| 摘要 |
PROBLEM TO BE SOLVED: To provide a wear resistant steel sheet excellent in low temperature tempering brittle crack resistance. SOLUTION: The steel sheet has a composition containing specified amounts of C, Si, Mn, Ti, B, Al, P and S, comprising one or more kinds selected from Cu, Ni, Cr, Mo, V and W, and, if required, comprising one or more kinds selected from Ca, REM and Nb, and in which ceq*=C+Mn/6+(Cu+Ni)/15+(Cr+Mo+V)/5+W/10 is≤0.55% and DI*=33.85×(0.1×C)<SP>0.5</SP>×(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, and the balance Fe with inevitable impurities, and also has a microstructure where a base phase is composed of martensite with the austenite grain size of≤30μm, and whose surface hardness is≥400HBW10/3000 by Brinell hardness. COPYRIGHT: (C)2009,JPO&INPIT
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