SU1489870A1 - Method of producing welded pipes - Google Patents

Abstract

The invention relates to the processing of metals by pressure and can be used on continuous electric pipe welders. The purpose of the invention is to improve the quality of welded pipes and reduce the consumption of metal for their manufacture by reducing the crescent and eliminating the "biting" of the strip in the tension-bending device during the manufacture of welded pipes. The individual strips of the strip are welded into a continuous strip 3. Before forming, the strip is tensioned with a simultaneous alternating bend in the bending-tensioning device 2. Then the strip 3 is molded into a pipe billet and its edges are welded. Before alternating bending with tension, the strip 3 is twisted around its short edge at a given angle. This ensures a constant fit of both edges of the strip 3 to the surface of the input roller 4 of the bending and tensioning device 2. 2 Il.

Description

fib.1

- 1489870

The invention relates to the processing of metals by pressure and can be used on continuous pipe electric welding equipment.

As starting material for the manufacture of pipes on continuous pipe-welding units are used. rolled up strips (strips), from which butt-welded

strip, set in a pipe forming mill.

. During the manufacture of the strip on rolling mills, there is often a flaw in the place — the beginning of the Oxyz coordinate system at the point of contact of the short edge of the strip with the surface of the first along the roller 4 of the bending-tensioning device 2 as shown in FIG. 2. At the same time, the axis Og. directed to dopolty, due to the specifics of the process 15 of the supporting pair of rollers 1 and matches

which is a short edge, the height of the cylinder is the length of the short edge 1, and the radius of the base of the cylinder will be the width of the band b (Fig. 2).

The formula by which the camber angle is determined.

We place the origin of the coordinate system Oxyz at the point of contact of the short edge of the strip with the surface of the first along the roller 4 of the bending-tensioning device 2 as shown in FIG. 2. At the same time, the axis Og. directed to an extra pair of rollers 1 and matches

rocks: unevenness in thickness (transverse and longitudinal thickness variation), edge waviness, lengthening of the central part, rib crescent crescent) and others. In addition, the residual stresses in the metal during the cold rolling process are the cause of crescent at longitudinal cutting of wide strips into narrower ones used in the manufacture of pipes. Defects in the original billet have a negative effect on the stability of the processes of forming and welding pipes, leading to the appearance of scrap, an increase in metal consumption, deterioration and heterogeneity of the mechanical properties of the pipe.

The purpose of the invention is to improve the quality of welded pipes and reduce the consumption of metal for their manufacture by correcting crescent and elongation of the strip.

FIG. Figure 1 shows the section of the pipe-welding unit where the crescent-shaped strip twists in front of its alternating plate-bending with tension in the bending-tension device; in fig. 2 - cut-off strip, twisted before the first bending roller with an additional pair of rollers.

An additional pair of rollers 1 before the alternating bend in the bend-tensioning device 2 lane 3 is twisted in such a way that the short edge retains its initial position, and the length deviates from it (Fig.). When performing such an operation, the short edge will be the axis around which the twisting is performed (rotation) of the long edge. With this rotation, the long edge will have the appearance of a helix lying on the surface of the cylinder

with a taut short edge of the strip 3. And the axis Ox is parallel to the axis of the first bending roller.

The parametric helix equation, where the current twisting angle (rotation of the cross section) of the strip is taken as a parameter, has the form

X b-GOst, b-sint,

Z ii, t.

The length of the arc of the helix or the length of the long edge of the strip is expressed by the integral

b- / te) Mg)

P

(-)

five

whence after substitution of derivatives

B.cost

- "- b. sint il - s + n-sin-c ,. -:

at

E2 1

.w: „

at v

and integration we get the expression:

I l L

 f b

(i) N

After transformations of this curve with respect to the twist angle, we obtain

f

i R

one.,

Where

L is the length of the long edge of the strip; 1 - the length of the short edge of the strip; B is the width of the strip.

If lime is the size of the crescent-shaped strip in the form of a deflection a on the base length A in the horizontal plane, then the radius of the rib curvature of the strip in this plane is determined by the formula.

R

2a

and the length ratio is long and short

the edges of the strip with its width b will be equal to

s B,

1 RR

Taking into account the last two expressions, we obtain the formula for the ratio of the lengths of the edges of the strip

L 1 l. ъ 2a

one . TA72T + P

 When the sickle size fluctuates, the ratio L / 1 changes, and, accordingly, the angle. When the sickle of the opposite sign is changed, the long and short edges change places, changes the sign and the angle f. In the absence of crescent of the strip length of its edges

  X

are equal to each other 1), therefore

its twisting is not produced (O).

The method is carried out as follows.

Crescent strip 3, which is long and long, for example, the right edge after exiting the drive enters the device, for example, a pair of rollers 1, which moves along the length of the long edge. After this pair of rollers, the strip enters the bending and tensioning device 2 (Fig. 1), the distance between the pair of rollers twisting in the forest and the first roller of the bending and tensioning device 1, the short tensioning edge on this gap and its length also equal to 1, the long edge begins to rotate around the short one and tilts down (or up, depending on the nature of the coverage of the first bending roller), and the deviation angle from the position when the lengths of the edges are equal is Y (Fig. 2).

 The strip then enters the molding mill where it is molded into a tubular billet, the edges of which are welded in the welding unit. The diameter of the finished pipe is molded in the calibration tapes.

An example of the method implementation in the manufacture of pipes of size 102 to X 3.0 mm from schtrips 312 3.2 mm.

A strip with a crescent shape,. expressed in the form of a deflection and 20 mm on the base length A 3000 mm in the horizontal plane in front of the sign

bending with tension in a bending-tensioning device, is subjected to twisting by a roller pair, which is spaced from the first one along the roller of the folding-retaining device at a distance of 1,135 mm. In this case, the short edge in the specified tension interval and its length is also 135 mm.

The ratio of the length of the short edge to the length of the short edge is

i 3 ChU41o ° 5 The corner on which the strip will need to be twisted, so that the strip fits tightly to the input roller of the bending-pulling device is equal to

4-32

1,0055 - 1

 0.0456 glad or 2.6.

Thus, twisting a roller pair located 135 mm from the first bending roller, a 312 mm wide strip with the above crescent shape at an angle of 2.6, eliminates the break of the long edge on the first bending roller and sticking it in the subsequent bending rollers. tensioning device at their dense arrangement.

Claims (1)

Invention Formula A method of manufacturing welded pipes 35 that involves welding individual strips of strip into a continuous strip, stretching it before molding with simultaneous alternating plastic bending, shaping the strip into a tube billet and welding its edges, in order to improve the quality of the welded pipes and reduce the flow metal for their manufacture by correcting the crescent and elongation of the strip, before alternating plastic bending with tension, the strip is twisted around its short edge at the corner), determined from or 40 45 50  WITH .iL  B L is the length of the long edge of the strip; 1 - the length of the short edge of the strip; B is the width of the strip. Editor In, Kovtun Compiled by E. Vetrova Tehred A. Kravchuk Order 3614/15 Circulation 693 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 1.13035, Moscow, Zh-35, 4/5 Raushsk nab. Production and Publishing Combine Patent, Uzhgorod, st. Gagarin, 101 FU8. 2 Proofreader T.Malets Subscription