| 摘要 |
PROBLEM TO BE SOLVED: To provide a steel wire rod achieving the excellent cold-forgeability after softening-annealing with which the softening-annealing time before cold-forging can be shortened, and to provide a method for production thereof. SOLUTION: This steel wire rod is composed, by mass%, of 0.005-0.60% C, 0.01-0.40% Si, 0.20-1.80% Mn,≤0.040% P,≤0.050% S and the balance Fe with inevitable impurities, and the metallurgical structure is constituted of pro-eutectoid ferritic structure and pearlitic structure, and bainitic structure, and the volume ratio of the pro-eutectoid ferrite is≤40%, and the pearlitic structure or the bainitic structure (as the structure I in the following) having <5 average aspect ratio of carbide, is contained with 10-50% volume ratio, and the pearlitic structure having≥5 average aspect ratio (as the structure II in the following) is contained with≥30% volume ratio. COPYRIGHT: (C)2010,JPO&INPIT
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