| 摘要 |
This case hardened steel has a composition including, in mass %: C: 0.05 to 0.45%; Si: 0.01 to 1.0%; Mn: over 0 to 2.0%; Al: 0.001 to 0.06%, N: 0.002 to 0.03%, S: over 0 to 0.1%, P: over 0 to 0.05%; and balance: Fe and inevitable impurities. Equation (1) described below and Equation (2) described below are satisfied in equiaxed zone, or Equation (3) described below is satisfied in columnar zone.;Re=(Ae/Ao)×100≦30% Equation (1);(Cmin,1/Co)≧0.95 Equation (2);(Cmin,2/Co)≧0.95 Equation (3) |
