一般的挤压设备不适于生产沿其长度带有规律变化的横断面的管子,例如沿其外表面长度具有螺旋形结构或花纹的管子。挤压有这种外形的管子的设备至今尚未问世。这种管的特点是,其横断面沿管子长度的相继点上依次旋转。本发明的主要目的是提供在管子上成形这种螺旋形状的挤压模装置。它包括挤压模,以及装在模中并伸入模座的长芯棒。沿芯棒长度上带有一些有间距的螺旋形筋。当加热金属被压到芯棒周围并通过模子时,芯棒上的筋在塑性金属中形成相应的槽或筋。 Conventional extrusion equipment is not suitable for the production of tubes with regularly varying cross-sections along their length, for example tubes having a helical structure or pattern along their outer surface length. Equipment that squeezes tubes with this profile has not yet come out. This tube is characterized by its cross-section along the tube length of successive points on the turn. The main object of the present invention is to provide an extrusion die device for forming such a spiral shape on a pipe. It includes an extrusion die, and a long mandrel mounted in the die and extending into the die holder. Spiral ribs along the length of the mandrel with some pitch. When heated metal is pressed around the mandrel and passes through the mold, the bars on the mandrel form corresponding grooves or ribs in the plastic metal.