Effect of Predeformation on Corrosion Fatigue Crack Growth of Type 316NG Steel in 325°C Deaerated Water

The predeformed 316NG (00Cr17Ni12Mo2N) was prepared by cold rolling at room temperature and hot rolling at 400 degrees C. The effect of predeformation on fatigue crack growth both in 325 degrees C deaerated water and room temperature air was investigated. The effect of predeformation on corrosion fatigue crack growth (CFCG) in 325 degrees C deaerated water was much smaller than that on fatigue crack growth. The cold rolling significantly enhanced CFCG rates while the applied Delta K closed to 11 MPapm or the applied loading frequency decreased to 0.1 Hz. The accelerating effect of hot rolling on CFCG tended to become evident until the predeformation increased to 30%. Dynamic recovery was observed near the corrosion fatigue crack tip in hot-rolled 316NG, which may result in relatively low CFCG rates.