| 摘要 |
<p>The purpose of the present invention is to provide: an untempered steel for hot casting which is available in induction hardening; a hot-casted untempered article, in which the structure therein is controlled in the process of cooling following the hot-casting so as to prevent lowering in machinability associated with high strength, thereby improving fatigue strength; and a method for producing the same. The steel according to the present invention is characterized by comprising, in terms of mass%: 0.45-0.60% of C; 0.02-0.15% of Si; 1.50-3.00% of Mn; 0.0002-0.150% of P; 0.001-0.200% of S; 0.02-1.00% of Cr; 0.001-0.300% of Al; 0.01-0.30% of V; 0.03-1.00% of Mo; 0.0020-0.0070% of N; and the balance being Fe and unavoidable impurities. The hot-casted untempered article, which can be induction-hardened, having the aforesaid steel composition, comprising a bainitic structure amounting to 95% or greater, in terms of area, of the steel structure, and containing Mo carbonitride dispersed in the steel, and the method for producing the same.</p> |
