SU38927A1 - A method of making rolled tubes with internal wall thickenings at the ends - Google Patents

Description

The main patent number 38516 describes a method for producing pipes with internal wall thickenings at the ends of a blank provided with an annular constriction by means of a pilgrim rolling process and a mandrel with a ledge; This method consists in rolling the tubular billet on the core that abuts the step into the annular constriction in such a way that before the location of the shoulder of the core of the gripping action of the rolls is removed, the material can be pulled back.

The present invention is applied to the manufacture of pipes having not only thickened ends, but also local thickenings extending through the middle part of the pipe, known from patent number 38516 of the method. Such pipes are used, for example, in the form of columns, as well as in all those cases where a pipe with a smooth cylindrical (377)

to ensure its strength or for some other reason, it must have a thickened cross section in certain places. In addition, this method can also be applied to the production of casing with internal thickening of the walls at the ends, not only for pipes of ordinary length, but also twice the length and more. The application of the proposed method for such purposes will significantly improve the productivity of the rolling mill and reduce the amount of material waste, so that it is possible to significantly reduce the cost of pipe production, etc.

According to the invention, a method for manufacturing pipes with localized bulges extending within the middle part is that the tubular billet is flared up to a place with an internal bulge into pieces

a mandrel having a normal diameter; then, the workpiece is fixed on the mandrel in such a position that the material necessary for making the bulge is against the shoulder of the mandrel; near which -and flaring of the bulge is made.

To fasten the workpiece on the mandrel, when expanding the thickening, a banded portion is applied to the free part of the length of the part of the mandrel having a normal thickness, so that its ends rest on its support and auxiliary rings. After expanding the thickening, the cover portion is removed to allow free expansion of the subsequent normal cross-section of the pipe. The part of the mandrel, having a normal thickness, remains free, and the processed product with the obtained thickening is adjacent to the part of the mandrel that has a ledge, and therefore it can be assumed that for perfect rolling of the place where the mandrel has a ledge, it is necessary that the material move the flaring of the transitional part from the thick-walled cross-section of the pipe to the thin-walled one.

In FIG. 1 shows a tube with internal thickening; FIG. la cross-section along the line V – V in FIG. Ij of FIG. 2 - tube after receiving a local internal thickening at the end; FIG. 3 - the pipe subjected to the final flaring.

The tubular billet a processed (Fig. 1) is provided at its front end with an internal thickening and flared in the middle part for a certain length to a normal cross section of the pipe. The workpiece is machined to obtain an internal local thickening at the required place of the pipe is positioned with respect to the mandrel in such a position that the material necessary for making the thickening is above that part b

mandrel, which has a ledge. This installation is obtained by placing the cover part d over the free length of that part of the mandrel, which is of normal thickness, with the cover part d on one side resting on the stop ring e, and on the other side on the auxiliary ring.

To flare a portion of the pipe with a normal cross-section and adjacent to the thickening, the cover portion d is removed (Fig. 2). During the flaring of the transitional part, the product fits with its previously obtained thickening to the transitional part g of the mandrel, and can move back to the moment when the rings and /, as shown in FIG. 3, will come in contact with each other. The further process of expanding the pipe (Fig. 3) is carried out according to the method described in patent number 38516, so that an internal thickening at the end of the pipe is obtained.

In addition to the internal thickening of the pipe ends, the proposed method provides for not only one such local thickening, but also any number of such thickened ledges.

Subject patent a.

1. A variation of the method according to claim 2 of patent No. 38516 for the case of making a thickening in the middle parts of a pipe, characterized in that, to a place with an internal thickening, the expansion of the product is performed on a part of the mandrel having a normal diameter, after which the pipe is fixed on the mandrel and in in such a position that the material necessary for the manufacture of the bulge is against the shoulder of the mandrel and the bulge is flared.

2. A device for carrying out the method according to claim T, characterized in that in order to fix the product on the mandrel, a cover portion d is applied, superimposed on the free length of that part of the mandrel, which has a normal diameter.

to the dependent patent of the in-ing company Acts. island of united food plants № 38927

/, e

 L.

yy ..:,

Have

s4zig. one

ig. 1a

s4zig.2

f y A

f S ACI,

Ess.jsdgg C, - (, --.-- Lig. I