高Mn-Crオーステナイト鋼の液体ヘリウム温度における靱性
1979 年 65 巻 6 号 p. 681-686
詳細
1979 年 65 巻 6 号 p. 681-686
In order to examine the applicability of high manganese-chromium austenitic steels to cryogenic use, Charpy impact test was made at liquid helium temperature. A steel with 25Mn-5Cr-1Ni as base composition exhibited good toughness in impact testing without any sign of martensite transformation induced by impact deformation.
Niobium bearing steel, which was grain-refined, showed slightly lower impact energy. The cause for this was considered to be the local strain hardening in fine-grained steel, in which the mode of crack propagation was changed. Increment of nickel content to the material with base composition increased toughness. 15Mn-5Cr-5Ni steel exhibited good toughness even though the trace of martensite transformation caused by low stability of austenite was found. As the results above, it was shown that 25Mn-5Cr-1Ni austenitic steels have an applicability to cryogenic use.
