Rolling and forming method for 0Cr25Ni20Mo2 stainless steel thin-wall ring

Abstract

The invention discloses a rolling and forming method for a 0Cr25Ni20Mo2 stainless steel thin-wall ring, aiming to roll and form the thin-wall ring with high forming size precision and good tissue and performance. The invention has the technical scheme that the method comprises the following steps of: firstly, sheathing a 0Cr25Ni20Mo2 stainless steel pre-rolled blank which is heated to deformation temperature and a preheated follow-up die sleeve into a ring rolling machine, sheathing the follow-up die sleeve into the pre-rolled blank, and positioning the two workpieces by using a home roll, a core roll, a snubber roll and upper and lower cone rolls of the ring rolling machine; then starting the ring rolling machine, and enabling core roll to make the feed movement along the radial direction towards the direction of the home roll and roll the pre-rolled blank together with the home roll by a rolling force of 150KN-2,900KN under the support of the follow-up die sleeve to make the pre-rolled blank broadened along the radial direction at the speed of 7mm / s-13mm / s so that the wall thickness of the pre-rolled blank is gradually reduced; and rolling the pre-rolled blank into the thin-wall ring after the deformation of the pre-rolled blank reaches 40-60 percent. The minimum wall thickness value of the 0Cr25Ni20Mo2 stainless steel thin-wall ring rolled and formed by the method is 25mm, and the maximum value of height-thickness ratio is 25mm. The ring is mainly used for a revolving body part used in oil gas field 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 0Cr17Ni12Mo2 stainless steel thin-walled ring. Background technique [0002] 0Cr17Ni12Mo2 stainless steel belongs to the austenitic stainless steel with type number 316 in ASTM A473-01 (R09) of the American Society for Testing and Materials. The steel thin-walled ring formed by rolling process requires high tensile properties and corrosion resistance. It is mainly used for rotary parts used in fields such as oil and gas. During rolling, due to the small deformation of the ring, the thinner wall thickness, and the higher requirements for dimensional accuracy, performance and structure, the difficulty of rolling and forming is increased. [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 bl...

AI Technical Summary

Problems solved by technology

When using this method to roll thin-walled 0Cr17Ni12Mo2 stainless steel 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 of the rolling die and the pre-rolled billet will Intense friction not only makes the rolling process very unstable and affects production, but also easily leads to the temperature rise of the pre-rolled billet, which affects the structure and properties of the steel, 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 0Cr17Ni12Mo2 stainless steel thin-walled rings, due to the rigidity of the core roll and other parts of the ring rolling machine In addition to the poor structural rigidity and small machining allowance of the thin-walled ring, 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 due to design use or machining requirements, which will cause certain losses to the 0Cr17Ni12Mo2 stainless steel material that is not cheap

[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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