Assessment of acoustic emission generated during stress corrosion crack growth in AISI type 304 stainless steel

Pre-cracked compact tension specimens of AISI type 304 stainless steel were tested for stress corrosion cracking (SCC) in acidified NaCl solution at 381 K. Crack growth rates were measured for the specimen in solution annealed, sensitised and 10% cold worked conditions. Acoustic emissions recorded during crack growth and the crack arrest marks on the fracture surfaces indicated that the crack advance was discontinuous and crack growth per event varied from less than a micron for solution annealed material to 15 micron for 10% cold worked material. These observations combined with diffusivity calculations and measured activation energy for crack growth process showed that hydrogen plays a significant role in the cracking process.