Incremental temperature difference bulging device for metal pipes and bulging method

Abstract

Disclosed are an incremental temperature difference bulging device for metal pipes and a bulging method. The incremental temperature difference bulging device comprises a bulging die, an electromagnetic induction heating mechanism and a coil feeding mechanism. A hole punch and a holeless punch are respectively located at two ends of the bulging die, and center lines of the hole punch, the holeless punch and the bulging die coincide. The coil feeding mechanism is located on the outer side of the bulging die, and an electromagnetic induction coil in the coil feeding mechanism is enabled to sleeve the outer periphery of the bulging die and to be coaxial with the bulging die. A clearance is reserved between the electromagnetic induction coil and the bulging die. In the process of heating and bulging, part of pipe blanks rather than the die are heated sectionally, the heated pipes are bulged, incremental temperature difference bulging of pipe parts is realized, forming property of materials is improved, resilience of the pipes is reduced, the problems of unstability and corrugation of the pipes are solved, and the pipe parts uniform in wall thickness distribution are obtained.

Description

Technical field [0001] The invention relates to the technical field of thermal bulging of metal pipes, in particular to an electromagnetic induction heating incremental temperature difference bulging device and method for metal pipes Background technique [0002] Metal pipes of various sizes and shapes are widely used in aerospace, automotive, petrochemical, and power systems. In aerospace and other fields, in addition to commonly used metal materials such as steel, copper, aluminum, and other metal materials, a large number of metal materials such as titanium alloys, aluminum alloys, and high-temperature alloys are also used for pipe materials. These metal materials have poor plasticity at room temperature and require forming. The pressure is large, and the rebound of the material is large, and the accuracy is not easy to control. Properly increasing the forming temperature can overcome these problems. Electromagnetic induction heating is the method of passing high-frequency al...

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Problems solved by technology

However, due to the limited heating temperature of the liquid medium, the heating and forming temperature of the pipe is limited, and the mold is heated during the forming process, which reduces the overall strength of the mold

At the same time, this integral heating and heat preservation method consumes a lot of energy, and it is difficult to ensure the uniformity of the pipe thickness during forming

[0005] Therefore, it is necessary to design an electromagnetic induction heating incremental temperature difference bulging device for metal pipes, which can only heat the tube blank without heating the mold, and only heat and bulge part of the pipe, and gradually form it using an incremental method Out of the pipe parts, solve the problem of instability and wrinkling of the pipe when the axial feed is combined with the gas pressure. At the same time, this incremental temperature difference bulging method can ensure the uniformity of the pipe wall thickness distribution after forming

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