METHOD FOR PREPARING TUBE EDGES FOR WELDING Russian patent published in 2006 - IPC B23K33/00 

FIELD: processes for welding thick-wall tubes without using additives, namely method for preparing tube edges for electron-beam welding.

SUBSTANCE: end of one of welded tubes is faced by means of cutter by angle 90° relative to its axis. End of other tube is worked by angle 90° relative to its axis inside tube and in upper portion of worked end annular protrusion is remained. Thickness and length values of said protrusion are no more than 4 mm. Technological groove is formed by means of cutter under said annular protrusion; depth and width of said groove are no more than 1 mm. With use of rolling out roller annular protrusion is bent outside by angle 45 - 90° relative to tube axis. Bent protrusion is turned for imparting to its cross section shape of isosceles triangle or isosceles trapezium or rectangle for forming protruded additive. In end of tube under protruded additive cylindrical cavity is turned with inner diameter equal to outer diameter of end of first tube. Said cavity is turned by depth equal to half of base of cross section of protruded additive.

EFFECT: simplified, reduced-cost process for assembling tubes for welding due to automatic centering of tubes at assembling.

3 cl, 6 dwg, 1 ex