RU1801639C - Method of pilger rolling of tubes - Google Patents

Abstract

Usage: in the production of mountains of embossed pipes with pilgrim rolling. In the method of pilgrim rolling pipes, each supplied portion of the metal of the sleeve is deformed on the mandrel by pilgrim wolves having streams with a reducing, crimping and polishing sections, which form a gauge whose height on the polishing section is equal to the diameter of the pipe: When each portion of the metal of the sleeve is deformed, the handle is forced to move mandrel in the course of rollback of the sleeve by an amount greater than or equal to half the product of the amount of feed to the hood. Calibration of the pipe in the polishing section of the stream is carried out in caliber, the central parts of which are outlined with a radius equal to 1.04-1.06 of the radius of the pipe. As a result, the quality of alloy steel pipes and alloys with a high coefficient of linear expansion is improved by removing back pressure from the mandrel head during rolling. ate with

Description

The invention relates to pipe rolling production, and in particular to a method for rolling pipes, and can be used in the production of pipes in pipe rolling plants with pilgrim mills.

The aim of the invention is to improve the quality of alloy steel pipes and alloys with a high coefficient of linear expansion in pipe rolling plants with pilgrim mills,

This goal is achieved by the fact that during the deformation of each portion of the metal of the sleeve in the reducing section, the roll roll forces the mandrel to move along the rollback of the sleeve-pipe to

the value is greater than or equal to half the product of the feed rate, and the pipe is calibrated in the polishing section of the stream in caliber, the central parts of which are limited by a radius equal to 1.04-1.06 of the radius of the pipe.

Using the proposed method of pilgrim rolling pipes will improve the quality of pipes from alloyed ma. rock of steel and alloys with a high coefficient of linear expansion due to the task of the sleeve into the deformation zone with backing, and rolling without backing from the side of the mandrel head and ring, which eliminates runout and, accordingly, pointing out the difference.

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and the implementation of the Central part of the creep rolls in the polishing area equal to 1.04 - 1.06 of the radius of the pipe allows you to create a greater separation of metal from the mandrel from the outlets, which in turn creates a gap between the mandrel and the inner surface of the pipe, allowing free removal of the mandrel from the pipe .

The inventive method of pilgrim rolling pipes of alloyed steel grades and alloys with a high coefficient of linear expansion is characterized in that in order to improve the quality of alloy steel pipes and alloys during deformation of each portion of the sleeve metal in the reducing section, the roll handle forces the mandrel to be moved along the rollback of the sleeve-pipe by an amount greater than or equal to half the product of the feed to the hood, and the calibration of the pipe in the polishing section of the stream is carried out in caliber, the central parts and which is limited by a radius equal to 1.04 - 1.06 of the radius of the pipe ..

At the initial moment of deformation (rolling), the sleeve is reduced, i.e., there is no contact between the inner surface of the sleeve and the mandrel, then there is compression on the wall and further calibration in the polishing area. After 90 ° pitching, the contacting part of the metal with the dorne enters the discharge points and at the initial moment of the next deformation cycle, the metal detaches around the entire circumference of the mandrel, which allows the mandrel to be removed from the sleeve by creating pressure in the front cavities of the forgoller hydraulic cylinders. The execution of the Central part of the roll roll in the polishing area equal to 1.04 - 1.06 radius of the hot pipe allows you to create a large separation of the metal of the mandrel in the places of release and, accordingly, provides a greater gap between the mandrel and the pipe, eliminating the jamming of the mandrel in the pipe, and increases the time during reduction required to remove the mandrel from the sleeve-tube for each reduction cycle.

This method was tested on a pipe rolling unit with a pilgrim mill 8-16 ChTPZ in the production of nickel-based alloy pipes (KhN78T) with a size of 360x70 mm.

Pipe manufacturing technologies are as follows:

1) Heating of a centrifugally cast billet with a size of 530 x 235 x 3600 mm in a methodical furnace;

2) Rolling the billet on a pilgrim mill with a caliber of 382 mm rolls into tubes 365 x 71 mm in size (in hot condition) according to the proposed method.

Using the proposed method, it was possible to obtain pipes made of an XH78T nickel-based alloy with a high coefficient of linear expansion in a plant with pilgrim mills.

The use of pipes made of KhN78T alloy in the construction of domestic reactors for the production of carbon tetrachloride in exchange for import supplies will make it possible to obtain an economic effect,

Claims (1)

SUMMARY OF THE INVENTION A method for pilgrim rolling pipes, comprising batch feeding and deforming each portion of metal of a sleeve on a mandrel with pilgrim rollers having each stream with reducing, crimping, and polishing sections along the circumference that form a gauge whose height in the polishing section is equal to the diameter of a hot pipe, characterized in that, in order to improve the quality of alloy steel pipes and alloys, during deformation of each portion of the metal of the sleeve in the reducing section, the roll brook forces the mandrel is moved along the rollback of the sleeve by an amount greater than or equal to half the product of the feed rate, and the pipe is calibrated in the polishing section of the handle in caliber, the central parts of which are limited by a radius equal to 1.04 - 1.06 of the radius of the pipe .