| 摘要 |
<p>The present invention provides a steel material for hardening, including chemical components, by mass%, of C: 0.15 to 0.60%; Si: 0.01 to 1.5%; Mn: 0.05 to 2.5%; P: 0.005 to 0.20%; S: 0.001 to 0.35%; Al: over 0.06 to 0.3%; total N: 0.006 to 0.03%; Cr: 0.1 to 3.0%; and B: limited to not more than 0.0004%, with a balance including Fe and inevitable impurities, wherein R and H satisfy following Equation (1), where the R is a hardness at a position 5 mm away from a quenching end measured through a Jominy-type end-quenching method specified in JIS G 0561, and the H is a calculation hardness at a position 4.763 mm away from the quenching end, the H being obtained through a procedure 1 as described in paragraphs [0078] and [0079] of the description, a procedure 2 as described in paragraphs [0080] to [0086] of the description, and a procedure 3 as described in paragraph [0087] of the description, and
the chemical components further include, in mass%, Ti: 0.001 to 0.05%, wherein [total N] and [Ti] satisfy following Equation (2), where [total N] is total amount (%) of N, and [Ti] is amount (%) of Ti. H × 0.948 ‰¤ R ‰¤ H × 1.05 0.006 + Ti × 14 / 48 ‰¤ total N ‰¤ 0.03</p> |
