METHOD OF FRICTION WELDING OF TUBULAR PARTS Russian patent published in 2019 - IPC B23K20/12 B23K101/04 

FIELD: machine building.

SUBSTANCE: invention can be used for friction welding of connection of tubular parts of drilling lock - nipple and coupling with pipe. Lock part and pipe are installed in support with their ends. On one of welded parts at conjugated end ring-shaped projection with conic surface is pre-made, and on the other - mating conical surface. Parts are installed with formation of diametrical gap between their conical surfaces, which is eliminated upon application of heating pressure. Lock part is rotated with simultaneous application of heating pressure to it at fixed pipe, and after rotation is stopped, forging pressure is applied to fit said conical surfaces with interference. Axial force of tightening conical connection creating interference is determined by average contact pressure q_m conjugated conical surfaces, proceeding from combined action of differences of limit values of tensile loads and torsion of sections of welded joint and solid pipe body under condition that q_m≤0.5σ_t. Welding and tightening of conical connection are synchronized.

EFFECT: combined strength of welded and conical joints as per loads of tension, torsion and sign-changing bending is not worse than strength of pipe with solid body and upset ends.

3 cl, 4 dwg