SU707751A1 - Method of making laminated tube blanks - Google Patents

Description

I

The invention relates to the field of mechanical engineering, in particular, to methods for producing curvilinear multilayer tubular blanks intended for connection to pipe fittings and body products used in atomic, gas, petroleum and chemical engineering.

A method for manufacturing curvilinear multilayer blanks is known 1.

The disadvantage of this method is the low quality of the workpiece.

For the manufacture of hollow elements, it is necessary to use billets machined with high accuracy by matching diameters or calibrated using plastic deformation methods.

The most significant drawback of the method is the impossibility of obtaining 1 × 1 large-sized circular bend taps, for example, with a radius equal to the diameter of the tube blank and an angle of 180, as well as torus-type blanks.

This is due to the fact that the pushing force of the tubular element increases rapidly.

Depending on the bend radius, wall thickness, diameter of the workpiece, which leads to the appearance of a gap between the layers.

When the layer is cooled, it is possible that there are large residual tensile stresses that can cause a crack across the surface.

The aim of the invention is to eliminate these drawbacks and higher strength parameters of manufactured blanks, for example, attached to pipeline fittings or body products, and to expand the technological capabilities of the process.

In order to achieve this goal, the layering of the drying is done by preformed dispensing with the required bending radius by sector pieces, the edges of which are pre-cut, and after layering are interconnected, for example, by welding.

Claims (1)

FIG. 1 pre-formed preformed sector element; in fig. 2 shows an intermediate stage of assembly of a multilayer outlet; in fig. 3 - the finished product. 37 The method is carried out as follows: Pipe I, which is the inner layer, is pressed along the radius corresponding to the required value of the radius of the outlet to the accepted angle of outlet. Next, hollow elements 2 of the second layer are prepared. To do this, use seamless pipe or with longitudinal seams of the billet. The blanks are produced by forming by dispensing with the required bending radius in a cold state, which allows achieving high accuracy of the 1-DIF of the deformation of the blanks. In accordance with the calculation of the geometric parameters of the layer cut off the end annular edges. The required cutting edge can: be implemented using a rational cutting before forming. Lamination is carried out, for example, according to the thermal structure, i.e., by plating. The layered element is heated to the required temperature not exceeding the scaling temperature of the material, (and 1, for steel about 500-600 ° C), after which it is oriented relative to one of the ends of the inner tube and laminated to it. After filling the entire layer with the required number of sectors, the annular edges are joined, for example, by welding. All subsequent layers are layered in a similar way. The seams are shifted relative to each other in a certain sequence, eliminating the coaxial arrangement of welded joints. PRI m. E. Seamless tubular billet. with a diameter of 40 mm was bent on the radius of the outlet (mm). . For sectoral elements, seamless pipe billets with a wall thickness of 5 mm, preformed by dispensing and curved to the outlet radius, were used, while the diameter of the original blank of the second layer (following the main pipe) was 116 mm, and 119 mm, for the third layer, respectively, 127 and 129 mm, while the ends of the sector elements were cut off. After layering of the sector elements on the main pipe, there was an additional pipe with a bend radius of 330 mm, an outer diameter of 140 mm and a wall thickness of 15 mm. At the end of the assembly, a favorable distribution of stresses is created in the cross section, while the inner layers are under the action of compressive stresses, which increases their operational reliability. The implementation of the method does not require unique special equipment. The method has wide technological capabilities to produce pipeline elements of any structural form and geometric dimensions, for example, compensatory multilayer knees, multilayer toroidal elements. This method allows the use of universal forging and heating and heating equipment. 0: throw economic effect will be 7 tons. Rub. per ton of multi-layer construction compared with monoland. Formula cut, and after laminating the edges are interconnected, for example, by welding. Sources of information taken into account during the examination 1. M. Chepurko. Bimetallic pipes, M., Metallurgizdat, 1974, p. 47 IPuz.f FIG. g