BOLT

摘要

Provided is a bolt which has high strength and excellent hydrogen embrittlement resistance characteristics. A bolt according to one embodiment of the present invention contains, in mass%, 0.32-0.39% of C, 0.15% or less of Si, 0.40-0.65% of Mn, 0.020% or less of P, 0.020% or less of S, 0.85-1.25% of Cr, 0.005-0.060% of Al, 0.010-0.050% of Ti, 0.0010-0.0030% of B, 0.0015-0.0080% of N, 0.0015% or less of O, 0-0.05% of Mo, 0-0.05% of V, 0-0.50% of Cu, 0-0.30% of Ni and 0-0.05% of Nb, with the balance made up of Fe and impurities. This bolt is configured to satisfy formula (1) and formula (2), and has a tensile strength of 1,000-1,300 MPa, while satisfying formula (3). 4.9 ≤ 10C + Si + 2Mn + Cr + 4Mo + 5V ≤ 6.1 (1) Mn/Cr ≤ 0.55 (2) (Solid-solved Cr)/Cr ≥ 0.70 (3)