Thin-walled three-layer hollow structure member and method for controlling surface groove defect

Abstract

The invention discloses a method for controlling a surface groove defect of a thin-walled three-layer hollow structure member. The method for controlling the surface groove defect of the thin-walled three-layer hollow structure member comprises the following steps that (1), the two sides of a core plate are coated with welding stop agent patterns according to a design shape, and the inner sides oftwo sleeves are separately coated with welding stop agents; (2), outer covering skins and the bag sleeves are separately superimposed on the two sides of the core plate in sequence, the peripheral ofthe superimposed assembly is sealed, and an air channel is reserved between the core plate and the outer covering skins on both sides of the core plate; (3), diffusion bonding between the core plateand the outer covering skins is carried out on the assembly; (4), first step progressive super plastic forming is implemented; (5), second step progressive super plastic forming is implemented; and (6), the sleeves are removed to obtain the thin-walled three-layer hollow structure member. Meanwhile, the thin-walled three-layer hollow structure member is further disclosed. The technology blank design of the sleeves and a progressive forming control method are adopted to effectively reduce a surface groove of a three-layer structure, and the hollow structure member with surface quality meeting design requirements is obtained.

Description

technical field [0001] The invention relates to the technical field of titanium alloy manufacturing, in particular to a thin-walled three-layer hollow structure and a method for controlling surface groove defects. Background technique [0002] Super plastic forming (SPF) is a process method that uses the superplasticity of materials to form parts. The superplastic forming process can produce complex structures that are difficult to form by conventional processes, and there is no springback, which can ensure the accuracy of formed parts and good processing repeatability. Diffusion Bonding (DB) is a method that uses the surface of the material to be connected to form a connection through solid-state diffusion between atoms under the conditions of a pressure that is not enough to cause plastic deformation and a temperature lower than the melting point of the workpiece to be connected. [0003] If a material has both superplasticity and diffusion bonding characteristics, and th...

AI Technical Summary

Problems solved by technology

According to the number of layers required for the manufacture of the structure, the process structure can be divided into single-layer, two-layer, three-layer and four-layer structures. One of the difficulties in forming the three-layer structure is that surface groove defects are difficult to control. Skin thickness is used to reduce groove defects, so its structural weight increases, limiting its scope of use and structural design margin

In addition to increasing the thickness of the outer skin to reduce the groove, the groove can also be covered by the outer skin by increasing the number of layers of the sheet to five layers. However, the performance of the parts formed by this method is difficult to meet the design requirements

[0004] For the three-layer structure, based on engineering experience, usually the thickness of the outer skin is more than 3 times the thickness of the middle core plate to obtain parts without groove defects on the surface, and the thickness of the outer skin increases with the increase of the cavity height, and then through the surface Thinning treatment, remove the excess thickness of the outer skin to meet the design requirements, this method is a serious waste of materials, especially for parts with a high cavity height, there are many procedures and the process is complicated

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