Abstract
The behavior of hydrogen induced slow crack growth in type 310 and type 16-20-10 stable austenitic stainless steels along with type 321 unstable austenitic stainless steel were investigated. It was found that slow crack growth could occur in all three types of stainless steels, and the threshold values wereK H/Kc = 0.55, 0.7, and 0.78 for type 321, 310, and 16-20-10 stainless steel respectively, when charged under load. Slow crack growth could also occur if the precharged specimens were tested under constant load in air. No slow crack growth occurred in the precharged and then out-gassed specimens. This indicates that delayed cracking in stable austenitic stainless steels is induced by hydrogen. Since there is no hydrogen induced α’ martensite in type 310 and 16-20-10 stainless steel, the existence of a’ martensite is not necessary for the occurrence of slow crack growth in the austenitic stainless steels, although it can facilitate slow crack growth. The mode of hydrogen induced delayed fracture in either the stable or unstable austenitic stainless steel is correlated with theK, value; the fracture surface is changed from ductile to brittle asK 1 is decreased.
Published Version
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