| 摘要 |
An abrasion resistant steel plate which is excellent in toughness and delayed fracture resistance of a multi pass weld and is preferably used in construction machines, industrial machines and the like is provided. To be more specific, the composition of the steel plate contains by mass% 0.20 to 0.30% C, 0.05 to 1.0% Si, 0.40 to 1.2% Mn, 0.010% or less P, 0.005% or less S, 0.40 to 1.5% Cr, 0.005 to 0.025% Nb, 0.05 to 1.0% Mo, 0.005 to 0.03% Ti, 0.1% or less Al, 0.01% or less N, and 0. 0003 to 0. 0020% B, and further contains one, two or more kinds of components selected from a group consisting of W, Cu, Ni, V, REM, Ca and Mg when necessary, wherein DI* (DI* = 33.85 × (0.1×C) 0.5 × (0.7×Si+1) × (3.33×Mn+1) × (0.35×Cu+1) × (0.36×Ni+1) × (2.16×Cr+1) × (3×Mo+1) × (1.75×V+1) × (1.5×W+1)) is 45 to 180, C+Mn/4-Cr/3+10P‰¤0.47, and a base phase of the microstructure is formed of martensite. |
