A device and method for integrally forming a large annular shell part

Abstract

The invention provides a one-piece forming device and method for large-scale ring shell parts. The one-piece forming device for the large-scale ring shell parts comprises a concave die, a combined punch, and a blank holder; the combined punch comprises a punch and a reverse punch, the punch and the reverse punch are in clearance fit, and a gas spring is used for providing the pressure of the reverse punch and adjusting the distance between the reverse punch and a slab so that the punch and the reverse punch can move independently; the concave die is provided with a fluid medium passage, so that pressure fluid enters into a concave die cavity through the fluid medium passage and acts on the lower part of the slab to deform the slab; and the slab is positioned between the blank holder and the concave die. By adopting one-piece forming, digital control and mass production quality control are easily realized; and since conventional forming welding process is eliminated, the problems such as residual stress caused by the welding, unevenness of product performance, and contour sizing of a weld joint are resolved, and forming precision and service reliability of the large-scale ring shellparts are greatly improved.

Description

technical field [0001] The invention relates to the field of integral forming of large complex curved deep cavity components, in particular to the field of integral forming of large ring shell parts. Background technique [0002] The lip part of the aero-engine is a complex ring shell, which belongs to the thin-walled plate part with large complex space and curved surface. In order to meet the requirements of fluid dynamics and impact energy absorption under the high-speed flight conditions of aviation aircraft, the engine lip is usually made of high-strength aluminum alloy material, the wall thickness of the lip is generally less than 1.5mm, and the axis of the ring shell is an arc of non-uniform curvature. The structure of the longitudinal section is uneven, which is a typical ring shell plate part with complex variable cross-section. Such parts are usually formed by stamping in blocks and assembled and welded. The tailor-welded structure is as follows: figure 1 shown. ...

AI Technical Summary

Problems solved by technology

[0003] The main problems of tailor-welded forming method are: poor profile accuracy, joint difference at the weld seam; low forming efficiency / large calibration workload; low structural rigidity, poor strength at the weld seam; low material utilization rate, production high cost

The specific performance is as follows: 1) The accuracy of the shape contour is difficult to meet the design requirements. The existing forming method adopts stamping forming. Since the shape and size of each section of the ring shell are different, it is difficult to control the springback of the block stamping forming, and the springback of the ring shell section is the largest. More than 5.6mm, it is difficult to meet the design requirements (less than 0.8mm)

2) The lip material is 2xxx series aluminum alloy. The weld strength after tailor welding is generally 70% of the parent material, and the residual stress after welding is relatively large, which leads to uneven strength of the lip parts and is prone to failure at the weld. Reduced overall lip forming ability

3) There is an obvious step difference at the welding seam of the spliced ​​lip, which affects the accuracy of the lip outline, requires manual calibration, and the workload is heavy, and the surface quality of the lip parts is reduced

4) When block forming is adopted, the amount of residual material in the process is large, and the material utilization rate is less than 50%, resulting in serious waste of materials. At the same time, at least 8 forming processes are required for block forming, and multiple heat treatments are required in the middle, resulting in production efficiency. low / high production cost

Due to the poor plasticity of the material, when pure bulge forming is used, the maximum equivalent strain exceeds 30%, far exceeding the forming limit of the material, and multiple passes of intermediate annealing are required; for larger diameter engine lips, tailor-welded blanks are required. Cracks are prone to occur at the weld, making bulge forming difficult

[0005] The present invention provides an integral forming device and method for large ring shell parts to solve the problem of low profile accuracy, poor surface quality, low forming efficiency, large workload of shape correction, uneven strength of parts, Problems of low reliability, low material utilization and high cost, improve material forming limit and part forming accuracy, reduce part forming cost, and ensure good aerodynamic service performance of ring shell parts

Images