METHOD OF PRODUCING BIMETAL TUBE Russian patent published in 2012 - IPC B23K1/08 B23K101/06 B32B15/01 

FIELD: process engineering.

SUBSTANCE: invention may be used for production of diverse bimetal tubes tightly bonded over their entire contact surface intended for operation in aggressive media with high content of abrasives, etc. Proposed method comprises assembling composite biller made up of two diverse coaxially-arranged tubes, inner one being shorter than outer tube by some 1-2 mm. Clearance on assembly end face is welded by vacuum-tight seam wherein tube ends are located in one plane. Then plug is welded by vacuum-tight seam on opposite end of said assembly. Said assembly is arranged vertically for said plug to make its bottom and to place solder on plug inner bottom. Branch pipe connected with vacuum booster pump and cylinder with non-oxidising gas is welded by vacuum-tight seam to assembly top part. Said assembly is evacuated. Said assembly is fitted into vertical tube furnace to be heated to solder fusion. Compressed gas is used to force liquid solder in evacuated clearance. Solder crystallisation in clearance is performed by slow lifting of said assembly from the furnace.

EFFECT: seam with no pits, reliable joint of tubes to allow their cold forging.

6 cl, 6 dwg