METHOD OF ARC WELDING OF TRIPLE CONNECTIONS (WELDOLETS) OF THE MAIN PIPELINES Russian patent published in 2018 - IPC B23K9/235 B23K31/02 B23K101/10 

FIELD: electricity.

SUBSTANCE: technological hole in the pipe is made. Welding groove is performed, edges in the temperature range from 150 to 200°C are pre-heated and intermediate layer of welded metal is applied to the weldolet grooving surface with thickness from 4 to 7 mm. Then, the welded rollers are applied over the contour of the grooving with the formation of a welded belt with a width of at least 2.5 of the pipe wall thickness and cooling the welded joint by applying a heat-insulating belt. Wherein, when this intermediate layer is applied, metal is used, mechanical properties, of which according to the criterion of elongation are on 18-35% higher than mechanical properties according to the criterion of the elongation of the parent pipe metal and welded layers of weld metal. The superposition of welding rolls is carried out with the exposure of interlayer temperature between the superposed welding rollers in the temperature range from 50 to 250°C.

EFFECT: invention allows to improve the quality of welded joint.

5 cl, 1 tbl, 1 ex