SU1098604A1 - Method of forming semi-cylindrical pipe billets - Google Patents

Description

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Fig. 1 Invention relates to the production of welded pipes, and more specifically to the process of forming and welding pipes of finite length.

A known method for the production of welded pipes, in which the billet 5 is molded by an angle of.-More than a given, unbend to an angle less than the specified by an amount equal to the value of the spring, heat the edges with high-frequency currents and weld the billet U

into the tube Ci; J

The disadvantage of this method is the lack of dimensional stability both within one blank and from the blank 15 to the blank.

The closest to the invention to the technical essence is the method of forming semi-cylindrical billets, in which the workpiece is molded through an angle exceeding 180 ° with subsequent shaping up to an angle of 170-150 ° 23 ,,

The disadvantage of this method is that 25 there is no stability of the geometrical parameters of the workpiece at its ends and the middle part: the horizontal size between the edges (diameter) at the front and rear ends at 30-50 mm. less than in the middle part of the workpiece. The reason for this phenomenon is that when the end portions of the workpiece are unformed, one of its ends is free, i.e. harvesting

. 35 is cantilevered in the mill and takes place either at the rear end when unfolding the front end or at the front end when passing the rear end. When the middle part is unfolded, the workpiece is clamped by two crates, i.e. deformation patterns of the terminal and middle sections are different. And since the amount of opening for all sections of the workpiece is constant, the horizontal dimensions (between the edges) at the ends and in the middle part differ on the formed workpieces, which during the subsequent redistribution significantly reduces the quality of the end sections of the pipes and increases the length of 50 cut sections. ,

The purpose of the present invention is to improve the quality of pipes by reducing their geometric dimensions .. 55

The goal is to achieve that according to the method of forming round cylindrical billets, in which the workpiece is molded and the angle exceeding 180 °, with the subsequent unwrapping to an angle of 170-150, the unwrapping of the end sections on the length from the ends equal to 0.3-0, 7 dia-, {etra pipe, carried out to an angle of .65

Such an embodiment of the method makes it possible to stabilize the geometric dimensions and, thereby, to improve the quality of the pipes. This is achieved by the fact that as a result of different size of the forming on the end sections of length 0.3-0.7 of the pipe diameter from the end and on the central sections of the molded blanks (where the clamping conditions are different; the horizontal dimensions (between the edges) at the ends and in the middle the parts are the same, which, when redone, will affect the quality of the end sections of the pipes.

FIG. Figure 1 shows schematically a mill for carrying out the proposed method. general form; in fig. 2, section A-A in FIG. one; FIG. 3, section BB, FIG. one; Fig. 4 shows the arrangement of the shaping rollers during the shaping of the central part and the end sections.

The method of forming semi-cylindrical billets includes sorting according to mechanical properties and chemical composition, straightening sheets, gouging the longitudinal edges and chamfering, the task of the sheets in the rolls is an oriental molding mill where in cages 1-6 and roller wiring between them The sheet is formed into a semicylinder by an angle exceeding 180 °. In the wiring placed between cages b and 7, and in cage 7, the workpiece is unmolded, and from the ends of the billet, the length L equal to 0.3-0.7 unbending a profile to an angle of 1501 20 °, and decompressing the central part of the semi-cylinders to an angle of 170-150 °. The change in the angle of unbending at the end sections is determined by the dependence

 . p c-KX

where VP is the angle in the current section Xf

V. rassformavka angle of the central section;

For the deflow ratio, which is determined by the pipe size and mechanical properties 1 and metal:

  -. fes

Guo iJ -, TU, where 5 - the size difference in diameter At the central and end sections; Cc - radius of the central profile

plot

For pipes of low carbon steel grades 6g 30-45 kg / mm 0 1420 mm with a wall thickness of 14-17.5 mm, a reduction in the opening angle will lead to an increase in the horizontal dimension at the ends of a semi-cylinder larger than the nominal one, equal to JDu, the effect of the end effect when forming products of finite length.

In the manufacture of pipe F 1220 mm with a wall thickness of 14 mm from St 17G2AF, the sheet in the wiring placed in front of the stand cage of stand b is molded at an angle of 190, and in the wiring placed behind the stand of stand cage 7, the workpiece is unformed. In this case, forming the front end of zapigi from angle 120, gradually over a length of 550-650 voA from the end of the workpiece, is increased by an angle of up to 150 and keeps this angle constant during installation) - moving the central part and then reducing the angle to 120 °, which is also on the length of 550,650 mm from the rear end.

In the manufacture of pipe f 1420a with a wall thickness of 16.5 mm, the front end of the molded half-cylinder starts forming angle 130, gradually increasing to an angle of 160 ° from the end of the billet up to 160 ° from the end of the workpiece to a length of 550-650 mm from the rear end.

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FIG. R

In the manufacture of -pipes 0 1420 mm with a wall thickness of 14 mm from St, the sheet is molded at an angle of 190 °, and then decanted. At the same time, the shaping of the front end starts from an angle of 150 °, gradually increasing to an angle of 550-650 mm from the end of the workpiece to 170 and keeping this angle constant during the shaping of the central part with the subsequent reduction of the angle to 150 °, which produces also on the length of 550-650 mm from the rear end.

Changing the opening angle is done by diluting or

5 details of the deflecting rollers 8 and 9, which are controlled from the software device.

0

The prepact method for the manufacture of welded straight seam pipes allows, by stabilizing the profile of the half-cylinder during molding, to improve the quality of the pipes, i.e. reduce pipe transfer

5 in lowered varieties.

5-5

FIG.

Claims (4)

THE METHOD OF FORMING HAVE RECEIVED NDORIC TUBE Billets, at which the preform is molded to an angle exceeding 180 °, followed by molding to an angle of 170-150 °, characterized in that, in order to improve the quality of the pipes by stabilizing the geometric dimensions, the molding of the end sections along the length from the ends equal to 0.3-0.7 of the diameter _{of the} pipe, carry out to an angle of 150-120 This embodiment of the method allows to stabilize the geometric dimensions and thereby improve the quality of the pipes. This is achieved by the fact that as a result of different sizes of forming on the end sections 0.3-0.7 in diameter of the pipe from the end and on the central sections of the formed blanks (where the fixing conditions are different), horizontal dimensions (between the edges) at the ends and in the middle part are the same, which during subsequent redistribution will affect the quality of the end sections of the pipes. In FIG. 1 shows schematically a mill for implementing the proposed method, a general view; in FIG. 2, section AA in FIG. 1; in FIG. 3 section BB in FIG. 1; in FIG. 4, the layout of the forming rollers during the decoupling of the central part and end sections. The method of forming semi-cylindrical tube blanks includes sorting by mechanical properties and chemical composition, straightening sheets, gouging longitudinal edges and chamfering, the task of sheets in a roller-roll forming mill, where in stands 1-6 and roller wiring between them, the sheet is formed into a half cylinder angle exceeding 180 °. In the wiring placed between the stands 6 and 7 and the willow 7, the workpiece is molded, and on a length L equal to 0.3-0.7 of the pipe diameter, the profile is unbent from the ends of the workpiece to an angle of 150-120 °, and the central part of the half-cylinders is expanded to angle of 170-150 °. The change in the angle of extension at the end sections is determined by the dependence V < ^X * angle in the current section X; • angle of forming the central section; 'the coefficient of expansion, which is determined by the size of the pipes and mechanical properties! metal: k - b3 - the difference in size in diameter at the Central and end sections; - radius profile of the central section. pipes made of low-carbon steel grades 30-45 κγ / mmJ 0 1420 mm with a wall thickness of 14-17.5 mm, a decrease in the forming angle of Cr <120 ° will lead to an increase in the horizontal size at the ends of the half-cylinder more than the nominal one, equal to Ts _c . When Ch * p> 150 ° at the ends of the half-cylinders 65 affects the action of the end eff