RU2346766C2 - Method of pilger rolling - Google Patents

Abstract

FIELD: technological processes; metallurgy.

SUBSTANCE: method of pilger rolling includes insertion of drift bolt, having section with higher taper, in cartridge under drift bolt head for alignment of cartridge back end, and its deformation by rolls with alternate profile of caliber, at that taper ring is additionally put on drift bolt, and its taper part is used to align cartridge front end relative to drift bolt axis.

EFFECT: reduction of priming time, transverse thickness variation of pipe front ends and reduction of metal consumption coefficient.

Description

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

There is a method of pilgrim rolling, where a mandrel is introduced into the sleeve by a feeding apparatus, on which it is rolled into a tube between two rolls rotating in different directions with a variable-gauge caliber (F.A. Danilov and other Hot rolling pipes. Metallurgizdat, 1962, p. 282 )

The disadvantage of this method is the increased difference in the front (seed) ends associated with the presence of a gap between the inner diameter of the sleeve and the diameter of the mandrel in the absence of centering of the sleeve is relatively mandrel. In addition, this method is accompanied by an increased seed time due to the lack of a tilting of the sleeve until the contact of the sleeve and the mandrel and an increased trimming of the seed end.

A known method of rolling a sleeve with a pre-pressed front end under the diameter of the mandrel, having a section with increased taper under the mandrel head (Steel, 2006, No. 9, p. 74).

The disadvantage of this method is that the rolling of pre-prepared sleeves with a compressed front end on the rolling device installed in the line of the piercing mill does not ensure the rhythm of rolling on the pilgrim mill, because the sleeves after flashing are not perfectly straight and the compressed end of the sleeve makes it difficult to insert the mandrel into the sleeve. In addition, it is structurally difficult to install a run-in device for crimping the front ends of the liners in the line of existing piercing mills in installations with pilgrim mills.

The objective of the invention is to reduce the lateral difference in the front ends of the pipes and to reduce the expenditure coefficient of the metal.

The technical result is achieved by the fact that in the known method of pilgrim rolling, including introducing into the sleeve of the mandrel, having a section with increased taper under the mandrel head to center the rear end of the sleeve, and deforming it with rolls with a variable caliber profile, the cone ring and its conical are additionally put on the mandrel part center the front end of the sleeve relative to the axis of the mandrel.

Comparative analysis with the prototype shows that the inventive method of pilgrim rolling is characterized in that after the mandrel is inserted into the sleeve, a conical ring is additionally put on the mandrel and its front end is centered on the mandrel with respect to the axis of the mandrel. Thus, the inventive method of pilgrim rolling meets the criterion of "Inventive step".

Comparison of the proposed method of pilgrim rolling not only with the prototype, but also with other technical solutions in the art did not reveal signs that distinguish the claimed method of pilgrim rolling from the prototype, which meets the criteria of patentability "Inventive step".

The method of pilgrim rolling is as follows. After the mandrel is inserted into the sleeve, the ring is tapered towards the sleeve at the front end of the mandrel, the mandrel is lowered onto the raised gate and the feeding of the feeding apparatus during rolling is clamped between the two cones. Those. when rolling the sleeve is centered relatively mandrel. When priming, the sleeve is tilted after each feed, while the longitudinal drawing along the entire perimeter of the front end will be equal, because the conical ring aligns the longitudinal flow of the metal, which eliminates the pointing of the difference and, accordingly, allows to reduce the trim from the front end. With the steady-state rolling process of the centered sleeve on the mandrel, guidance of the difference in the pipes is excluded.

The method of pilgrim rolling was tested at TPA 8-16 "OAO" ChTPZ "when rolling boiler pipes of 426 × 24 mm in size from a workpiece in the size of 600 × 100 × 1630 mm of steel grade 15X1M1F.

A sleeve measuring 610 × 415 in. × 2750 mm, worn on a mandrel with a diameter of 381/382 mm, was fixed with a conical ring measuring 437 × 387 in. × 150 mm (taper angle -9 ° 27 ') due to its stop in a raised gate, followed by moving the feed unit. Seeding of the front end on the conical ring takes place in 14 s compared to the usual 28-34 s, while the metal flow passed uniformly along the entire perimeter of the pipe. The cutting edge of the front end decreased ≈190 mm, i.e. 45 kg for rolling one workpiece.

Using the proposed method of pilgrim rolling will reduce the seed time, the lateral difference in the front ends of the pipes and reduce the expenditure coefficient of the metal.

Claims (1)

A method of pilgrim rolling, comprising inserting a mandrel into a sleeve having a section with a taper under the mandrel head to center the rear end of the sleeve, and deforming the sleeve with rolls with a variable caliber profile, characterized in that after inserting the mandrel into the sleeve, a conical ring is inserted onto the mandrel, the conical part of which center the front end of the sleeve relative to the axis of the mandrel.