Corrosion resistance of austenitic steels and alloys in high temperature water

An ampoule corrosion tests technique is presented for making a comparative corrosion-proof estimation of austenitic steels and alloys which are candidate materials for the ITER first wall and shield blanket. Influence of Cl- on the rate and character of corrosion cracking has been determined. The dependence of time before destruction on Cl- contents was obtained by experiments in twice-distilled water at a Cl- content value of less than 0.05 mg/l. Kinetics of a corrosion crack growth has been determined by way of acoustic emission and measurement of electrical resistance. It has been revealed, that corrosion cracking of 316L and 316Ti steels in water with 100 mg/l of Cl- takes place at temperatures over 50 C. For 316L (Russian analogue), 316Ti, 08Cr18Ni10Ti (type 304), 00Cr16Ni15Mo3Nb (type 316) steels and CrNiMo-1 (42-47%Cr, 1%Mo, Ni-base) alloy corrosion long-term strength and crack-resistance characteristics were obtained. Results of tests show, that corrosion characteristics are near the same for all austenitic steels under investigation with CrNiMo-1 alloy being the exception. It was not destroyed during ampoule tests. (orig.)