Wear-resistant steel plate having excellent wear resistance at high temperatures and excellent bending workability and method for manufacturing the same

Abstract

This wear-resistant steel plate includes, in terms of mass %, C: not less than 0.13% and not more than 0.18%, Si: not less than 0.5% but less than 1.0%, Mn: not less than 0.2% and not more than 0.8%, P: not more than 0.020%, S: not more than 0.010%, Cr: not less than 0.5% and not more than 2.0%, Mo: not less than 0.03% and not more than 0.30%, Nb: more than 0.03% but not more than 0.10%, Al: not less than 0.01% and not more than 0.20%, B: not less than 0.0005% and not more than 0.0030%, and N: not more than 0.010%, with a remainder being Fe and unavoidable impurities, wherein an element composition is such that HI is 0.7 or greater and Ceq exceeds 0.50, and an HB value (Brinell hardness) at 25° C. is not less than 360 and not more than 440.

1 . A wear-resistant steel plate having excellent wear resistance at high temperatures and excellent bending workability, comprising, in terms of mass %,
 C: not less than 0.13% and not more than 0.18%,   Si: not less than 0.5% but less than 1.0%,   Mn: not less than 0.2% and not more than 0.8%,   P: not more than 0.020%,   S: not more than 0.010%,   Cr: not less than 0.5% and not more than 2.0%,   Mo: not less than 0.03% and not more than 0.30%,   Nb: more than 0.03% but not more than 0.10%,   Al: not less than 0.01% and not more than 0.20%,   B: not less than 0.0005% and not more than 0.0030%, and   N: not more than 0.010%,   with a remainder being Fe and unavoidable impurities,   wherein an element composition is such that HI defined below is 0.7 or greater and Ceq defined below exceeds 0.50, and   an HB value (Brinell hardness) at 25° C. is not less than 360 and not more than 440,
   HI=[C]+0.59[Si]−0.58[Mn]+0.29[Cr]+0.39[Mo]+2.11([Nb]−0.02)−0.72[Ti]+0.56[V] 
   C eq =[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14 
   wherein [C], [Si], [Mn], [Ni], [Cr], [Mo], [Nb], [Ti] and [V] represent amounts (mass %) of C, Si, Mn, Ni, Cr, Mo, Nb, Ti and V, respectively.   
     
     
         2 . A wear-resistant steel plate having excellent wear resistance at high temperatures and excellent bending workability according to  claim 1 ,
 wherein the steel plate further comprises, in terms of mass %, one or more selected from the group consisting of Cu: not less than 0.05% and not more than 1.5%, Ni: not less than 0.05% and not more than 1.0%, Ti: not less than 0.003% and not more than 0.03%, and V: not less than 0.01% and not more than 0.20%.   
     
     
         3 . A method for manufacturing a wear-resistant steel plate having excellent wear resistance at high temperatures and excellent bending workability, the method comprising:
 heating a slab having a composition defined in  claim 1  or  2  to a temperature of at least 1,200° C., conducting hot rolling with a cumulative reduction ratio of not less than 30% and not more than 65% at a temperature of not more than 960° C. and not less than 900° C., finishing said hot rolling at a temperature of not less than 900° C.; and   after completion of said hot rolling, either immediately performing accelerated cooling to a temperature of 200° C. or lower such that a cooling rate within a plate thickness center portion is at least 5° C./s, or conducting cooling to a temperature of 200° C. or lower, subsequently reheating to a temperature of not less than an Ac3 transformation point, and then performing accelerated cooling to a temperature of 200° C. or lower such that a cooling rate within a plate thickness center portion is at least 5° C./s.