| 摘要 |
A non-heat-treating steel for hot forging which does not require heat treatment and still yields high static strength, toughness and fatigue resistance only by air cooling after hot forging. The main ingredients are, by weight %, 0.10-0.30% C, 0.05-0.50% Si, 0.80-2.00% Mn, 0.30-1.50% Cr, 0.05-0.50% Mo, 0.002-0.060% Al, 0.05-0.50% V, 0.008-0,020% N, and the balance Fe and inevitable impurities, where contents of some component elements should satisfy the following conditions, %Mo+%V>/=0.20(%), 1.8x%Mn+%Cr+0.5x%Mo</=20x%C, and Bs>/=550( DEG C.) where Bs represents the bainite transformation temperature and is defined by Bs=830-270xC%-90xMn%-70xCr%-83xMo%. Since the mechanical properties are obtained through air cooling, the mechanical properties are stable albeit the size of the forged article and the forging conditions. The non-heat-treating steel is especially suited for use in chassis parts of automobiles and hydraulic parts of construction machines.
|
