CS224767B1 - Method of seamless tubes' widening and equipment for making same - Google Patents

Description

224 787

BACKGROUND OF THE INVENTION The present invention relates to a method for spreading seamless pipes from a slab and to an apparatus for carrying out the method.

Seamless expanded tubes are manufactured on expansion stands from a semi-finished product - billet. The billet is expanded by rolling the wall between the conical surface of the expanding mandrel and the two expanding disks. In the vertical plane, the extension is defined by extension rulers, the upper of which is adjustable and the lower is fixed.

The disadvantage of accompanying the production of seamless expanded pipes in this way and the device are helical irregularities on the outer and inner surfaces. Unevenness on the outer surface is decisively influenced by the extension rulers between which the pipe rotates. Unevenness of the inner surface is caused by bruises from the extension mandrel.

The disadvantages are eliminated by the method of spreading seamless pipes from billets and the apparatus for carrying out the method on the expansion stand consisting essentially of expanding the billet by rolling the billet wall to a final thickness by pressing the conical circumference of the expansion disks against the corresponding cone circumference of the expanding mandrel. wherein the walls of the already expanded tube are smoothed by pressing the smoothing rollers against the cylindrical portion of the expansion mandrel.

The essence of the apparatus for carrying out this method is that the extension discs are offset by 60 to 80 mm (one above and the other below the axis) in a vertical plane relative to the axis of extension from A and with smoothing rolls having a body diameter of 0.5 to 0.8 diameter of the expanding mandrel, which are mounted above and below the cylindrical portion of the expanding mandrel, in plan view with axes parallel to the axis of expansion of the tube and in plan view with axes inclined to each other by an angle of 4 to 7 °. The height of the polishing rollers is adjustable in

- 2,224,787 in a vertical plane with respect to the axis of the pipe to be expanded. The smoothing rollers can be provided with a smoothing surface in the form of a cylinder or hyperboloid.

By the method according to the invention, the billet tube is expanded continuously and smoothness of the outer and inner surface of the expanded tube is achieved, since the adjustment of the oblique angle between the two smoothing rollers aids the forward movement of the expanded tube. By adjusting the upper smoothing roller in a vertical plane, the necessary pressure is exerted between the upper and lower guide rollers, thereby determining the degree of rolling and smoothing the wall of the pipe to be expanded on both sides.

The following is an example of a particular use and apparatus according to the invention. Giant. 1 is a plan view of the device in cross-sectional view of the expanded tube in a plane passing through the axis of the expanded tube. Giant. 2 shows a side view without the expansion discs, but with both the smoothing rollers and the cross-section of the tube.

In this view, one extension wheel exceeds the axis of expansion (tube axis) by 60 to 80 mm, the other is reduced by the same value compared to the axis of expansion.

⁰ 2 reads wars diameter 328 mm and wall thickness of 13 mm určenýk manufacture pipes 2530 mm and a wall thickness, mm is pressed against the mandrel 2 rozáiřovacímu inclined leading section an extending disc 15 ° 1_ with the rotational axis inclined at an angle of 230 °. The axes of rotation of the polishing rollers 2 and 6 form an angle of 5 ° to each other. Expansion mill with smoothing rollers 2 and 6, consisting essentially of expansion discs 2 »whose axes of rotation are inclined to the axis of the tube 2 by an angle α, with the surface lines of the working surface of the wheels 2 forming an angle cf and the surface lines of the conical portion of the expanding mandrel 2 form an angle rf with the axis of the expanding tube, wherein above and below the cylindrical portion of the expanding mandrel 2 are smoothing rolls 1 and 6b by axes of rotation deviating from each other by an angle. The height of one or both of the smoothing rolls 2 ^{and 3} and adjustable in a vertical plane relative to the axis of the pipe to be expanded 2 ·

Claims (4)

-3 P S E D Μ E T OF THE INVENTION 224 7Β7 A method for spreading seamless tubes and apparatus for carrying out the method, from a billet to an expansion stand with expansion discs, characterized in that the billet is expanded by rolling the billet wall to a final thickness by pressing the cone circumference of the expansion disks onto the expanded tube wall against wherein the walls of the already expanded tube are smoothed by pressing the smoothing rollers against the cylindrical portion of the expansion mandrel. 2. Apparatus for carrying out the method according to claim 1 with expansion discs, characterized in that the expansion discs (1) are deviated by 60 to 80 mm in a vertical plane from the expansion axis and with smoothing rollers (5) and (6), the body diameter of which forms 0.5 to 0.8 of the diameter of the expanding mandrel (2) mounted above and below the cylindrical portion of the expanding mandrel (2), in a front view with axes parallel to the axis of the expanding tube (3) and in plan view with axes inclined relative to each other angle 4 to 7 °, Device for carrying out the method according to claim 1, characterized in that the height of the polishing rollers (5) and (6) is adjustable in a vertical plane with respect to the axis of the pipe to be expanded (3). Device for carrying out the method according to side 1, characterized in that the smoothing rolls (5) and (6) are designed with a smoothing surface in the form of a cylinder or a hyperboloid. 1 drawing