Effects of laser surface melting on erosion-corrosion of X65 steel in liquid-solid jet impingement conditions

Laser surface melting (LSM) has the potential to increase the resistance of steels to erosion-corrosion. In this study a submerged jet impingement system containing a brine under saturated CO2 conditions with sand has been used to assess the effect of LSM on the erosion-corrosion resistance of X65 steel. Erosion-corrosion rates under different experimental conditions were deduced based on CFD-simulated results and surface profile measurements. Scanning electron microscopy (SEM) was used to observe the morphology of erosion-corrosion damage. The results show that the erosion-corrosion rates at various impact angles can be decreased by LSM. Changes in microstructure, corrosion behavior and hardness of X65 steel induced by laser treatment were analyzed by using optical microscopy, transmission electron microscopy (TEM), energy dispersive X−ray (EDX) analysis together with electrochemical polarization and hardness distribution measurements, in order to clarify how laser treatment imparts the effects on the steel.