自由锻造是利用冲击力或压力使金属在上下砧面间各个方向自由变形，不受任何限制而获得所需形状及尺寸和一定机械性能的锻件的一种加工方法，简称自由锻。

Free forging is a processing method of forging parts, which can make metal in all directi of the anvil between the upper and lower anvil, and obtain the required shape and size and certain mechanical properties by the impact force or pressure, and the free forging is called free forging.

在芯棒上拔长。锻造时，先芯棒插入冲好孔的坯料中，然后当作实心坯料进行拔长。拔长时，一般不是一次拔成，先将坯料拔成六角形，锻到所需长度后，再倒角滚圆，取出芯棒。为便于取出芯棒，芯棒 的工作部分应有1：100 左右的斜度。

Pull on the mandrel. When forging, insert the mandrel into the billet of the hole and then pull it out as a solid billet. When drawing, it is not usually drawn at one time. First, the blank is drawn into a hexagonal shape, forged to the required length, then chamfered and rounded, and the mandrel is removed. To facilitate the removal of the mandrel, the working part of the mandrel should h***e a slope of about 1:100.

镦粗是镦粗示意图使毛坯高度减小，横断面积增大的锻造工序。 镦粗工序主要用于锻造齿轮坯、圆饼类锻件。镦粗工序可以有效地改善坯料***，减小力学性能的异向性。 镦粗与拔长的反复进行，可以改善高合金工具钢中碳化物的形态和分布状态。

Upsetting is the forging process that indicates that the blank height is reduced and the cross section area is increased. The upsetting process is mainly used for forging gear blanks and round cake forgings. The upsetting process can effectively improve the billet structure and reduce the anisotropy of mechanical properties. The morphology and distribution of carbides in high alloy tool steel can be improved by repeated upsetting and drawing.