无芯冷缩径工艺是一种无约束正挤压加工方法。它适用于内径和壁厚尺寸无严格要求的管件生产。我们经过试验研究,把该工艺成功地应用在东风4型内燃机车接线端子(图1)的生产上,取得了较好的效果。该工件材质为T_2紫铜,过去是加热后在1/4吨汽锤上用胎摔,每件需锤击几十次,生产效率很低, Coreless shrinking process is a kind of unconstrained positive extrusion processing method. It applies to the diameter and wall thickness without strict requirements of pipe production. After the pilot study, we successfully applied the technology to the production of the terminal block of DF4 diesel locomotive (Figure 1) and achieved good results. The workpiece material for the T_2 copper, the past is heated in the 1/4 ton hammer on the tire fell, each hammer to dozens of times, the production efficiency is very low,