| 摘要 |
PURPOSE:To obtain PC piles having excellent impact resistance by a method in which high-tensile iron bars ade of martensitic steel wires subjected to tempering process are welded to a spiral iron bar as a cross beam, the welded portions are tempered, and the iron bars in tensed state are buried in concrete. CONSTITUTION:High-tensile iron bars 1, obtained by subjecting wire materials containing 0.4% or less carbon and a martensite structure formed by cooling controlled from a temperature below 700 deg.C after hot rolling to a tempering process without passing through drawing process, are arranged on the circumferential side of a concrete product form. Then, an iron bar 2 is spirally wound around the periphery of the high-tensile iron bars 1 and spot-welded by flowing about 2,500-3,250A of current in the spot welding electrode of movable electrode in about 2-4 cycles. The welded portions are tempered by flowing about 2,750-3,500A of current in the tempering electrode in about 2-4 cycles. The iron bars in tensed state are buried in concrete to bring the elongation at breakage of the high-tensile iron bars 1 to 8.1% or more. |
