JPS5611111A - Manufacture of elbow by bending pipe possessing irregular wall thickness - Google Patents

Abstract

PURPOSE: To contrive to reduce the working cost required at the place where the use of the elbow is inevitable, by applying the high frequency induction heating and bending, which are both freely adaptable to any bending radius, to the pipe possessing irregular wall thickness or to the round steel bar, in manufacturing the pipe with uniform wall thickness.

CONSTITUTION: The inner surface of the pipe possessing the wall thickness to be specified by T=(designed minimum wall thickness) ÷(1- thickness reducting rate) (the round steel bar is also available) is mechanically machined to form the irregular wall thickness, and thus obtained thin wall thickness is specified as (the designed minimum wall thickness) ÷ (1+ thickness increasing rate). This pipe 1-1 of irregular wall thickness is fixed by the guide support clamp 2 and the middle point clamping jig 3 so as to place the thick wall T on the outside and to place the thin wall C on the inside in respect of the bending neutral axis; and the tip of the pipe 1-1 is clamped by the arm point 6 being set at the specified radius R centering at the bending point 4. At the middle of the pipe 1-1, the guide roller 7 and the flattening preventive guide 8 are installed; then while the pipe 1-1 is being heated to the specified temperature by the work coil 11, the pipe 1-1 is pushed and bent by the hydraulic cylinder 10, the pipe feeder 9 and the jig 3; following to this, the bend zone Z is directly cooled. After, that the pipe 1-1 is cut at the planes X-X and Y-Y, and the elbow is obtained.

COPYRIGHT: (C)1981,JPO&Japio