SU1681995A1 - Method of producing bent metallic tubes - Google Patents

Abstract

The invention relates to the processing of metals by pressure, in particular, to methods for bending multi-layer thin-walled pipes. The purpose of the invention is the expansion of the range of parts produced. The multi-layered pipe-blank is shaped, and at the same time a cutting line is drawn on its outer surface, after which the alternate layers of the part are removed. 1 hp ff, 3 ill.

Description

The invention relates to the processing of metals by pressure, mainly to the flexibleness of direct very thin-walled pipes on pipe-bending equipment, and can be used in shipbuilding, aircraft construction, civil and industrial construction, where special thin-walled spatial air ducts are widely used for the ventilation system and air conditioning. air, as well as in other industries where curved extremely thin-walled pipes are required.

The aim of the invention is to expand the range of parts produced.

Figure 1 shows a multilayer pipe billet; figure 2 - the same, at the stage of cutting rollers; fig.Z - the same at the final stage of processing.

The method is carried out as follows.

The intermediate multi-layered billet pipe (MTZ) shown in FIG. 1 consists of three straight sections with lengths h, 12, (three-curved sections, conventionally designated 11, II, III with bending centers Oi, 02, Oz, bending angles). , az and average bending radii P sr1izg, Isr2izg, VsrZizg respectively.

Its inner diameter is OVn, outer diameter is He, and DCp is equal to the diameter of the pipe, i.e. DCp DTp. The wall thickness of the MTZ is equal to the product of the thickness of one layer and the number of layers. From the end face of MTZ, the internal and external longitudinal edges of MTZ are clearly visible. The first one died MTZ was made in the XY cavity, the second one died - in the YZ plane, and the third one died, projected on the XY plane - in a plane located at an angle ft to the YZ plane.

Figure 2 shows a part of MTZ 1 in the initial period of cutting with cutting rollers fixed in holders 2 and 3. The cutting depth is equal to the thickness of one layer S, which is due to the design of the cutting roller, the depth of penetration of the cutting edge of which is limited to this value.

Fig. 3 shows the process of making the finished spatial tube from two halves 4 and 5, which are located with a maximum gap at the end of the size n and angle of converging edges y. The edges are joined by a die 6 moving from one end of the already joined part to another part consisting of two halves. In the die, there are electrodes 7, which are welded

Yo

ON 00

H Yu SL

Coupled halves of one layer are put into the finished pipe. The manufacture of the latter ends with the passage of a die with electrodes installed in it to the second end.

Example. Spatial pipes of ventilation systems with a nominal diameter Dy of 100 mm and an outer diameter of DTp 106 mm, a wall thickness of 5-1 mm, an average bending radius of Rsrizg ± 1.5 From, a bend angle equal to 90 ° C are manufactured. 20 such tubes are required.

The method begins with determining the length of the overcurrent protection. Its length is equal to

. . , , t 3 2 ts Vigr + l2 + l3 + §

The straight sections I, 12.1z are equal to 200.150.100 mm, respectively. Then the length of the MTZ is equal to

L 200+ 150 + 100 +

+ 3-2-3.14-1.5-106 1200mm

Taking into account this length, MTZ choose flat blanks of equal or greater width, on which marking lines are applied with a distance from each other without taking into account the cut width by the value of l DTp 3.14-106 333 mm. The slab is then rolled into a roll with marked lines on the outer surface. Having obtained the first inner layer with an inner diameter of DBH of 96 mm, welding its edge to the subsequent layer by welding, then the remaining nine layers are wound up to an outer diameter of DH 116 mm and similarly grab the outer edge.

Made MTZ bend to the intermediate configuration shown in figure 1. In this case, it is most expedient to carry out its bending with steep bend radii Xsrizg 1.5 Dip using induction heating of the bending zone by high-frequency currents.

A straight-through length overcurrent overcurrent protection device is installed on the machine, fixed in its equipment so that the beginning of heating falls on the beginning of the conditional section I, and bend it through an angle of 90 °. After that, the finished conditional section I is removed from the equipment and the MTZ is fixed again so that the beginning of the repeated

heating accounted for the beginning of conditional section II, while the conditional section I is placed in a vertical plane with a bend upwards. By bending this section

by 90 °, in a similar manner, it is removed, moved to a new position and secured by overcurrent protection. When this conditional curved section II is first set in a vertical plane, bend upward, and

then they rotate around the axis by an angle / in the direction of the bending of conditional section III. Performing similarly the third bend at 90 ° receive an intermediate overcurrent, shown in figure 1. Then as indicated

2, a longitudinal section is taken of each outer layer, removed from the overcurrent protection device, the edges are closed and placed in the nozzles opposite the holes of the latter. Having installed the electrodes in the hole, weld

these edges, moving the nozzles with electrodes from one end to another, as indicated in FIG. These operations are repeated 10 times, thus obtaining 10 spatial tubes of 106 x 1 mm.

Claims (2)

1. A method of manufacturing bent metal pipes, preferably thin-walled, consisting in rolling a flat billet into a multilayer pipe stock, its bending and subsequent longitudinal cutting, characterized in that, in order to expand the range of the parts obtained, when cutting a multilayer pipe billet, cut lines are cut on its outer surface along the formative, spaced one from the other without taking into account the width of the cut, for the length of the semi-circle of the finished pipe, fix the outer and inner longitudinal edges of the multilayer the pipe billet, bends it, after which it is cut from both sides of the semifinished product along previously marked opposite cutting lines, and then each layer, the production of the formation of these finished parts. 2. A method according to claim 1, characterized in that, after removal of the next layers from it, the next layers are folded to a more complex configuration. z li acp psmag Fy FIG. 2 ZA four fig.Z 1 pcs a / you