Rolling and forming method of cobalt-base superalloy high cylindrical ring forging

Abstract

The invention discloses a rolling and forming method of a cobalt-base superalloy high cylindrical ring forging, which is used for rolling and forming the high cylindrical ring forging with thin wall and excellent texture and performance. The technical scheme of the rolling and forming method is as follows: putting a preheated follow-up die sleeve and a pre-rolled titanium alloy blank which is heated at deformation temperature into a ring rolling mill; positioning two workpieces by the main roller, the core roller, the snubber rollers, the upper cone roller and the lower cone roller of a ring rolling mill; then, starting the ring rolling mill; carrying out feed movement on the core roller of the ring rolling mill toward the main roller along with the radial direction; rolling a pre-rolled blank in the follow-up die sleeve at the rolling force of 420-4600KN by the core roller and the main roller to cause the pre-rolled blank to widen at the speed of 2-10mm / s along with the radial direction; and when wall thickness is gradually reduced and after the deformation amount of the re-rolled blank is 20-40%, rolling the re-rolled blank into the high cylindrical ring forging, wherein an upper cone roller, a lower cone roller and two snubber rollers do not move outwards along with the radial widening direction of the pre-rolled blank. The minimum wall thickness of the titanium alloy high cylindrical ring forging rolled and formed by the method is 25mm, and the maximum height to thickness ratio is 25mm. The cobalt-base superalloy high cylindrical ring forging is mainly used for revolved body parts, such as cylinders and the like used in the fields of 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 cobalt-based superalloy high-tube ring forging. Background technique [0002] Rotary components used in aerospace and other fields made of cobalt-based superalloys, such as forgings for afterburning cylinders, etc., due to the thinner wall thickness and higher height of the forgings, and the dimensional accuracy, performance and organizational requirements of the forgings. Higher, increasing the difficulty of rolling forming. [0003] The Chinese invention patent specification CN 101279346A published on October 8, 2008 discloses a rolling forming method of a nickel-based superalloy special-shaped ring forging. Second rolling ring billet (without using rolling die), and then put the billet into the ring rolling machine rolling die for rolling and forming, by adopting the method of small deformation forming in the two consecutive ring roll...

AI Technical Summary

Problems solved by technology

When this method is used to roll a cobalt-based high-temperature alloy high-tube ring forging with a thinner wall thickness, because the rotation direction of the main roll is inconsistent with that of the pre-rolled billet, the gap between the pass shape of the rolling die and the pre-rolled billet during rolling is inconsistent. Intense friction not only makes the rolling process very unstable and affects production, but also easily leads to an increase in the temperature of the pre-rolled billet, which affects the structure and properties of the alloy, such as defects such as structure variation and coarse grains.

[0004] When adopting the above-mentioned method and directly using the main roll and the mandrel roll of the ring rolling machine to roll (as the ring rolling blank in the above-mentioned method) thin-walled cobalt-based superalloy high-tube ring forgings, due to the main roll of the ring rolling machine Influenced by the rigidity of other components, coupled with the poor structural rigidity and small machining allowance of thin-walled high-tube ring forgings, it is easy to cause plastic instability of the pre-rolled billet during the rolling process, resulting in flattening and bell mouth, etc., resulting in The shape and size of ring forgings cannot meet the design requirements or machining requirements and are scrapped, which is a great loss for expensive cobalt-based superalloy materials

Moreover, since the upper and lower tapered rolls and the two holding rolls will move outward with the radial expansion of the pre-rolled billet during rolling, the difficulty of equipment operation and control will be increased.

[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 left and right swing of the holding rolls on both sides is affected by the reaction force generated by the support of the holding rolls, and the ring forgings are easily flattened and scrapped

Moreover, since the size of the holding roll of the ring rolling machine is fixed, its height is generally not as high as that of the high-tube ring forging. "rolling" to form step traces, which will adversely affect the shape and dimensional accuracy of ring forgings

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