A Forming Method of Thin-Wall Twisted Tube with Large Cross-section Ratio and Triangular Section

Abstract

The invention discloses a forming method of a large-section-ratio triangular-section thin-wall twisted tube. The forming method aims at solving the problem that formation of a rounded corner is not in place due to limit rounded corner restraint to the small acute triangle section, and solving the problems of large section expansion amount difference and formation fracture caused by a large section change rate, so that qualified parts are formed and the production efficiency is improved. According to the adopted technical scheme, firstly, a weld joint is cut in the longitudinal direction after a plate is bent, and a triangular pyramid tube is obtained through longitudinal welding; secondly, the triangular pyramid tube is forged into a preformed part in the shape approximate to that of a finished part through a preforming mold, the preformed part is bent and twisted, and the large opening portion of the triangular pyramid tube is expanded to be in a conical shape; and thirdly, the preformed part is subjected to expansion formation after being subjected to annealing, an expansion formation mold adopts a female mold and a male mold, the male mold and the preformed part are identical in shape, the male mold stretches into a tube cavity of the preformed part before expansion formation is carried out, the mold is opened after expansion formation is carried out, technical sections at the two ends are cut off, and then the finished part is obtained.

Description

technical field [0001] The invention belongs to the field of aero-engine manufacturing, and relates to a sheet metal forming method, in particular to a forming method of a thin-wall twisted tube with a large cross-section ratio and a triangular cross-section. Background technique [0002] The material of the inner cold air duct of the new aero-engine high-pressure turbine guide is a nickel-based superalloy, see figure 1 , the wall thickness is 0.2mm, the length of the catheter is about 67mm, and its shape has bending and twisting along the length direction. Its cross section is approximately triangular, the minimum acute angle of the triangular section is only 24°, and the minimum transfer arc radius is only 1.1mm. The size of its cross-section varies greatly. The maximum side length of the section is about 30×23×14mm, and the circumference is 66mm. The minimum side length of the section is about 16×13×9mm, and the circumference is 37.5mm. [0003] Due to the small size of...

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Problems solved by technology

[0006] In order to solve the problems in the prior art, the present invention proposes a forming method for a thin-walled twisted tube with a larger cross-section than a triangular cross-section, which solves the problem of insufficient fillet forming of a small acute-angle triangular cross-section due to limit fillet constraints, and solves the problem The large difference in section expansion caused by the large section change rate and the problem of forming cracks can form qualified parts and improve production efficiency.

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