SU1113193A1 - Method of rolling tubes - Google Patents

Abstract

PIPE ROLLING METHOD, including the task of harvesting into rolls, deforming a part of the blank with rollers on a short mandrel, removing the blank with rolled short mandrel from the rolls, re-performing it with a short mandrel into rolls, deforming on an additional mandrel and pushing out a short mandrel of an additional one This is the reason why, in order to increase the yield of the right way to the production of sleeves by screw rolling from a solid billet, the sleeve with a short mandrel is re-set into rolls with the opposite end.

Description

The invention relates to pipe production and can be used in the production of hot-rolled pipes from carbon and highly alloyed steel and alloys. When rolling tubes, there are cases of mandrel rolling when it is necessary to stop the process and remove the billet from the mill. The reason for this may be the setting of the mill, but most often insufficient stability of the spout of the mandrel, especially when flashing hard and refractory steels and alloys. When flashing large ingots, the cause of the crimping of the mandrel is the presence of a shrinkage shell, penetration of which is accompanied by cutting of the axial velocity, loss of stability of the cross section of the liner and termination of the flashing process. In addition to the loss of productivity of the mill, the setting of mandrels leads to a partial or complete loss of metal and mandrels and accordingly increases the expenditure ratio. Sunset is most often occurring between the middle and the rear end of the workpiece, as well as when setting up the mill for a new assortment, when the rear end of the workpiece is overheated or underheated due to increased wear of the rolls, accompanied by an increase in axial slip, etc. The closest proposed is a method of rolling tubes, including the task of billet rolls, deformation of a part of the billet rolls on a short mandrel, removing the billet with rolled short mandrel from the rolls, re-task it with a short mandrel in the roll, deformation on an additional mandrel and pushing the short mandrel additional sp. The limestone method is designed for the longitudinal rolling of a hollow billet, when a billet with a short mandrel is re-set with the same end, and when meeting two mandrels are consistently placed in the pipe one after the other creating tension in the metal in the alignment zone, surrounding the process of rolling and ejecting the short mandrel at the end of rolling. However, when using a solid billet due to the design of a pierced mandrel, it is not possible to ensure reliable alignment of the additional mandrel short and ensure that the blank is docked. The purpose of the invention is to increase the yield in the production of shells by screw rolling from a solid billet. The goal is achieved in that according to the method of tube rolling, which includes the task of making blanks into rolls, deforming part of the workpiece with rolls on a short mandrel, removing a blank with rolled short mandrel from the rolls, re-performing it with a short mandrel into rolls, deforming it on an additional mandrel and pushing short mandrel additional, re-set the sleeve with a short mandrel in the rolls opposite end. The method allows to obtain a suitable sleeve from the blank, inside which the mandrel is rolled from one end, and to preserve it. The drawing shows the scheme of rolling pipes. The scheme contains the workpiece 1, the rolls 2, the additional mandrel 3, against which the rolled mandrel 4 is directed, Specify a solid workpiece in the rolls and subject it to deformation by the rolls on a short mandrel. If the short mandrel has been crimped, i.e., the process is interrupted, the workpiece is removed with the short mandrel rolled out of the rolls and set again into the rolls by the opposite end and deformed on an additional mandrel that pushes the short mandrel at the end of rolling. An ejected axial force acts on the rolled up short mandrel through the metal immediately after the billet is seized by the rolls, which is proportional to the pressure of the metal on the rolls and the sine of the angle of the input cone. Then, upon contact with the additional mandrel, an axial force is added to the buoyancy force from the mandrel. A flashing process thus exists while simultaneously rolling out the rolled up short mandrel. The sleeve is routed for further processing into the finished pipe, and the released mandrel can be used to flash subsequent billets (ingots).

31

The diameter of the secondary piercing mandrel is 1.01-1.20 of the diameter of the rolled up short mandrel. The lower limit of the diameter of the mandrel is determined by the condition of providing an excess of the frictional forces required for the ejection of the rolled-up short mandrel. As studies have shown, the stability of the flashing process with simultaneous ejection of the stitches of a short mandrel louse is provided in the case when the diameter of the additional mandrel is at least 1% larger than the diameter of the rolled short mandrel.

With a smaller diameter of the additional mandrel, the process proceeds unstably with the slipping of the workpiece in the mill rolls and the unstable release of the deformation zone.

The upper limit of the EB is selected from the condition that the transverse profile is stable in the output cone of the deformation zone.

The process can be conducted on an additional mandrel whose diameter is equal to the diameter of the rolled short mandrel, but with increased compression. However, the first way is preferable in order to better ensure a stable process flow.

Experienced rolling, carried out on a half-pierced mill, confirmed the advantage of the proposed method. If the workpiece is 50 mm

31934

With the opposite end of the liner with a 34 mm short mandrel rolled up, and deformed on a mandrel whose diameter was equal to or less than the diameter of the short mandrel rolled up, the extrusion process of the mandrel was unstable.

When the firmware was reinserted on the frames, when the diameter of the additional mandrel was taken larger than the diameter of the hardened short mandrel, the ejection of the rolled up short mandrel was stable. So with the installation of additional mandrels of size

34.6-37 mm, all blanks with rolled short mandrels were stitched, and the rolled mandrels were pushed out without disrupting the process.

0 In order to carry out the proposed method, the nsdokat billet is cooled completely; then it is cut to length. The stitched part of the sleeve heats up again and goes further

5 processing, the non-quenched part goes to remelting.

i

According to the proposed method, the operation and cooling and cutting operations are eliminated, and the Q billet is restored completely into the sleeve. The rolled up short mandrel is ejected and can be used to flash subsequent workpieces.

Claims (1)

METHOD FOR ROLLING PIPES, including the task of blanks in rolls, deformation of a part of the workpiece by rollers on a short mandrel, removing the blank with a rolled short mandrel from the rolls, its repeated task with a short mandrel in the rolls, deformation on an additional mandrel and pushing out a short mandrel additional, characterized in that , in order to increase the yield of a suitable production of sleeves by screw rolling from a continuous billet, re-define a sleeve with a short mandrel in the rolls with the opposite end. 1113193 2