| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel material which has superior break separableness while having a low strength level and is useful as a material of a cracking connecting rod and the like, and to provide a manufacturing method therefore. SOLUTION: The low-hardness steel superior in break separableness and machinability for a machine structure comprises, by mass%, 0.50 to 0.70% C, 0.40% or less Si, 0.90% or less Mn, 0.01 to 0.15% P, 0.002 to 0.03% S, 0.05% or less Al and the balance Fe with impurities; and includes former austenite grains with an average size of 100μm or larger. The steel may further include 0.30% or less Ti. The manufacturing method includes heating a hot-worked material at 1,150°C or higher for 30 minutes or longer. COPYRIGHT: (C)2008,JPO&INPIT
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