Hydraulic expansion forming process

Abstract

The hydraulic bulging process with metal pipe as prefabricated part includes setting the metal pipe inside mold, sealing ends of the metal pipe, and filling high pressure liquid into the pipe to form inside the mold. Using metal pipe as prefabricated part needs only welding metal plate into pipe and no complicated drawing and annealing process, so that the present invention has high production efficiency, saving in material, simple apparatus and low cost.

Description

technical field [0001] The invention relates to a hydroforming process. Background technique [0002] Expansion molding is a processing method that uses pressure to expand a prefabricated part with a smaller diameter from the inside to the outside to form a larger diameter or cylindrical special-shaped part, mainly including steel mold expansion method, rubber mold expansion method, hydraulic expansion method, etc. . The mold structure of the steel mold expansion is complex, and the accuracy is difficult to guarantee; the rubber expansion mold is limited by the characteristics of the rubber, the expansion force is uneven, and defects are prone to occur; the hydraulic expansion mold has simple process, low cost, and uniform expansion, which is widely used. The current hydraulic expansion process generally processes cylindrical or conical prefabricated parts, but the forming process of preparing cylindrical or conical prefabricated parts is relatively complicated. Taking cyli...

AI Technical Summary

Problems solved by technology

However, the mold structure of the steel mold expansion is complex, and the accuracy is difficult to guarantee; the rubber expansion mold is limited by the characteristics of the rubber, the expansion force is uneven, and defects are prone to occur; the hydraulic expansion mold has a simple process, low cost, and uniform expansion, which is widely used.

The current hydraulic expansion process generally processes cylindrical or conical prefabricated parts, but the forming process of preparing cylindrical or conical prefabricated parts is relatively complicated. Taking cylindrical prefabricated parts as an example, the following steps are generally required: ①Cutting, cutting the sheet into a circle; ②Stretching, stretching the cut raw material on a hydraulic stretching machine into a cylindrical shape. It will cause work hardening during the stretching process. If the depth of the cylinder is large, it is necessary to anneal the preform during multiple stretching processes to prevent cracking

It can be seen that the process is relatively complicated, especially the stretching process. Not only is the process cumbersome and the production efficiency is low, but also the equipment required is complicated and the input cost is high; Excision, resulting in waste of material

The formed cylindrical or conical preform is loaded into the expansion machine, filled with expansion fluid for expansion, since the preform is closed at this time, the process of exhausting is required during the hydraulic expansion process to avoid the gas from causing The problem of uneven molding, that is, the need to increase exhaust related devices and equipment, increases the investment cost

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