Superplastic forming and processing method for sheets and superplastic-forming air pressure loading device thereof

Abstract

The invention discloses a superplastic forming and processing method for sheets and a superplastic air pressure loading device, and belongs to the technical field of superplastic forming and processing of the sheets. The method and the air pressure loading device are characterized in that: the superplastic deformation of the sheets is always controlled within or close to the range of an optimal strain rate so as to give full play to the superplastic performance of the materials and improve the wall thickness uniformity and use performance of formed parts. The air pressure loading device comprises a control system, an upper mold air pressure loading system, a lower mold air pressure loading system and a vacuum system for the upper and lower molds. The superplastic forming and processing method and the air pressure loading device can perform processes of superplastic forming, back pressure forming and positive and negative forming on the sheets such as high-temperature alloys, titanium alloys, aluminum alloys, magnesium alloys, metal matrix composites, intermetallic compounds and the like to form complex part shapes.

Description

technical field [0001] The invention relates to a sheet material superplastic forming processing method and a superplastic forming air pressure loading device used in the method. Background technique [0002] Superplastic forming is a precision forming process for manufacturing difficult-to-machine material parts and complex structural parts. In superplastic forming, the deformation of the material in the cavity depends on the thinning of the sheet thickness. For parts with complex deep cavities, the stress state at each point of the sheet metal during the forming process is different and changes with time, resulting in poor wall thickness uniformity of the formed parts. Finally, the degree of deformation of the molding part is too large, and the internal void fraction is high, which reduces the performance of the formed part. Improving the uniformity of wall thickness of formed parts is one of the focuses of people's attention. The technical measures to improve the unifo...

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Problems solved by technology

In the early days, superplastic pneumatic loading devices relied on manual intermittent control of the opening of the valve, which inevitably caused the strain rate to deviate from the optimal range

C.H.Hamilton of the United States has successfully developed a pneumatic loading system controlled by a single-chip microcomputer. The forming air pressure can be continuously adjusted according to the pressure p-time t curve obtained by simple mechanical analysis, the control accuracy is greatly improved, and the operation is more convenient. However, the pneumatic loading system controlled by a single-chip microcomputer cannot Perform back pressure forming and front and back forming

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