Official Answer
Answer
Don tsarin mai na ƙarƙashin teku ko cryogenic, zaɓin abu dole ne a yi lissafin zafin canjin Ductile-to-Brittle (DBTT). Karfe na carbon ya zama mai karyewa sosai a yanayin zafi ƙasa da $-30^{\circ}C$, yana sa su rashin dacewa. Austenitic bakin karfe kamar 302 da 316, da hazo-hardening gami kamar 17-7PH, kasance ductile a cryogenic yanayin zafi (har zuwa $-196 ^{\circ}C$ ko $77K$). Yayin da Modulus na Elasticity $ E$ ya ƙaru kaɗan (ta kusan $5-10 \%$) a ƙananan yanayin zafi, yana haifar da haɓaka daidai gwargwado a cikin lokacin bazara, babban abin damuwa shine taurin. Kayan aiki kamar Elgiloy ko Inconel 718 galibi ana keɓance su don ƙaƙƙarfan ƙarfinsu da rashin DBTT a cikin ruwa nitrogen ko muhallin oxygen na ruwa.
