Processing method of fine-grain superplastic TA15 titanium alloy medium-thickness plate

Abstract

The invention discloses a processing method of a fine-grain superplastic TA15 titanium alloy medium-thickness plate. The processing method comprises the following steps that 1, vacuum consumable arc melting is carried out to obtain a TA15 titanium alloy cast ingot; 2, after heat preservation, a primary forging stock is obtained through upsetting, drawing, cogging and forging; 3, after heat preservation, a second-stage forging stock is obtained through beta-phase region upsetting and drawing forging; 4, upsetting and drawing forging in an alpha + beta two-phase region is carried out to obtain afourth-stage forging stock; 5, a forge piece is obtained through upsetting, drawing and finish forging; 6, after heat preservation, a first-fire rolled plate blank is obtained through first-fire rolling; 7, after heat preservation, a second-fire rolled plate blank is obtained through second-fire rolling; and 8, the TA15 titanium alloy medium-thickness plate is obtained through annealing treatment. According to the processing method of the fine-grain superplastic TA15 titanium alloy medium-thickness plate, the corresponding deformation temperature is selected and combined with multi-heating-number large-deformation upsetting and drawing forging, so that the TA15 titanium alloy cast ingot with a coarse structure is crushed under the large deformation, driving force is provided for recrystallization, the grain refinement and homogenization degree is improved, and the fine-grain superplasticity TA15 titanium alloy medium-thickness plate is obtained.

Description

technical field [0001] The invention relates to the technical field of titanium alloy material processing, in particular to a method for processing fine-grained superplastic TA15 titanium alloy medium-thick plates. Background technique [0002] Because of its high superplasticity, fine-grained titanium alloy can be processed into thin-walled structural parts by superplastic forming, and can widely replace various precision castings and forgings of aircraft. To the obvious weight reduction effect, greatly increase the payload. This type of component generally has the characteristics of high rib and thin belly, complex shape, and large projected area, which requires high tissue performance. [0003] TA15 titanium alloy has good comprehensive mechanical properties, and its strength, fracture toughness, fatigue limit, and stress corrosion resistance are slightly higher than TC4 titanium alloy. Important structural parts with high height and complex stress have been widely used...

AI Technical Summary

Problems solved by technology

However, due to the large deformation resistance of titanium alloy, narrow deformation temperature range, and strong tissue sensitivity of TA15 titanium alloy, problems such as coarse grains and uneven structure are prone to occur during the plate preparation process, resulting in unstable quality of titanium alloy medium-thick plates and low yield. Low and low superplasticity, which limits the application of titanium alloy medium-thick plates in high-end fields

[0004] The traditional TA15 titanium alloy medium and thick plate processing technology usually adopts unidirectional rolling, the direction of the plate does not change during the rolling process, and the grains deform along one direction during the rolling process, resulting in large differences in the transverse and longitudinal microstructures , the plate processing streamline is obvious, and the surface of the plate will produce "corduroy groove" along the rolling direction

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