本文研究微合金钢49M_nVS_3的一种专门用途——对汽车曲轴的适用性。微量合金添加剂的作用。为了合理地选择某一专用钢的成份,应当充分研究钢的强化机理。钢的强化机理,可用下述公式表示:σ_y=σ_D+σ_s+σ_G+σ_A。式中σ_D=位错密度引起的强化;σ_S=固溶引起的强化;σ_S=晶粒度细化引起的强化;σ_A=时效硬化引起的强化。钢的总强化是这些强化共同作用的结果。其中第一、第三和第四种因素,影响较大。为了利用这些强化作用需要一定的淬火回火条件。 This article studies a specialized use of microalloyed steel 49M_nVS_3 - its applicability to automotive crankshafts. The role of trace alloy additives. In order to reasonably choose the composition of a special steel, steel strengthening mechanism should be fully studied. The strengthening mechanism of steel can be expressed by the following formula: σ_y = σ_D + σ_s + σ_G + σ_A. Where σ_D = enhancement due to dislocation density; σ_S = strengthening due to solid solution; σ_S = strengthening due to grain refinement; and σ_A = strengthening due to age hardening. The total strengthening of steel is the result of these intensified interactions. Among them, the first, third and fourth factors have great impact. In order to use these strengthening effect requires a certain quenching and tempering conditions.