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In the 1960s due to the invention of a new three-high diagonal mill (known as the Transval mill), this methods have developed rapidly.The new mill is characterized by rapid rotation of the inlet to the rear the turning rack comes to change the rolling Angle, thereby preventing the tail from forming triangles that make the breed of production the ratio of outer diameter to wall thickness is expanded from 12 to 35, which can not only produce thin-walled tubes, but also improve production capacity.

The traditional method of pipe jacking is that the billet is perforated by water pressure and extended into cup wool by cross rolling tube in which a long mandrel is inserted into the bottom of the capillary cup by a push rod and progressively reduced through a series of holes small roll – type die frame, top rolled into tubes.This kind of production method has less investment in equipment and can be used for continuous casting billet, can produce diameter up to 1070mm, the wall thickness to 200mm of the extra thick pipe, but low production efficiency, thicker wall, shorter pipe length than efficiency.After the emergence of the new CPE process,the blank tubes are perforated by cross rolling and extended into tubes by top rolling after closing, which overcomes the traditional method.

Some shortcomings of seamless pipe production has become a better method of economic benefits.
In extrusion pipe production, the peeled round billet is first perforated or reamed and then heated by induction the salt bath is heated, and the inner surface is coated with lubricant and fed into the extruder, through the die hole and through the metal the annular gap between the mandrel is squeezed into steel tubes.

It is mainly used for the production of low plastic superalloy pipes, special-shaped pipes, composite pipes and colored tubes metal pipe, etc.This method has a wide range of production, but low yield.In recent years, due to mold materials, lubricants, extrusion speed and so on have been improved, extrusion pipe production has also developed.

The guide coil rolling tube is also called Diessel perforated capillary tube with long mandrel thin wall steel tubes are rolled on the guide plate mill.A mill is similar to a two – high cross – rolling punch except fixed guide plate is changed to active guide plate.As long mandrel production, steel tube inner wall smooth, and no scratch;But tool cost is big, adjust complex.It is mainly used to produce 150mm outer diameter carbon steel tubes for the following common USES.At present, it is seldom used and has no great development prospect.

Spinning tube production will be flat or hollow blank in the spinning machine through one or more spinning fabricated thin-walled steel pipe.High precision, good mechanical properties, wide range of dimensions, but production efficiency is low.Mainly used in the production of non-ferrous metal steel pipes, but also more and more used in production.

Steel pipe.Except for domestic appliances, chemical containers and machine parts,mostly used in the military industry.
In the 1970s, using the strong spinning method has been able to produce pipe diameter up to 6000mm, diameter and wall thickness the ratio of over 10000 large diameter very thin pipe and shaped pipe fittings.
Cold rolling, cold drawing production for the production of small diameter thin wall, precision and special-shaped steel pipe.raw production features are multi – process cycle process.

In the 1960s, it began to develop in the direction of high-speed, multi-line, long stroke and long tube blank.In addition, small-roll cold rolling pipe mill has also been developed, which is mainly used for the production of extremely thin precision steel pipe with wall thickness less than 1mm. Cold rolling equipment is complex, tool processing is difficult, and variety and specification conversion is not flexible. The combined process of cold rolling and cold drawing is usually adopted, that is, the wall is first reduced by cold rolling to obtain large deformation, and then a variety of gauges are obtained by cold drawing lattice.


Post time: Nov-23-2020