Hot bulging method for hot work die steel taper shaped ring rolled piece

Abstract

The invention discloses a hot bulging method for a hot work die steel taper shaped ring rolled piece. The method includes the following steps: the hot rolled conical ring rolled piece is sleeved by the periphery of a preheated bulging block in a bulging machine, and a preheated pressing block is moved, cooperates with the bulging block and presses the upper end face of the ring rolled piece; the bulging machine is started to make the bulging block press the ring rolled piece from the inner conical surface of the ring rolled piece along a radial direction, the pressing block synchronously presses the ring rolled piece along the radial direction to cause plastic deformation of inner and outer diameter size expansion, wall thickness reduction and height reduction to reach predetermined dimensions, and the bulging is completed after pressure holding, wherein the bulging temperature is 840-920 DEG C, the bulging speed is 0.63-1.63 mm / s, the pressing speed is 0.23-1.23 mm / s and the pressureholding time is 43-83 s during the bulging; and then the ring rolled piece rotates 30 degree along the central axis, and the protruding marks formed on the inner conical surface of the ring rolling piece during the bulging process are flattened by bulging according to the steps to complete shape verification. The dimensional accuracy of the ring rolled piece after the bulging is high, and the ringrolled piece is mainly used in the fields of special vehicles 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 tapered ring rolled piece of hot work die steel. Background technique [0002] The hot work die steel tapered ring rolling piece is a special-shaped ring rolling piece with a tapered longitudinal section, which is mainly used in special vehicles and other industries. Due to the difference in diameter between the upper and lower ends 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 prior art discloses a thermal bulging method for stainless steel special-shaped ring rolling parts. The technical solution is: put the hot-rolled stainless steel special-shaped ring rolling parts into the bulging machine, so that the inner ring surface is covered by the preheated expansion The periphery of the outer peripheral surface of the shaped block, the ...

AI Technical Summary

Problems solved by technology

[0004] When the above method is used to bulge hot-worked die steel tapered rings, due to the difference in diameter between the upper and lower ends of the tapered ring, most of the strain during bulging is concentrated on the small end of the tapered ring. 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 a concave phenomenon will appear in the middle of the inner wall of the tapered ring rolling piece. If the bulging force is too large, it is easy to break the cone The rolling piece of the ring bulges 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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