(2) The production of stainless steel seamless tube extrusion process used mainly as production technology, although some units can produce hot-rolled stainless steel tube, but the extrusion unit is the world's production of stainless steel seamless pipe main unit. 60 sets available in the world extrusion unit, except for a few for extrusion, 70% of the units for the production of steel, the main varieties of stainless steel tube. And rolling (longitudinal rolling and cross rolling) production method, characterized by extrusion of metal deformation process under the three-compression stress.

In this best stress state, for the steel and more resistance to deformation large stainless steel tube, can get better deformation, internal and external surface quality and microstructure. Vertical hydraulic equipment, piercing process improvement, the shortage can extrusion wall thickness deviation of accuracy of 5% to 7%. Extrusion die mechanic is simple, easy to manufacture and replacement, suitable for small-volume, multi-standard stainless steel production. Extrusion unit can also produce a wide range of pipe size, 1 set of 50MN (5000t) in the extrusion unit produces specifications for the 25 ~ 245mm steel pipe, meet the market demand is far higher than other pipe mill. Production of stainless steel by squeeze the maximum benefit can be used directly as a slab of raw materials, product quality, variety replacement of flexible, direct production of finished tube extrusion, but also can produce all kinds of profiled stainless steel tube. However, the disadvantage of extrusion is the production rate of finished steel is low. In order to improve the finished product rate, foreign manufacturers to improve the production process.

High demand for the varieties commonly used pre-drilling, reaming hydraulic punch and squeeze into the pipe production process. Raw materials for the general requirements of the cold tube can be different depending on the circumstances of the production process: small size directly from solid billet steel vertical hydraulic punch a hole and squeeze into a tube; medium size steel billet used in pre-drilled holes as far as possible, legislation Hydraulic punching machine reaming and squeeze into a tube; large size steel billet used in the larger pre-drilled hole, directly into the extruder into a tube.

Clearly, the use of extrusion for the production of cold finished tubes and pipes to provide waste material, thermal processing abroad is widely used stainless steel tube as a more economical production methods. With high-speed, automation, extrusion machine with large tonnage, and the glass lubricants, non-oxidative heating, high strength and toughness of hot die, and other related technologies, with the production of stainless steel seamless pipe hot extrusion method, in particular, deformation of the stainless steel production is difficult, high-alloy steel pipe has been developing rapidly. The use of a single two-roll piercing cold to provide for the shortage of pipe materials, production methods, foreign countries have basically no longer used.