Effect of Thermal Cycle and Stress on Corrosion Resistance in SUS 304 Stainless Steels

Abstract

It is supposed that the grain boundary precipitation behaviour of chromium carbide and the decrease of corrosion resistance of the welded parts in austenitic stainless steel, with both thermal and strain cycles are different from those in the parts with only thermal cycle.
The effects of stress at elevated temperatures on corrosion resistance in stressd and unstressed specimens (SUS 304) at sensistization temperatures were investigated for different keeping times. The results obtained are as follows:
(1) It was recognized that the decrease of corrsoion resistance was promoted by the keeping stress at elevated temperatures (500°-800°C).
(2) The longer the heating time, the more distinctive was the difference in decrease of corrosion resistance between the stressed and unstreassed specimens at 700°-800°C; it also became more distinctive as the stress was larger or the thermal and strain cycles were longer.
(3) It was also recognized that the corrosionof the restrained parts of weldments were more serious than that of the unstrained parts.