济南锻件冲孔后外形尺寸将发生变化，一般是高度方向尺寸变小，径向尺寸变大。锻造比是锻造时金属变形程度的一种表示方法。锻造比以金属变形前后的横断面积的比值来表示。不同的锻造工序，锻造比的计算方法各不相同。

　　The dimension of the forging will change after punching, generally the height direction, the dimension become smaller, and the radial dimension will become larger. The forging ratio is a representation of the extent of metal deformation during forging. The forging ratio is expressed as a ratio of the cross-sectional area before and after deformation of the metal. In different forging processes, the calculation methods of forging ratio are different.

　　1、拔长锻造比：拔长前横截面积与拔长后横截面积之比

　　1. Long forging ratio: ratio of cross-sectional area to cross-sectional area before pulling out

　　2、镦粗锻造比：镦粗后横截面积与镦粗前横截面积之比

　　2. Ratio of upsetting to forging: ratio of cross-sectional area to upsetting cross section area after upsetting

　　锻造比通常是用拔长时的变形程度来衡量。是指你所要进行成形的材料的用料长度与直径之比或锻造前的原材料(或预制坯料)的截面积与锻造后的成品截面积的比。锻造比的大小影响金属的力学性能和锻件质量，增加锻造比有利于改善金属的组织与性能，但锻造比过大也无益。

　　The forging ratio is usually measured by the extent of deformation at the time of pulling out. The ratio of the length of material to the diameter of the material to be formed or the cross-sectional area of the raw material (or preform) before the forging and the cross-sectional area of the finished product. The size of the forging ratio affects the mechanical properties and quality of the metal, and the increase of the forging ratio is beneficial to improve the microstructure and properties of the metal, but the forging ratio is too great to be beneficial.