| Popis: |
The stress corrosion cracking (SCC) susceptibility of 410 stainless steel in boiling 3% NaCl solutions of pH 6.2 and pH 5.1 and in boiling 3% NH4Cl solution of pH 5.1 was investigated using the constant-load technique. The stainless steel was tested in the as-received, the annealed and the quenched and tempered conditions with yield stresses of 233.55 N mm−2, 175.16 N mm−2 and 603.35 N mm−2 respectively. In NaCl solutions, cathodic polarization decelerated SCC while anodic polarization accelerated it. However, in NH4Cl solution SCC was accelerated when the alloy was either cathodically or anodically polarized. The lifetime was shortest for the quenched and tempered condition in all solutions tested. The results indicate that the cracking of 410 stainless steel in NaCl solutions is mainly due to an active path corrosion mechanism. However, in NH4Cl solution both hydrogen embrittlement and the active path mechanism may be operative. |
