Electromagnetic moldless forming method and device of pipes based on background magnetic field

Abstract

The invention discloses an electromagnetic moldless forming method and device of pipes based on a background magnetic field. The device comprises a Helmholtz coil system, a support rod, upper and lower support plates, a driving rod, a pulse discharge circuit and a forming coil. The background magnetic field is combined with a pulse magnetic field to realize uniform electromagnetic bulging of the pipes (such as aluminum alloy pipes). The nonuniform flowing of corresponding plastic deformation areas of the pipes deformed at high speed is stopped by a nonuniform resistance field formed by electromagnetic damping in the background magnetic field, so that the pipes generate no local thinning or spalling, and qualified expansion pipe fittings with uniform plastic flowing are obtained. The Helmholtz coil system can accurately control the input energy of the background magnetic field, so that the final forming shapes of the pipes are precisely controlled, such defects as high size fluctuation and weak process repeatability of expansion pieces in a traditional electromagnetic free expansion process are prevented, and the batching, the mechanization and the standardization of the process are realized.

Description

technical field [0001] The invention belongs to the field of plastic forming of materials, and in particular relates to an electromagnetic moldless forming method and device for pipes based on a background magnetic field. Background technique [0002] Electromagnetic forming is a forming method that uses Lorentz force to cause high-speed plastic deformation of metal materials. During forming, the electric energy is converted into high-voltage shock waves in a very short time, which acts on the billet in the form of pulses, so that the billet obtains a very high deformation speed instantly, and then undergoes plastic deformation under the action of inertial force. This technology is mainly used in the fields of aerospace, weapons, electronics and automobile manufacturing, especially in the free bulging process of pipes. [0003] When the pipe undergoes electromagnetic free bulging, after the switch is closed, the induced current has a "skin effect". At the same time, there i...

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Problems solved by technology

[0005] In order to overcome the deficiencies in the existing electromagnetic free bulging technology of pipes such as uneven plastic flow, severe local thinning and even cracks, the present invention provides an electromagnetic dieless forming method and device for pipes based on the background magnetic field

To solve the technical problems existing in the existing technology such as difficult operation, poor process repeatability, uncontrollable dimensional fluctuations, and unsuitable for mass production requirements

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