SU902886A1

SU902886A1 - Tube forming mill

Info

Publication number: SU902886A1
Application number: SU792857532A
Authority: SU
Inventors: Виктор Андреевич Рымов; Иван Николаевич Потапов; Владимир Васильевич Горбунов; Сергей Владимирович Самусев; Виктор Владимирович Булатов; Александр Михайлович Фадеев; Павел Максимович Гаврилин; Евгений Маркович Кричевский; Валерий Петрович Орлов
Original assignee: Московский Ордена Трудового Красного Знамени Институт Стали И Сплавов
Priority date: 1979-12-25
Filing date: 1979-12-25
Publication date: 1982-02-07

Description

(54) ТРУБОФОРМОВОЧНЫЙ СТАН(54) TUBE FORMING MILL

Изобретение относитс к производству электросварных пр мошовных труб, а точнее к конструкции трубоформовочных станов.The invention relates to the production of electric-welded straight pipes, and more specifically to the design of pipe mills.

Изобретение наиболее эффективно может быть использовано при реконструкции существующих трубосварочных агрегатов и при проектировании новых станов дл производства на них труб любого сортамента .The invention can most effectively be used in the reconstruction of existing pipe-welding units and in the design of new mills for the production of pipes of any grades on them.

Известен трубоформовочный стан, содержащий р д последовательно установленных формовочных клетей с чередующимис парами горизонтальных приводных и вертикальных холостых валков, образующих открытые и закрытые калибры 1.A pipe-forming mill is known, comprising a series of sequentially installed forming stands with alternating pairs of horizontal drive and vertical idle rolls forming open and closed gauges 1.

В известном стане профиль рабочих поверхностей валков открытых калибров выполнен двум радиусами.In a known mill, the profile of the working surfaces of the rolls of open gauges is made with two radii.

Преимуществоуказанного трубоформовочного стана заключаетс в том, что полоса при смещении в сторону должна разогнутьс с одной стороны и согнутьс с другой, т. е. должна получить дополнительную деформацию. Таким образом, устойчивость полосы в данном калибре значительно выще, чем в однорадиусной.The advantage of the pipe mill shown is that the strip, when shifted to the side, should be unbent from one side and bend from the other, i.e., should receive additional deformation. Thus, the stability of the band in this caliber is much higher than in single-radius.

Недостаток этого трубоформовочного стана заключаетс в том, что в результате даже незначительного смещени полосы (щтрипса) в первых открытых калибрах нарушаетс симметри формовки, котора вл етс одним из основных факторов, определ ющих качественную формовку трубной заготовки. Смещение полосы, например, вследствие ее сабельности или коробоватости при входе в первый открытый калибр приводит к выформовке периферийных участков с различным радиусом, выравнивание которых в других открытых калибрах не предусмотрено. Закрытые калибры стана уменьшают эту разницу, однако она сохран етс и приводит к смещению кромок при сварке. В процессе сн ти грата вместе с ним подрезаетс одна из кромок и, следовательно, ослабл етс сечение трубы.The disadvantage of this pipe forming mill is that as a result of even a slight shift of the strip (shtripsa) in the first open calibers, the symmetry of the molding is broken, which is one of the main factors determining the quality forming of the tubular billet. The shift of the strip, for example, due to its sagacity or warping at the entrance to the first open gauge leads to the formation of peripheral areas with different radii, the alignment of which in other open calibers is not provided. The closed calibers of the mill reduce this difference, however, it remains and leads to a displacement of the edges during welding. In the deburring process, one of the edges is cut along with it and, consequently, the pipe section is weakened.

Claims

The closest technical solution to the invention is a pipe forming mill containing a series of sequentially installed molding stands with alternating pairs of horizontal drive and vertical idle rolls forming open and closed gauges 2. In this mill, the profile of the working surface of the open gauge rolls is made in one radius. The disadvantage of this mill is that in open gauges the strip in the contact zone between the lower and upper rollers has a constant radius of curvature along its width. Such forms of the profile of open gauges hold the strip in the position necessary for high-quality welding of the tube billet with minor component forces that do not coincide in direction with the forming axis and arise from various tuning defects, strip sickle, etc. However, when the resultant component of the above factors is reached, a certain "extreme size" rolls do not significantly impede the shift of the strip in the transverse direction. This is due to the fact that in an open single-caliber caliber, only the frictional force between the strip and the forming rolls prevents the strip from shifting. Thus, the strip shift is determined by the ratio of the friction force and the transverse component of the extreme force. The shift of the strip in the open one-radius calibers of the pipe forming mill is somewhat corrected in closed and welding calibers, but with a significant amount of shift the stress-strain state of the tube billet is significantly different from the stress-strain state with a symmetrical bending process. This causes a redistribution of residual stresses in the billet relative to the vertical axis, which, in turn, can lead to a spiral twisting of the strip and complicate the welding of the tubular billet. The aim of the invention is to improve the quality of forming the tubular billet by reducing the transverse displacement of the strip in the first along the forming cages of the pipe forming mill. The goal is achieved by the fact that in a pipe forming mill containing a series of sequential molding stands with alternating pairs of horizontal drive and vertical hollow rolls forming open and closed gauges, at least one pair of rolls forming the open gauge is made with a working surface profile in the form of a parabola. Such an embodiment of the working surface of the rolls allows an increase in the transverse rigidity of the billet, since the shift, GU of the strip in the open caliber formed by parabolic surfaces prevents not only the friction force between the working surfaces of the rolls and the strip, but also the resistance of the strip itself to the shaping of the strip on its width. This is due to the fact that each point of the surface of the forming strip has its own radius of curvature, which varies monotonically from the R-radius of curvature of the center point to R, the radius of curvature of the edge of the strip. To calculate the parameters of the proposed gauge, you can use the equation:. where a is the coefficient allowing the open caliber parameters to be changed. FIG. 1 shows a pipe forming mill; in fig. 2 shows section A-A in FIG. 1. The pipe forming mill contains a number of forming stands with horizontal drive and vertical idle rolls, forming open gauges in cages x 1-3, and closed gauges in cages x 4-6. Horizontal rolls 7 and 8 of the cage 1 are made with the profile of the working surface in the form of a parabola. The camp works as follows. The strip (strip) enters the forming line and, in the process of movement, in the forming cages gradually bends to a closed billet. The proposed pipe forming mill, in comparison with the best examples of known similar devices, allows reducing the transverse displacement of the strip in the first rolls along the forming to improve the quality of forming the tubing. blanks. An invention of a pipe forming mill comprising a series of sequentially installed molding stands with alternating pairs of horizontal drive and vertical idle rolls forming open and closed gauges, characterized in that, in order to improve the quality of forming a tubular billet by reducing the lateral displacement of the strip during the first forming process The cages, at least one pair of rolls forming an open gauge, are made with a profile of the working surface in the form of a parabola. Sources of information taken into account in the examination 1. Yu. M. Matveyev, et al. Calibration of rolls and toolpipes of pipe mills. M., “Metallurgizdat, 1951, p. 438.

2. In the same place 436 (prototype).

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