Subcritical crack growth was studied in an En 31 ball race steel subjected to various fluids, some of which are suitable for possible use in high pressure applications. Using fracture mechanics techniques of measurement and analysis, it was found that Esso Univis P38, Shell Tellus 15, and a 25 per cent glycerine–ethylene glycol mixture caused subcritical crack growth with a corrosion stress intensity threshold approximately half that obtained in air. Diesel oil had no effect. Evidence of blunting of the crack system and some effects of history were found.
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CoxB. G.ParryJ. S. C.‘The fracture behaviour of En 31 1 per cent C–Cr steel in relation to its use for high pressure containers.’ To be published.
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CarterC. S.‘Crack extension in several high strength steels loaded in 3·5 per cent sodium chloride solution’, Boeing Document D6–19770, 1967. (Available from National Lending Library, Boston Spa.).
