METHOD OF PRODUCING CURVILINEAR TUBES FROM FORMED HALD-BRANCH PIPES Russian patent published in 2011 - IPC B23K31/02 B23K9/23 B23K37/04 

FIELD: metallurgy.

SUBSTANCE: proposed method comprises assembling half-branch pipes, fixation of edges and fusion welding of lengthwise butts. Edges are fixed by point-contact welding at two points on feeding filler wire under electrodes at (45 -90)° to butt line. Filler wire is pressed against the floor by branch pipes. Wire contracted, it is axially loaded by expanding force equal to (0.1…0.2)σ_B, where σ_B is wire material ultimate strength, MPa, not exceeding force of wire teat off from half-branch pipe. Then, current pulse is sent through electrodes to melt wire through and melt half-branch pipes at points of contact with wire. Note that fixture pitch is set equal to (1.0…2.0)D_o, where D_o is branch pipes diametre, mm.

EFFECT: higher efficiency.

6 dwg, 2 tbl