Isothermal forming die of large-curvature titanium alloy covering part and forming method of isothermal forming die

Abstract

The invention relates to an isothermal forming die of a large-curvature titanium alloy covering part. The structure of the isothermal forming die is as follows: a blank holder is arranged between a convex die and a concave die; the lower surface of the blank holder is matched with the molded surface of the convex die; the upper surface of the blank holder is matched with the molded surface of the lower surface of the concave die; the bottom surface of the blank holder is connected with the upper surface of the convex die through a push rod; a limiting groove is formed in the side face of the blank holder and is in sliding connection with the outer edge of a guide structure on the convex die; the upper surface of the blank holder fits the lower surface of the concave die; a guide plate is arranged at the lateral end of the concave die and is in sliding connection with an inner edge groove of the guide structure; a straight pin is arranged on the upper surface of the blank holder and is positioned in a limiting hole of the concave die. The isothermal forming die of the large-curvature titanium alloy covering part provides the effective die for preliminary isothermal forming steps and ensures the final forming of the large-curvature titanium alloy covering part; in addition, according to a forming method of the isothermal forming die, the processing steps of isothermal forming and superplastic forming are sequentially adopted, so that a formed hypocrateriform part is uniform in wall thickness and meets the technical requirements.

Description

technical field [0001] The invention relates to an isothermal forming die for large-curvature titanium alloy skin parts and a forming method thereof, belonging to the field of plastic forming of sheet metal. Background technique [0002] In my country's aviation sheet metal manufacturing, a variety of manufacturing processes for titanium alloy sheets have been promoted and applied. Due to its low density, high specific strength and specific fracture toughness, good fatigue strength and crack growth resistance, good low temperature toughness, strong corrosion resistance and other excellent comprehensive properties, titanium alloys are widely used in aviation, aerospace, shipbuilding and other industrial sectors. Since it is difficult to form titanium alloy sheet metal parts by conventional cold working methods, isothermal hot forming and superplastic forming methods are often used. Isothermal thermoforming refers to a pressure processing technology that heats metal materials...

AI Technical Summary

Problems solved by technology

[0003] The large curvature TC4 titanium alloy skin part is two pieces of aircraft pod skin, such as figure 1 The two split parts shown are directly superplasticized by using a single-layer plate with a thickness of δ1.8mm. Because the curvature is too large, it is difficult for the plate to flow due to friction at the first place where the film is applied, and the thinning basically stops. The material is difficult to replenish, and the purpose of material flow and filling can only be achieved by thinning the thickness. In the end, the material at the film sticking part is excessively thinned, figure 1 The thinning points at points 3 to 6 in the center exceed the tolerance requirements, and the thinning points 3 and 4 are the most serious, which do not meet the design requirements

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