Pulse-current pulse heating and gas-pressure forming device and method for difficult-to-deform alloy pipe fitting

Abstract

The invention discloses a pulse-current pulse heating and gas-pressure forming device and method for a difficult-to-deform alloy pipe fitting. As shown in figure 1, an upper mould and a lower mould are separately arranged at upper and lower sides of a to-be-formed pipe fitting, and formed parts are placed in cavities of the moulds; two semi-circular electrodes are separately embedded into the upper mould and the lower mould, and separately correspond to the two ends of a pipe; when the upper mould fits to the lower mould, the corresponding semi-circular electrodes define a circular ring shapeso as to be in sufficient contact with the pipe; the electrodes are externally connected with a high-frequency pulse power supply; and argon gas supercharging systems are connected to the two ends ofa sealed pipe. Low-pressure argon gas is firstly filled into the pipe, so that pressure in the pipe reaches a set value; then, the power supply is accessed, and the high-frequency pulse power supply emits low-frequency pulse current to heat the pipe, so that pressure in the pipe, the pipe surface temperature and relative load are in periodic fluctuation along with low-frequency pulse current, which are separately as shown in figures 2, 3 and 4; and pipe ring-direction temperature distribution is more uniform, the pipe is repeatedly expanded in an expanding process through pulsation changes ofload, expanding uniformity of the pipe expanding area is improved, and the local wall thickness is prevented from being reduced, so that forming performance of the pipe fitting is greatly improved, and precise forming for the pipe fitting with a complex shape is favorably realized.

Description

Technical field [0001] The present invention relates to the technical field of metal pipe air pressure forming, in particular to a pulse current pulsation heating air pressure forming device and method for difficult-to-deform alloy pipe fittings. Background technique [0002] In order to reduce the weight of vehicles, more and more parts are designed as hollow structures. In the automobile industry, the hydraulic bulging process of pipes is widely used in the production of hollow parts. However, the hydroforming process has certain limitations and cannot be used for difficult-to-deform metal materials such as titanium alloys and high-strength steels that have poor ductility at room temperature. Because the ductility of titanium alloy can be significantly improved only at high temperatures, but the pressure medium for hydraulic bulging, whether it is water or oil, restricts the working temperature of hydraulic bulging from being too high. Therefore, the hot air bulging process of...

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Problems solved by technology

However, this method uses a flame to heat the aluminum alloy tube, the heating time is long, the efficiency is low, and the size of the flame is not easy to control accurately, and the control of the pulsating pressure requires a set of independent equipment, which costs more

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