Thermal bulging method of high-nitrogen stainless steel conical ring rolled piece

Abstract

The invention discloses a thermal bulging method of a high-nitrogen stainless steel conical ring rolled piece. The method comprises the following steps that the hot-rolled conical ring rolled piece isenabled to sleeve the periphery of a preheated bulging block in a bulging machine, and a preheated pressing block is moved to be matched with the bulging block to be pressed on the upper end surfaceof the ring rolled piece; the bulging machine is started, so that the bulging block extrudes the ring rolled piece in the radial direction from the inner conical surface of the ring rolled piece, andmeanwhile, the pressing block synchronously extrudes the ring rolled piece in the axial direction, so that the plastic deformation occurs to the ring rolled piece so as to reach the preset size and complete bulging after pressure maintaining, wherein the plastic deformation comprises the situations that the inner diameter and the outer diameter of the ring rolled piece are expanded, the wall thickness is reduced, and the height is reduced; in the bulging process, the bulging temperature ranges from 820 DEG C to 920 DEG C, the bulging speed ranges from 0.62 to 1.64 mm / s, the pressing speed is 0.22 to 1.24 mm / s, and the pressure maintaining time is 42-84 s; and next, the ring rolled piece is rotated by 30 degrees along the central axis, then the bulging mark formed in the inner conical surface of the ring rolled piece in the bulging process is leveled through bulging according to the operation, and then sizing is completed. The size precision of the bulged ring rolled piece reaches + / -2mm, and the method is mainly applied to the fields of special engineering equipment and the like.

Description

technical field [0001] The invention relates to a bulging method for a ring, in particular to a thermal bulging method for a high-nitrogen stainless steel tapered ring rolling piece. Background technique [0002] The tapered ring rolling piece is a special-shaped ring rolling piece with a tapered longitudinal section, which is widely used in aviation, aerospace, gas turbines, special engineering equipment and other industries. Due to the difference in diameter between the upper and lower end surfaces of the tapered ring rolling piece, the difficulty of bulging is increased, and defects are prone to occur if the bulging process is not well controlled. [0003] The Chinese invention patent specification CN102513456A published on June 27, 2012 discloses a thermal expansion method for stainless steel special-shaped ring rolling parts. The ring surface is set on the periphery of the outer peripheral surface of the preheated bulging block, and the outer peripheral surface of the ...

AI Technical Summary

Problems solved by technology

[0004] When the above method is used to bulge the high-nitrogen stainless steel tapered ring-rolled piece, due to the difference in diameter between the upper and lower end surfaces of the tapered ring-rolled piece, most of the strain during bulging is concentrated on the small end surface of the tapered ring-rolled piece. After the bulging is completed, a slope will appear on the large end surface of the tapered ring rolling piece from the inner diameter to the outer diameter, and the inner wall of the tapered ring rolling piece will be concave in the middle position. If the bulging force is too large, it is easy to make the cone The ring rolling piece expands upwards to form a bulging block

That is to say, after the bulging of the tapered ring rolling piece, there will be problems such as warping deformation, inner wall depression, and low dimensional accuracy.

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