抄録
The effect of heat treatments and minor elements (C, S, P, N) on caustic stress corrosion cracking of Type 304 stainless steel in boiling 34%NaOH solution at 393K was studied. The results obtained as follows:
(1) Susceptibility to IGSCC (intergranular stress corrosion cracking) in NaOH solution was increased with the intergranular precipitation of chromium carbides by the sensitizing heat treatments, but was not completely consistent with the susceptibility to IGC (intergranular corrosion) by Strauss test in H2SO4+CuSO4 solution.
(2) SCC in NaOH solution took place in three potential ranges of about -100 to +150mV (vs SCE), -600 to -300mV and -1100 to -900mV. Transglanular crackingpredominan tly occurred in the first region and intergranular cracking occurred in the latter two regions. IGC occurred in the potential range of about -400 to 0mV. No IGC was observed at corrosion potential.
(3) Among minor elements carbon and sulfur had a detrimental effect on SCC, but no effect of phosphorus and nitrogen was almost observed on SCC in NaOH solution.
