| 摘要 |
<p>The present invention relates to austenitic steel having improved machinability and cryogenic toughness in a weld heat-affected zone and a manufacturing method thereof. The austenitic steel includes 15 to 35 wt% of manganese (Mn), carbon (C) satisfying 23.6C+Mn>=28 and 33.5C-Mn<=23, 5 wt% or less (except 0 wt%) of copper (Cu), chrome (Cr) satisfying 28.5C+4.4Cr<=57 (except 0 wt%), 0.03 to 0.1 wt% of sulfur (S), 0.001 to 0.01 wt% of calcium (Ca), the remaining amount of Fe, and other inevitable impurities, wherein a charpy impact value at -196°C of the weld heat-affected zone is 41J or more. According to the present invention, the cryogenic steel can be obtained at a low cost, the austenitic phase can be formed stably at a low temperature, and the formation of carbide can be effectively suppressed.</p> |
