濟南鍛件沖孔后外形尺寸將發生變化，一般是高度方向尺寸變小，徑向尺寸變大。鍛造比是鍛造時金屬變形程度的一種表示方法。鍛造比以金屬變形前后的橫斷面積的比值來表示。不同的鍛造工序，鍛造比的計算方法各不相同。

　　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、拔長鍛造比：拔長前橫截面積與拔長后橫截面積之比

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

　　2、鐓粗鍛造比：鐓粗后橫截面積與鐓粗前橫截面積之比

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

　　鍛造比通常是用拔長時的變形程度來衡量。是指你所要進行成形的材料的用料長度與直徑之比或鍛造前的原材料(或預制坯料)的截面積與鍛造后的成品截面積的比。鍛造比的大小影響金屬的力學性能和鍛件質量，增加鍛造比有利于改善金屬的組織與性能，但鍛造比過大也無益。

　　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.