a seawater desalination plant due to its high corrosion resistance and hardness. Despite the good hardness of duplex stainless steel, rotating pump components such as ring, bush, or sleeve require regular replacements due to friction wear, requiring surface treatment of those rotating components for obtaining higher surface hardness. In this work, experimental results for CW laser heat treatment and laser peening of duplex stainless steel for an enhancement of surface hardness are reported. In CW laser heat treatment, irradiation with a Nd-YAG laser and quenching with liquid nitrogen was carried out. while in laser peening a pulsed Nd-YAG laser irradiation was conducted in a water chamber. The results revealed that CW laser irradiation could not improve surface hardness of duplex stainless steel, whereas laser peening showed evidences of surface hardness improvement.