PURPOSE: To perform removing a distortion in both ends of piping joint without rearranging a metal mold, by forming the distortion removing metal mold of moving/fixed metal molds of dividing into two parts in a center part in a horizontal direction a plurality of circular back facings having an opening part facing upward in a transverse 1 line with a different diameter on the same line.
CONSTITUTION: A 2 inch side end part 12a of a different diametric piping joint 12 is inserted to a semicircular arc-shaped back facing 2a of a 2 inch use fixed metal mold 2, to hold an end face 12b of the different diametric piping joint 12 pressed by hand so as to be closely attached to a bottom surface 2g of the semicircular arc- shaped back facing 2a. A moving metal mold 1 is moved in a direction of a fixed metal mold 2, to press an external diameter of the end part 12a of the different diametric piping joint 12 by each semicircular arc part 1h, 2h of the moving/fixed metal molds 1, 2, to remove a distortion. After removing the distortion, the moving metal mold 1 is made to take refuge to a side of an actuator 5. The different diametric piping joint 12 is inverted, to insert an end part 2c in a 3 inch side to a semicircular arc-shaped back facing 2c of the 3 inch use fixed metal mold 2, and a press distortion is removed similarly to removing distortion in the 2 inch side.
SATO KENJI
AKIYAMA TAKAYUKI
