METHOD OF RADIAL FRICTION WELDING OF POLYOLEFIN-BASE TUBULAR PARTS Russian patent published in 1997 - IPC

FIELD: production of thermoplastic pipes for handling aggressive media under pressure; radial friction welding of reinforced pipe and end face bushing. SUBSTANCE: in proposed method of radial friction welding of tubular parts made of polyolefin - base thermoplastics, initial interference mating is provided additionally over second seating surface. Mating over seating surface of smaller diameter is done on diameter not exceeding inner diameter of pipe reinforcement framework and on length commensurable with thickness of tube wall. Moreover, value of initial interference fitting over seat surface of smaller diameter is selected equal to 0.6-1.0 of initial interference value over seat surface of larger diameter. Support mandrel is fitted in central hole of pipe prior to mating the parts to be welded. According to other design version, value of initial interference over seat surface of smaller diameter is selected not to exceed 0.6 of value of initial interference over seat surface of larger diameter and radial expanding force is applied to inner surface of smaller diameter prior to relative rotation of parts to be welded. Expanding force should be uniformly distributed over circumference. Value of initial interference over seat surface of larger diameter is chosen to be equal to 1- 2% of value of this diameter. EFFECT: enlarged operating capabilities. 4 cl, 2 dwg, 4 tbl