| 摘要 |
<p>A heat-treatment steel for springs which is to be subjected to cold coiling, can combine sufficient atmospheric strength with coilability, and has a tensile strength of 2,000 MPa or higher. Through a heat treatment after spring formation, the steel can heighten performances required of springs. The heat-treatment steel for high-strength springs is characterized by containing, in terms of mass%, 0.4-0.9% C, 1.0-3.0% Si, 0.1-2.0% Mn, and 0.1-1.0%, excluding 0.1%, V, the amount of N being 0.007% or less and the remainder being iron and unavoidable impurities. It is further characterized in that after the heat treatment, a subsequent extraction residue analysis gives results which satisfy the relationship [amount of V present in filtrate resulting from filtration through 0.2-mum filter (mass%)]>=[amount of V contained in steel (mass%)]80.4.</p> |
