RU2463124C2 - Method of making tubular articles with external and internal bulges - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and may be used in aircraft and rocket engineering for making high-strength shells connected by lengthwise and transverse ribs. Hollow cylindrical billet is fitted on grooved mandrel against the stop, said mandrel being fitted on rod to displace unobstructed thereon, and formed by rolls to squeeze pattern. After forming first bulge, said mandrel is displaced synchronously with rolled billet.

EFFECT: higher precision of finished articles.

4 dwg

Description

The invention relates to the field of metal forming, and more specifically to a method for manufacturing tubular products with external and internal thickenings. Most effectively, the invention can be used in the aviation and rocket industries to create high-strength shells connected by longitudinal and transverse ribs.

A known method of manufacturing a pipe product with thickenings, see German patents No. 518991, class. B21H 8/00 claimed 02/09/30, publ. March 19, 31; No. 627323 class. B21H 8/00 claimed 11/05/31, publ. 03/13/36 g.

The known method includes feeding a hollow cylindrical billet to the mandrel all the way to the sleeve, rolling the workpiece at a reduced diameter of the mandrel with grooves to the required length according to the compression scheme, retracting the thrust sleeve and further rolling the workpiece according to the tensile scheme over the larger diameter of the workpiece. After rolling the required length, the mandrel is reduced in diameter to the deformation zone, the thrust sleeve is brought in and the process continues according to the compression scheme. The mandrel is rigidly connected to the shaft.

The disadvantage of this method is the lack of accuracy of the obtained products, since when rolling on a workpiece of internal thickenings after filling the first groove on the mandrel, further rolling leads to a cut of the internal thickening or "swelling" of this place on the outer surface of the workpiece. The mandrel is pressed through by the mandrel, since the mandrel is rigidly connected to the rod.

Of the known methods for manufacturing tubular products with external and internal thickenings, the closest in technical essence is the method used in the construction of the mill and described in the patent of the Russian Federation No. 2039617, cl. B21H 8/00 claimed 10/01/93, publ. 07/20/95

This method of manufacturing tubular products with external and internal thickenings involves rolling a hollow cylindrical workpiece on a mandrel with grooves. The mandrel is made in one piece with the rod. The billet is fed to the mandrel all the way to the sleeve, the billet is rolled by rolls according to the compression scheme on the smaller diameter of the mandrel to obtain an internal thickening, then the thrust sleeve is retracted and rolling is carried out on the mandrel with a large diameter according to the tensile pattern. Thickening on the outer diameter of the workpiece is obtained due to information-breeding rolls.

The disadvantage of this method is the lack of accuracy of the obtained products, since when rolling the workpiece according to the tensile pattern, incomplete filling of the grooves on the mandrel occurs. If in the known method the rolling of the workpiece is carried out according to the compression scheme, then, after filling the first groove on the mandrel, further rolling leads to a cut of the internal thickening or “swelling” on the outer surface of the workpiece, since the rolling is carried out on a mandrel rigidly connected to the rod and not having the ability to move freely with a rolled billet, additionally captured by internal thickenings.

The objective of the present invention is to provide a method for the manufacture of tubular products with external and internal thickenings, which allows to increase the accuracy of the resulting products by changing the rolling pattern.

The task is achieved by a method of manufacturing tubular products with external and internal thickenings, including feeding to the stop a hollow cylindrical billet on a mandrel with grooves mounted on the rod with the possibility of free movement along it, and rolling it by rolls according to the compression scheme, and after rolling the first thickening, the mandrel is moved synchronously with the rolled stock.

In addition, when rolling internal thickenings on a mandrel with deep grooves, an axial force is applied to the mandrel in the direction opposite to its movement.

This embodiment of the method of manufacturing tubular products with external and internal thickenings will improve the accuracy of the rolled products.

This is achieved by the fact that during the rolling of internal thickenings on a mandrel with grooves, the workpiece is deformed according to the compression scheme on a freely movable mandrel, as a result of which the grooves are completely filled with metal. The mandrel is mounted on the rod with the ability to move along it, therefore, after rolling the first internal thickening, it moves synchronously with the rolled billet, just as it does when rolling according to the tension scheme, although rolling is carried out according to the compression scheme. The mandrel can be moved relative to the rod due to the transfer of axial force arising after filling the first groove and further metal drawing, that is, the rolling process self-adjusts the feed speed of the mandrel at any given moment. On flat sections of the mandrel, its speed is maximum, and over the grooves, as they are filled, the speed decreases.

To explain the invention, an example of the method is described below with reference to the accompanying drawings, in which:

figure 1 shows a method of manufacturing tubular products with external and internal thickenings, rolling on a smooth section of the mandrel;

figure 2 is the same, the rolling of the first internal thickening;

figure 3 is the same, rolling subsequent internal and external thickenings;

figure 4 - pipe manufactured by the proposed method.

A method of manufacturing a pipe product with external and internal thickenings is as follows.

A hollow cylindrical billet 1 is put on the mandrel 2 with grooves 3, moved to the stop 4 and rolled by rollers 5 according to the compression scheme. The mandrel 2 is mounted on the rod 6 with the possibility of free movement. When rolling on a smooth section of the mandrel 2, the workpiece 1 is extended, and the metal, sliding along the mandrel, moves with the speed of the feed mechanism of the mill, increased by the speed of elongation of the workpiece (figure 1). To obtain internal thickenings, the rolling of the cylindrical billet 1 is carried out by rolls 5 according to the compression scheme on the mandrel 2 with grooves that can freely move along the rod 6. After rolling the first internal thickening (Fig. 2), the rolled metal ceases to slide along the mandrel 2 and carries it along , that is, the mandrel moves synchronously with a speed greater than the feed rate by the amount of metal drawing speed. In this case, rolling is carried out according to the compression scheme, and sliding friction along the mandrel is the same as according to the tensile scheme. Thickening on the outer diameter of the product is obtained by mixing and breeding rolls 5.

When rolling a cylindrical workpiece on a mandrel with deep grooves, a certain axial force is applied to the mandrel in the direction opposite to its movement to increase the compression force, which leads to a more complete filling of the deep grooves on the mandrel, thereby expanding the technological capabilities of the deformation process. For example, with a thin wall of the initial billet, it is possible to fill deep grooves only with the application of axial force to the mandrel.

To prevent slipping of the workpiece on the mandrel, the mandrel can be installed on the drive rod by means of dowels or splines, which will improve the quality of the rolled products.

An example of a specific implementation of the method of manufacturing pipe products with external and internal thickenings.

On a ⌀140 mm mandrel 80 mm long, having six transverse radius grooves made from 2 to 5 mm wide and 4 mm deep, and 14 diametrical longitudinal rectangular grooves 4 mm deep and 3 to 6 mm wide, a turned-in cylindrical workpiece ⌀160 was put on mm, 40 mm long and internal внутрен140.5 mm from aluminum alloy (AMG). The mandrel with the workpiece is mounted on a ⌀60 mm shaft. The rotation to the workpiece was transmitted from the ring stop. Rolling was carried out according to the compression scheme. During rolling, the mandrel moved along the rod synchronously with the rolled product. The product was rolled at n = 80 rpm, s = 1 mm / rev with 50% wall compression, where n is the number of turns of the workpiece, s is the feed of the workpiece per 1 revolution. After rolling, the inner surface of the product corresponded to the outer surface of the mandrel. External thickenings were obtained by mixing-breeding rolls.

The proposed method for the manufacture of tubular products with external and internal thickenings in comparison with the known allows to increase the accuracy of the resulting products.

Claims (2)

1. A method of manufacturing tubular products with external and internal thickenings, including feeding to the stop a hollow cylindrical billet on a mandrel with grooves mounted on the rod with the possibility of free movement along it, and rolling it by rolls according to the compression scheme, and after rolling the first thickening, the mandrel is moved synchronously with a rolled billet. 2. The method according to claim 1, characterized in that an axial force is applied to the mandrel in the direction opposite to its movement.

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