| 摘要 |
<p>An inexpensive heat resistant steel for use in an engine valve is provided by allowing an iron-based heat resistant steel to exhibit high-temperature strength comparable to that of a nickel-based heat resistant alloy. The heat resistant steel for use in an engine valve having excellent high-temperature strength comprises, in terms of mass%, 0.20 to 0.50% of C, not more than 1.0% of Si, not more than 5.0% of Mn, 0.1 to 0.5% of P, 8.0 to 15.0% of Ni, 16.0 to 25.0% of Cr, 2.0 to 5.0% of Mo, not more than 0.5% of Cu, not more than 1.0% of Nb (including no addition), not more than 8.0% of W (including no addition), 0.02 to 0.2% of N, not more than 0.01% of B, and Fe and impurities as the remainder, and satisfies relational formula (1): 442P (%) + 12Mo (%) + 5W (%) + 7Nb (%) + 328N (%) + 171 = 300 and relational formula (2): -38.13P (%) + 1.06Mo (%) + 0.13W (%) + 9.64Nb (%) + 13.52N (%) + 4.83 = 0.12.</p> |
