PRODUCTION OF CURVED PIPE MATERIAL

• Main Authors: NAGAI TSUTOMU, OGAWARA YOSHIO
• Format: Patent
• Language: English
• Published: 14.09.1984
• Subjects: AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKINGWITHOUT ESSENTIALLY REMOVING MATERIAL; MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES,OTHERWISE THAN BY ROLLING; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; PERFORMING OPERATIONS; PUNCHING METAL; TRANSPORTING; WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS ORPROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL

PURPOSE:To obtain easily a curved pipe which is walled to an equal thickness and has high accuracy by forming a round bar-shaped blank material to a straight pipe-shaped semiprocessed product provided with the uneven wall thickness to be made eqaul in thickness by curving in the pipe part between the end parts of bulged and straight pipe parts and bending said product. CONSTITUTION:A desired pipe hole 1 is opened by forging, grinding etc. in a round bar-shaped blank material M over the entire length, and the 1st bulging part 2 for coupling is formed at one end thereof and an equally walled straight pipe-shaped part 3 at the other end. The uneven thickness to the extent that the part to be positioned on the inside in the stage of bending is thin and is increasingly thickly walled toward the outside and that these parts are made equal in thickness on account of the walldeformation occuring in the compressing force and stretching force in the axia line direction to be generated in the stage of bending the pipe part 4 between the parts 2, 3 is provided in said pipe part. The part 4 of the straight pipe-shaped semiprocessed product N formed in such a way is subjected to a bending treatment such as ironing or the like for the purpose of bending the same to an approximately 90 deg.C arc. The 2nd bulging part 3' for coupling as a result of build-up by driving, etc. is formed on the part 3 according to need and a finished product N' is obtd.