Corrosion Fatigue of AISI Type 316LN Stainless Steel and its Weld Metal

Abstract This paper describes the results obtained on the corrosion fatigue behavior of Type 316LN (UNS S31653) stainless steel base metal in boiling acidified sodium chloride (NaCl) solution, and of Type 316LN stainless steel base metal and Type 316N stainless steel weld metal obtained in boiling 45% magnesium chloride (MgCl2) solution. Type 316LN stainless steel base metal was tested using the fracture mechanics approach under different loading and environmental conditions, while smooth specimens were used to compare the base and weld metals. In the studies on Type 316LN stainless steel base metal carried out at a frequency of 0.1 Hz, with different stress ratios (R-ratios) adjusted by varying both the maximum and minimum stress intensity factors, Kmax and min, respectively, crack growth rate per cycle (da/dN) increased slightly with increasing R-ratio. At both R-ratios, a significant rise in da/dN was observed at values of ΔK (= Kmax - Kmin) greater than KISCC (= 27.5 MPa.m0.5) of the material. Contrar...