Method for rolling and shaping structural steel high cylindrical ring forged piece

Abstract

The invention discloses a method for rolling and shaping a structural steel high cylindrical ring forged piece. The method is used for rolling and shaping the high cylindrical ring with thin wall and excellent texture and performances. The technical scheme is as follows: firstly sheathing a preheated follow-up die sleeve and a structural steel pre-rolled billet which is heated to the deformation temperature into a ring rolling mill, and positioning two workpieces through a main roller, a core roller, holding rollers, an upper conical roller and a lower conical roller of the ring rolling mill; and further starting the ring rolling mill, enabling the core roller to do feed motion to the main roller along the radial direction, rolling the pre-rolled billet in the follow-up die sleeve by 180KN-3800KN rolling force together with the main roller, enabling the pre-rolled billet to expand the width along the radial direction at the speed of 6mm / s-15mm / s and gradually reduce the wall thickness, and rolling the pre-rolled billet into the high cylindrical ring forged piece after the deformation amount achieves 30%-50%, wherein the upper and the lower conical rollers and the two holding rollers can be prevented from moving outwards along with the radial width expansion of the pre-rolled billet during rolling. The minimum value of the wall thickness of the structural steel high cylindrical ring forged piece which is rolled and shaped by adopting the method is 25mm, the maximum value of the height-thickness ratio is 25mm, and the forged piece is mainly used for cylindrical housings and other rotary parts used in the fields of aviation, spaceflight 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 high cylinder ring forging of structural steel. Background technique [0002] Rotary parts used in aerospace and other fields made of structural steel, such as cylindrical shell forgings, etc., due to the thinner wall thickness and higher height of the forgings, and the higher dimensional accuracy, performance and organizational requirements of the forgings , increasing the difficulty of roll forming. [0003] Chinese Invention Patent Specification CN 101279343A published on October 8, 2008 discloses a rolling forming method for stainless steel special-shaped ring forgings. In this method, alloy bars blanked according to specifications are subjected to upsetting, punching, and ring rolling to form billets. (No rolling die is used), and then the billet is put into the rolling die of the ring rolling machine for rolling and forming. By con...

AI Technical Summary

Problems solved by technology

When this method is used to roll high-tube ring forgings of structural steel with thinner wall thickness, since the rotation direction of the main roll is inconsistent with that of the pre-rolled billet, there will be a fierce gap between the pass shape of the rolling die and the pre-rolled billet during rolling. The friction not only makes the rolling process very unstable and affects production, but also easily leads to the rise of pre-rolled billet temperature, 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 rolling ring billet in the above method) thin-walled structural steel high-tube ring forgings, due to the main roll and other parts of the rolling ring machine The influence of rigidity, coupled with the poor structural rigidity and small machining allowance of thin-walled high-tube ring forgings, may easily lead to plastic instability of pre-rolled blanks during the rolling process, resulting in flattening, bell mouth, etc., resulting in ring forgings The shape and size do not meet the design use or machining requirements and are scrapped, resulting in waste of 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, so the reaction of the holding roll during the rolling process is likely to appear on the outer peripheral surface of the ring forging "and form step traces, which will adversely affect the shape and dimensional accuracy of ring forgings

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