MANUFACTURE OF HIGH FREQUENCY BENT TUBE HAVING LOW HARDNESS AS WORKED

• Main Authors: INOUE SEISUKE, MATSUBARA YOICHI, TAKAGISHI MASAAKI, AKISAWA SEIICHI, NAOI HISASHI
• Format: Patent
• Language: English
• Published: 22.07.1988
• Subjects: 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 manufacture an inexpensive elbowless which has a small bend radius by high frequency bending,and also, whose hardness is <=HV 248 is worked, by heating the outside surface of a tube stock consisting of carbon steel of a specific component, to a range of 850-950 deg.C, and bringing it to bending, while executing water-cooling. CONSTITUTION:The titled method is used for manufacturing a high frequency bent tube whose radius of curvature is <=three times of the outside diameter of the tube, and carbon steel components as a tube stock are 0.05-0.25% C, 0.10-0.35% Si, and 0.30-1.00% Mn by wt.%, and as for the remainder, Fe and impurities are contained, and the component is limited to that which satisfies C+Mn/6<=0.33%. The tip part of such a steel tube 1 is clamped tightly by a clamp 5, heated until the outside surface becomes 850-950 deg.C, by a heating device 3 consisting of a high frequency inductor, and also, propelled in the direction as indicated with an arrow by a suitable means, by which the steel tube 1 is brought to bending. In such a way, an elbowless having a small bend radius, and also, having low hardness as worked can be manufactured at a low cost.