| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a high-strength galvanized bolt having corrosion resistance, excellent hydrogen embrittlement resistance, and a strength of ≥1,200 MPa. <P>SOLUTION: In the method for manufacturing the high-strength galvanized bolt having excellent hydrogen embrittlement resistance and a strength of ≥1,200 MPa, a steel material used has a composition comprising, by mass%, 0.70-1.10% C, 0.05-2.00% Si, 0.20-2.00% Mn; ≤0.020% P, ≤0.020% S, 0.0150% or less N; one or more kinds of 0.005-0.100% Al, 0.002-0.100% Ti, and 0.002-0.100% Nb; and the balance being Fe and inevitable impurities. The steel material is hot-rolled and then cooled to a temperature range of 550-700°C at a cooling velocity of ≥30°C/s and held at the temperature range for 30-300 s. Then the steel material is cooled to a room temperature, and subjected to a drawing work with a friction coefficient of ≤0.1. Then the steel material is formed into a bolt shape, and electrogalvanized or hot-dip galvanized. <P>COPYRIGHT: (C)2012,JPO&INPIT |
