Effect of Plasma Nitriding on Corrosion Behavior of AISI4330 Low Alloy Steel

摘要

Plasma nitriding is a surface treatment process, which is widely used to improve wear, fatigue and corrosion resistance of the industrial parts. In this study, the corrosion behavior of plasma nitrided and untreated AISI4330 steel samples was compared. Plasma nitriding of conventionally heat treated AISI4330 steel samples were performed at 480 °C for 5, 10 and 14h and the gathered properties were assessed by evaluating hardness profile, compound layer thickness, case depth and surface roughness by using microhardness tester, scanning electron microscopy, optical microscopy, surface profilometer and X-ray diffraction. It has been found that the thickness of the compound layer increases with increasing treatment time. The surface roughness, the surface hardness, the hardness profile, the case depth, the compound layer thickness, and phase content of the compound layer depend on nitriding parameters. The corrosion tests were carried out with Potentiodynamic polarization technique in 3.5 % NaCl solution. The result shows that, the corrosion resistance and surface hardness of the AISI4330 steel increased with an increase in plasma nitriding time. The plasma nitriding raises the surface hardness up to 710 Hv. The reasons for increase in corrosion resistance have been discussed in this paper.