SU706143A1 - Method of coupling tubes for continuous reducing - Google Patents

Description

one

The invention relates to the field of pipe production, and more specifically to methods for connecting pipes before they are continuously reduced in a reduction and expansion machine,

Continuous reduction of pipes is one of the most promising ways to reduce the end-cut rough when they are reduced from tension |, however, significant difficulties arise when connecting pipes to an endless whip.

There is a known method of joining pipes for continuous reduction, including pre-settling of pipe ends, welding, cutting of ends and screwing of couplings l.

The disadvantage of this method is the complexity of the process of connecting the ends of the pipes.

. A method of joining pipes, for continuous reduction, is also known, which involves connecting the pipe ends using stationary butt welding machines 2j.

) Such a method is the unreliability of the joint by welding due to

inaccuracies of the geometric dimensions of the pipes-in their place. connections and bulkiness of equipment.

The closest in technical essence to the present invention is a method of combining coarse for continuous reduction, including preliminary deformation of the ends of the pipes (compression of one and distribution of the other), introduction of the end of one rough inside the other and joint reduction of the ends of the pipes heated to temperature. reduction pipes to a diameter not exceeding the diameter of the pipe after reduction h.

Claims (3)

A disadvantage of the known method is the low strength of the joint of the pipe ends, which causes ruptures to rupture when reducing with tension, and also leads to the need to increase the length of the connection which is coarse and thereby increase the consumption of megaloles after reduction. The aim of the invention is to reduce the cutting of the tubes by reducing the length of the ends to be joined coarse. The target is achieved by strengthening the joint by lowering the temperature at the docking site by more than 10%. . The essence of the method lies in the fact that before rolling on the reduction and expansion mill, the front ends of the pipes are burned to a diameter smaller than the internal diameter of the pipe, and the front end of each rolled pipe is inserted inside the rear end of the previous pipe. Prior to inserting the end of one tube into the other or immediately thereafter, the tubes are heated, for example, in pass-through induction heaters, to a reduction temperature. The ends of the heated pipes, connected to the socket, are jointly compressed to a diameter equal to or less than the diameter of the finished pipe after the reduction mill, and the junction of the ends of the pipes is cooled to 100 ° C or more. Cooling of the joint of the pipe ends can be carried out by supplying this section of water from the sprayer after the pipe ends are crimped together, including by supplying water from the rolling sprayer moving together with the pipes along the rolling axis and returning to the original position after cooling. pre-cooling more than 20% of the crimped end of one and the pipes, which are inserted inside the heated end of the other pipe, and which, after the pipe ends are jointly crimped, the heat is taken from the outer pipe section, it cools their joints are more than 10% relative to the heating temperature of the pipes. ,, Cooling the joint of the pipe ends increases the strength characteristics of we thall, increases the strength of the joint itself. In addition, due to thermal contraction, when cooling the outer portion of the joint, additional thermal compressive stresses occur on the contact surfaces of the pipe ends, which increase the strength of the joint due to better adhesion. Due to the fact that the diameter of the pipe at the joint section does not exceed the diameter of the finished pipe, the cooled section of the connected ends, which has strength characteristics, is more than 1.5 times greater than the rest of the pipe, passes through a reduction mill without recess rolls, but up “lichipa legs-ruzki on equipment. Pa trubop1: ukptnaya mustache, g "povka with a continuous povryvochn1 1M mill, which includes a two-tetrachipethe reduction and extension mill, ci; ioco6 as follows. A rough pipe obtained by a non-continuous mandrel mill, after removing the mandrel from it, is directed to forging rollers, on which its front end with a length of 0.7-2.0 in diameter of the pipe compresses dp the size of the smaller diameter of the finished pipe. The pipe is then heated in induction heating furnaces to a reduction temperature of 800-1100 ° C, and the front end is introduced inside the rear end of the previous pipe. After this, the ends of the heated pipes on the forging rollers are jointly crimped to a diameter equal to or smaller than the diameter of the finished pipe after the reduction mill. The pipe joining section is cooled to 10 ° C with water from a rolling sprayer moving along the pipes along the rolling axis, after cooling the sprayer returns to its original position. As the pipe is rolled in the reduction mill, the joint section enters the mill and passes through it, preferably without being rolled by rollers. At the same time, the rear end of the pipe, still moving along the shaft, is connected in the same way to the front end of the subsequent pipe. The introduction of the proposed method of joining pipes on pipe-rolling installations with reduction and stretching mills, on which continuous rolling of pipes is carried out, reduces pipe cuts (joints) by a factor of 1.32, 0 by increasing the connection strength and reducing the length of the pipe ends to be joined . Claim method of joining pipes for continuous reduction, containing preliminary deformation of pipe ends, insertion of the end of one coarse part into another, their joint reduction at the temperature of reduction to a diameter not exceeding the diameter of the pipe after reduction, so that , that  7O61 / 136 Pour pruned rough by diminished-1. Patent of Germany No. 1002318 sheni dpina connected 1 ends, consolidation-kn. 7/37/06, 1971 southward connection by lowering the temperature, 2. USSR author's certificate in the place of docking by more than 10%, № 119503, кп. B 21 B 17/04, 1959. Sources of information, s 3. Patent of Germany N 1602182, taken into account during examination. 7 a 17/14, 1971.