METHOD OF MANUFACTURING OF AXISYMMETRIC WELDED PRESSURE SHELLS Russian patent published in 2015 - IPC B23K31/02 B23K33/00 B23K9/16 B23K9/23 B23K101/12 

FIELD: machine building.

SUBSTANCE: shell pipe blanks are made out of structural alloyed steels for cold-forming. The shell blanks are subjected to the strain hardening by the rotating drawing by several transitions. At the last transition the shell blanks are subjected to the thermal strain hardening by quenching with tempering with the blank heat fixing on the expanding mandrel, grit blasting of the external and internal surfaces, rotating drawing and annealing. The lathe turning is performed with formation of the welded edges. The shell and rings is assembled on the expanding mandrel with removable shim with butt joint clearance 0.15÷0.2 of thickness of the welded edges with fit-up of the butt edges by means of diametrical tension within range of the elastic deformations by value (0.1÷0.15)% of actual length of the edge circle. Automatic welding is made with consumable electrode by single pass with through penetration of the welded edges. The low temperature tempering and X-ray testing of the welds are performed the welded rings are machined with production of the buttress thread, the shell is hydraulically and pneumatically tested.

EFFECT: method ensures high mechanical properties of the axisymmetric welded shells at low residual internal stresses, high accuracy of geometrical dimensions.

2 cl, 5 dwg, 1 ex