PRODUCTION OF WELDED PIPE

摘要

PURPOSE:To form the skin materials of the inside and outside surfaces of a welded pipe of a metallic plate material having the skin materials on the inside and outside surfaces to the same thickness in the stage of producing said welded pipe by forming the skin materials of the blank material thicker in thickness on the side that comes on the outer side after forming and thinner on the side that comes on the inner side. CONSTITUTION:A strip plate material 10 for pipe making produced by coating skin materials 12, 13 as brazing filler metals on both surfaces of a steel plate 10a as a core material is formed to a pipe shape by roll forming and the end parts thereof are welded, whereby a multi-layered pipe is produced. Here, the material 13 for forming the skin part on the outer side of the multi-layered pipe is formed to the thickness 1.05- 1.52 folds the thickness of the skin material of the completed multi-layered pipe and the material 12 for forming the skin part on the inner side of the multi-layered pipe is formed to the thickness 0.75-0.96 folds the thickness of the skin material on the inner side of the completed multi-layered pipe. Since the material 13 receives pulling and the material 12 compressing during formation to a pipe shape by roll forming, the multi- layered pipe having the skin materials of the same thickness of the inside and outside skin material is obtained.