Roll forming method of TC25 titanium alloy thin-walled ring forging

Abstract

The invention discloses a roll forming method of a TC25 titanium alloy thin-walled ring forging. In order to roll-form a thin-walled ring forging with high dimensional precision and excellent tissue and performance, the technical scheme comprises the steps of: firstly, sleeving a preheated follower die sleeve and a titanium alloy pre-rolled blank heated to a deformation temperature in a ring rolling mill, sleeving the follower die sleeve in the pre-rolled blank, and positioning the two workpieces by using a main roll, a core roll, clutching rolls, an upper cone roll and a lower cone roll of the ring rolling mill; and starting the ring rolling mill, making a feeding motion by the core roll towards the direction of the main roll along the radial direction and rolling the pre-rolled blank at a rolling force of 200-4000KN under the support of the follower die sleeve by the core roll together with the main roll to ensure that the pre-rolled blank expands radially at a speed of 5-10mm/s, wherein the wall thickness is gradually reduced, and the pre-rolled blank is rolled into the thin-walled ring forging when the deformation reaches 25-45 percent. The minimum value of the wall thickness of the titanium alloy thin-walled ring forging roll-formed by adopting the method is 25mm, the maximum value of the height-thickness ratio is 25mm, and the ring forging is mainly used for gyrorotor parts, such as a cylindrical shell and the like used in the fields, such as aerospace and the like.

Description

technical field [0001] The invention relates to a rolling forming method of a ring forging, in particular to a rolling forming method of a TC25 titanium alloy thin-walled ring. Background technique [0002] TC25 titanium alloy is a martensitic two-phase heat-strength titanium alloy. The alloy elements are tin and tungsten, so that the alloy has good heat strength and heat resistance. It is used in aerospace and other fields for ring rolling forming. Rotary parts such as cylindrical shells, such as thin-walled rings such as aero-engine spacers, require a working time of more than 6000h at a temperature below 500°C, and a working time of more than 3000h at a temperature below 550°C. During rolling, due to the small amount of deformation of the alloy, the wall thickness of the forging is thin, the requirements for dimensional accuracy, performance and structure are high, and the alloy must meet the requirements of high reliability and low manufacturing cost, which increases the...

AI Technical Summary

Problems solved by technology

When using this method to roll thin-walled TC25 titanium alloy thin-walled rings, since the rolling die is fixed on the roll (that is, the main roll and the core roll), the gap between the pass shape of the rolling die and the pre-rolled billet during rolling The intense friction between them not only makes the rolling process very unstable and affects the production, but also easily leads to the temperature rise of the pre-rolled slab, which affects the structure and properties of the alloy, such as defects such as structure variation and coarse grains.

[0004] When using the above method and directly using the main roll and core roll of the ring rolling machine to roll (such as the ring rolling blank in the above method) thin-walled TC25 titanium alloy thin-walled rings, due to the rigidity of the core roll and other parts of the ring rolling machine Influenced by the thin-walled ring, coupled with poor structural rigidity and small machining allowance, it is easy to cause plastic instability of the pre-rolled billet during the rolling process, resulting in flattening, bell mouth, etc., resulting in the shape and size of the ring not reaching It is scrapped until the design use or machining requirements, which is a big loss for expensive titanium alloy materials

[0005] During the rolling process, when the pre-rolled slab is first rolled, the rolls are shifted to one side of its rotation direction, and then to the other side, so that the pre-rolled slab has a tendency to move toward its other side during the rolling process. The holding rollers on both sides swing left and right, affected by the reaction force generated by the holding rollers, the rings are easily crushed and scrapped

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