| 摘要 |
PROBLEM TO BE SOLVED: To obtain a PC steel bar which has a low C content, does not cause any problem after welding, does not need a special temperature control, and has a good balance between uniform elongation and strength. SOLUTION: This PC steel bar, excellent in uniform elongation and having a tensile strength of 1,420 N/mm<SP>2</SP>, a 0.2% proof stress of 1,275 N/mm<SP>2</SP>, and a uniform elongation of 5% or higher, is prepared by subjecting steel containing 0.15-0.29 mass% C to hot rolling, then cooling at a cooling rate of 0.2°C/sec or higher to form a martensitic structure, if necessary wire drawing and deforming, and tempering at 350-650°C. COPYRIGHT: (C)2003,JPO
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