一、前言金属材料在进行压延成形时,σ_(0.2)/σ_b比值的大小对压延性能有重要影响。σ_(0.2)/σ_b高,成形时材料比较难于进入塑性状态,而当一开始进入塑性状态,变形抵抗力又会很快达到σ_b而使零件破坏。此外,σ_(0.2)/σ_b高时,又容易使毛料突缘部分在切向压应力的作用下 I. Preface The metal material in the rolling forming, σ_ (0.2) / σ_b ratio of the size of rolling has an important impact on performance. σ_ (0.2) / σ_b high, forming materials more difficult to enter the plastic state, and when the beginning into the plastic state, the deformation resistance will soon reach σ_b and make the parts destroyed. In addition, σ_ (0.2) / σ_b high, it is easy to make wool flange part under the tangential compressive stress