Patent ID: 9738957
Date: 2017-08-22
CPC Classifications: C21D,C22C

Claim:
1. A wear resistant steel plate having a chemical composition comprising, by mass %: C: 0.25% to 0.33%; Si: 0.1% to 1.0%; Mn: 0.40% to 1.3%; P: 0.010% or less; S: 0.004% or less; Al: 0.06% or less; N: 0.007% or less; at least one selected from the group consisting of Cu: 1.5% or less, Ni: 2.0% or less, Cr: 3.0% or less, Mo: 1.5% or less, W: 1.5% or less, and B: 0.0030% or less; and the balance including Fe and incidental impurities, wherein DI* defined by the following Formula 1 is in a range of 100 to 250, where the symbols of elements represent the respective contents by mass % of the elements, a surface layer part of the steel plate includes 90% or more in area ratio of martensite, the surface layer part representing a zone extending up to a depth of 1 mm from a surface of the steel plate, the surface of the steel plate having a Brinell hardness of 450 HBW 10/3000 or more, and a central part of the steel plate in a thickness direction includes 70% or more in area ratio of lower bainite having an average grain size of 25 μm or less, the central part representing a zone extending from a ½ position of the steel plate in the thickness direction up to 0.5 mm toward both surfaces of the steel plate.