SU1703224A1 - Method of preparing ends of tubular members for jointing - Google Patents

Description

Invention; relates to the field of assembly, namely, to the methods of preparation under the connected ends of the tubular elements with their subsequent connection between themselves with matting, soldering, balancing, and tacking 5 by other known methods, and Xin can be used for the manufacture of various pipelines, with an internal enamel coating .

The purpose of the scaling is to increase the useful characteristics of the joint by ensuring a high-quality coating of the surface of the chamfers.

The drawing shows the scheme of implementation of the method.15

The ends of the joined tubular segments 1 and 2 can be thickened 3 and A with any known method, for example, by draft or welding of the outer rings, with an increase in the outer diameter of the tubular elements and the preservation of the inner diameter. At the same time, a locking joint is formed at the ends of the tubular elements, for which an annular recess is made on the element 1, and a protrusion 5 in response to the element 2.

The step formed during the formation of the notch about the element 1. is made in the form of a chamfer, beveled towards the outer surface of this element, at the end of the protrusion 5 - a return chamfer. After that, the inner surface of the tubular elements 1 and 2 is prepared for coating. B. In the process of 35 shot-blasting or chemical cleaning, the end surface of the end of element 1 is cleaned simultaneously with the inner surface of the pipes. To do this, during shot blasting, the flight of the shot through the transition-40 sleeve should be directed to the tubular elements through the ends prepared for the connection. Coating is applied to the prepared surface. At the same time, the enamel slip 45 or weld glass glass easily flows onto the end surfaces of elements 1 and 2 located under the fragile surface when they are placed vertically, which eliminates the need for additional manual operations. 50

The tubular elements 1 and 2 are assembled together, they are pulled out with the help of an outer center, and the junction zone is heated to the softening temperature of the coating. When this happens, 55 fusion of the coatings on the grooves and the projection 5 of the castle with the formation of a monolithic coating of the internal surface of the pipeline occurs. Subsequent welding of the circumferential seam of the lock separated from the cover by a protrusion

does not lead to the formation of coating defects.

The connection of the tubular elements 1 and 2 can be made using the thread folder, flanges, or by any other known method.

In the case of the bottom preparation method, the case of preserving the coating of the end-pieces of the elements during transport is also ensured, since the protruding end of the element 1 and the outer edge of the chamfer on the lock 5 of the element 2 protect the coating 6 at the ends from accidental impacts.

The best angles and chamfers are angles of 30-60 ° to the axis of the tubular elements. At angles greater than 60 °, it is difficult for the coating to leak onto the ends. At angles less than 30 ° there is a danger of chipping the coating on the sharp edge of the chamfer. The optimum angle for making these surfaces is 45 °. In addition, chamfering increases the fusion area of the coating of the ends, which increases the reliability of the joint, as well as increases the mechanical strength of the joint under bending.

Example. Pipes with an outer diameter of 73 mm and a wall thickness of 5 mm were fixed in a pneumatic clamping press PG-100 and the ends of the pipes were planted out to a thickness of 10 mm and the length of the planted ends 15 mm with a special die and matrix. At the same time, at one end of the pipe with an inner side, an annular recess with a diameter of 73 mm was obtained with a chamfer that was beveled at a 45 ° angle. At the end of the second pipe, a protrusion with a diameter of 72.5 mm was formed, which was a form reciprocal with a chamfer at the end also at an angle of 45 °. At the same time, chimney pipes were prepared in the same way at angles of 20, 30. 60 and 65 °. The inner surface of the pipe was cleaned by shot blasting. At the same time, in order to reliably clean the surface of the recess and chamfers, the blasting was performed alternately in two directions at both ends of the pipe. For this, the pipe was turned 180 ° during the cleaning process. The cleaning of these surfaces occurred simultaneously with the cleaning of the inner surface of the pipes.

On the cleaned surface they applied a non-primer enamel coating of mark 155 in two layers. The slip was applied vertically by filling the pipe with the subsequent stock surplus. Pipe while oriented prepared end fjiiiic. As excess pipe flowed out of the pipe, the slip flowed onto the chamfer surface and was fixed in subsequent drying and firing operations. The drying of the slip was carried out at

: emg./lgurЈ 120 ° C, roasting at a temperature of - - () /.

re cl-u and

The quality of the coating was determined by visual inspection. Results about the table.

When docking, the torture point at the end of one pipe was brought into an annular recess at the end of the other pipe before the enamelled surfaces of the chamfers touched. After that, the interface with the help of a ring inductor was heated to a temperature of 750 ° C. in which the enamel is in a softened state. At the same time, due to the simultaneous squeezing of the joined pipes, the enamel coating on the ends was fused together. After removal of the heating device, a tack and welding of the joint were performed.

The use of this method provides high-quality coating on the ends of pipes and protects it from damage during transportation.

Claims (1)

Claims of Invention A method of preparing for the connection of the ends of tubular elements, mainly enamelled on the inner surface, in which an annular recess extending to the free end of this element is formed on the inner surface of one of the elements. the dimensions and the shape of the recess are made corresponding to the size and shape of the outer surface of the end of the second element, the transition between the inner surfaces of the recess and the tubular element is performed in a chamfer shaped obliquely towards the outer surface of this tubular element, at the end of the second tubular element a chamfer is also performed, which responds to this, which is different, in order to improve the performance characteristics of the joint by providing high-quality coating on the chamfer surfaces, the latter are angled 30-60 ° to the axis of the tubular elements.