Keyword: «saddle branch»

The paper proposes a technology for welding a saddle branch to polyethylene pipes, which allows to extend the range of permissible ambient temperatures for welding to minus 45 ° C. Shown are the results of separation tests of welded joints obtained at low temperatures. The use of the developed welding technology ensures the formation of a material structure in a welded joint, similar to the structure of the material of a welded joint obtained under conditions of permissible temperatures.

The paper presents the results of studies of a material structure formed in the process of the developed technology for welding a saddle branch to a polyethylene pipe at low air temperatures. The temperature-time mode of welding saddles to a polyethylene pipe at low temperatures, implemented by the proposed technology, makes it possible to obtain a material structure that ensures the strength of the joint at the strength level of standard welding at permitted air temperatures.

Developed and proposed technology for welding a saddle branch to a polyethylene pipe makes it possible to work at low ambient temperatures without constructing temporary heated shelters. Experimental welding took place in the natural conditions of the city of Yakutsk. Quality control by pull-off tests of the obtained welded joints showed the effectiveness of the developed technology for welding a saddle branch to a polyethylene pipe.

Based on the analysis of the stress-strain state of welded joints, it is shown that when welding saddle branches to existing gas pipelines at low temperatures using the proposed technology and standard welding, the differences in the values of stresses and displacements occurring are insignificant. Numerical calculations have shown that when welding a saddle branch at low temperatures using the proposed technology, it can be expected that the joint strength will not be lower than when welding under standard conditions.