| 摘要 |
PROBLEM TO BE SOLVED: To secure the cold forgeability of an inexpensive highly corrosion-resistant two-phase stainless steel wire, for inexpensively producing a high-strength highly corrosion-resistant bolt, and further, to impart high strength to a bolt product. SOLUTION: Disclosed is an austenitic-ferritic two-phase steel wire rod for a high-strength highly corrosion-resistant bolt having excellent cold forgeability, which has a composition comprising, by mass, 0.005 to 0.05% C, 0.1 to 1.0% Si, 0.1 to 10.0% Mn, 1.0 to 6.0% Ni, 19.0 to 30.0% Cr, 0.05 to 3.0% Cu and 0.005 to 0.20% N, and the balance Fe with substantially inevitable impurities, wherein C+N;≤0.20%, M value in formula (a); M=551-462(C+N)-9.2Si-8.1Mn-29(Ni+Cu)-13.7Cr-18.5Mo, is≤60, F value in formula (b); F=5.6Cr-7.1Ni+2.4Mo+15Si-3.1Mn-300C-134N-26.6, is 45 to 85, and tensile strength is controlled to 550 to 750 N/mm<SP>2</SP>. If required, Mo, B, Al, Mg, Ca, Nb, Ti, Zr and V may be added thereto. COPYRIGHT: (C)2009,JPO&INPIT
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