A comparative study of residual stress and affected layer in Aermet100 steel grinding with alumina and cBN wheels

Abstract

Residual stresses induced by finish machining processes have significant effect on fatigue strength of ultra-high strength steel in large structures. In this study, an experimental investigation was carried out to explore the residual stress and affected layer in grinding Aermet100 by using a resin bond white alumina (WA) wheel and cubic boron nitride (cBN) wheel, respectively. The grinding force and temperature were measured, and then the affected layer of residual stress, microhardness, and microstructure by a WA and a cBN wheel was obtained. The comparisons of surface residual stress studies and thermal–mechanical coupling mechanism on the affected layer were discussed in light of the current understanding of this subject. Experimental results show that grinding with cBN wheel can provide compressive residual stress and a smaller affected layer owing to its better thermal conductivity; the coupling effect of wheel speed and grinding depth plays a more significant role on surface residual stress; when grinding with parameters v _w = 18 m/min, v _s = 14 m/s, and a _p = 0.01 mm, compressive residual stress and hardening effect appeared on ground surface, and the depth of residual stress layer is 40~50 μm; the depth of hardened layer is 30~40 μm and the depth of plastic deformation layer is 5~10 μm.