RU2350417C1 - Method of shaped tube production - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: cold rolling of pipes is implemented with drawing out µ=1.5-1.6, single-pass drawing of round pipe without internal tool, is implemented with drawing out µ=1.15-1.17, and single-pass drawing of round pipe through profile ring is implemented with clamping by wall with minimal section, equal to 3.0-3.5 mm with underspeed not more 10 m/min on floating plug mandrel, length of tapered part of pipe exceed length of conical part of profile ring.

EFFECT: pipes with high-precision external hexahedral profile and internal hole with minimal discharge coefficient of defined metal and with efficient production.

Description

The invention relates to pipe production, in particular to the production of seamless pipes by cold deformation, namely the production of pipes with an external hexagon and an inner round hole.

A known method of manufacturing a profile pipe with an external hexagon and an inner round hole on a roller mill for longitudinal rolling of pipes (CPTR). [Danchenko V.N. and other "Production of shaped pipes" / M., "Intermet Engineering", 2003, p.151-152].

The disadvantage of this method is its low productivity (up to 300 running meters per shift), determined by the technical capabilities of the mills.

Also known is a method of manufacturing profile pipes with an external hexagon and an inner circular hole with multi-pass drawing without a mandrel through profile rings [A. Shurupov AK, Freiberg MA “Production of pipes of economical profiles” // Sverdlovsk, Metallurgizdat, 1963, p. 88].

The disadvantage of this known method is that the resulting pipe hole will not be a circle, but only a hexagon approaching the circle.

The closest in their technical essence and the achieved results to the proposed invention is the drawing of a round pipe without a mandrel and the subsequent drawing of a round pipe in the last one or two passes on the mandrel through the profile rings [Shurupov AK, Freiberg MA “Production of pipes of economical profiles” // Sverdlovsk, Metallurgizdat, 1963, p. 88].

The disadvantage of the prototype method is the remaining initial difference after dragging the pipe without a mandrel, which, with subsequent profiling, leads to the appearance of traces of non-working on its inner surface in places of minimal deformation.

The technical problem solved by the invention is to obtain a pipe with a high-precision external hexagonal profile and internal hole with minimum flow rates of the given metal and with high productivity.

The solution to the technical problem is achieved by the fact that in the method for manufacturing profile pipes, including cold rolling of pipes, single-pass drawing of a round pipe without a mandrel and single-pass drawing of a round pipe on a mandrel through a profile ring, while cold rolling of pipes is carried out with an extractor µ = 1.5-1 6, a single-pass drawing of a round pipe without a mandrel is carried out with a hood µ = 1.15-1.17, and a single-pass drawing of a round pipe through a profile ring is carried out with compression along the wall in a minimum section equal to 3.0-3.5 mm, with reduced speed e more than 10 m / min, the self-setting on the mandrel, the length of tapered portions of which exceeds the length of the conical part of the profile ring.

The process of manufacturing a profile pipe is as follows.

The prepared tubular billet is rolled on a cold pipe rolling mill with an extract µ = 1.5-1.6 into a thick-walled tube with a ratio S / D = 0.12-0.14, where S is the pipe wall thickness, mm; D is the outer diameter of the pipe, mm.

Разностенность большей величины приводит к неполному оформлению профиля шестигранной трубы и образованию на внутренней поверхности трубы следов в виде рисок, выводящих размеры внутреннего диаметра за пределы допусков.Cold rolling of pipes allows you to get a pipe with a difference:

The difference of a larger value leads to an incomplete design of the profile of the hexagonal pipe and the formation of traces in the form of marks on the inner surface of the pipe, displaying the dimensions of the internal diameter beyond the tolerances.

Next, a single-pass drawing of a round pipe without a mandrel with a hood µ = 1.15-1.17 is carried out, which ensures the preparation of the required dimensions for drawing the profile pipe while maintaining the required dimensional accuracy.

Due to the fact that single-pass drawing to the finished size on the self-aligning mandrel through the profile ring occurs with compression along the wall in a minimum section equal to 3.0-3.5 mm, drawing is carried out at a reduced speed of not more than 10 m / min, which allows get the desired profile without overheating of the metal and the formation of flaws.

The drawing of thick-walled pipes is also associated with the formation of a developed zone of non-contact deformation extending beyond the end plane of the profile ring. Therefore, to prevent the onset of deformation on the barrel of the self-aligning mandrel, the length of its conical part is made longer than the length of the conical part of the profile ring.

The analysis of the prior art by the applicant, including a search by patent and scientific and technical sources of information and identification of sources containing information about analogues of the claimed invention, allowed to establish that the applicant did not find a source characterized by signs identical to all the essential features of the claimed invention. The definition from the list of identified analogues of the prototype as the closest in the totality of the features of the analogue allowed us to establish a set of essential distinguishing features in relation to the technical result perceived by the applicant in the claimed method set forth in the claims.

Therefore, the claimed invention meets the condition of "novelty."

In the study of other well-known technical solutions in this technical field, signs that distinguish the claimed solution from the prototype were not identified. Therefore, the claimed invention meets the condition of "inventive step".

внутренний диаметр -

The method is tested and implemented in an industrial environment. A batch of profile pipes was manufactured in an amount of 6342 m, 46 _bx × 32 _goth in size, from steel 35 according to TT 161-662-2000 “Steel seamless pipes with an external hexagon and a round internal cross-section profile”. In accordance with the requirements of TT 161-662-2000, pipes must have dimensions: hexagon -

inner diameter -

In fact, the following dimensions were obtained:

внутренний диаметр -

hexagon -

inner diameter -

The yield was 100% with a consumption ratio of 1.05.

Using the proposed method will allow to master the production of shaped pipes with an external hexagon and an inner round hole in accordance with the requirements of TT 161-662-2000 with a flow coefficient from the start of the metal of 1.05-1.09.

Claims (1)

A method of manufacturing profile pipes, including cold rolling of pipes, single-pass drawing of a round pipe without a mandrel and single-pass drawing of a round pipe on a mandrel through a profile ring, characterized in that cold rolling of pipes is carried out with an extractor µ = 1.5-1.6, single-pass drawing of a round pipes without a mandrel are carried out with an exhaust hood µ = 1.15-1.17, and a single-pass drawing of a round pipe through a profile ring is carried out with compression along the wall in a minimum section equal to 3.0-3.5 mm, at a reduced speed of not more than 10 m / min on self-adjusting Xia mandrel cone part whose length exceeds the length of the conical part of the profile ring.