Thermal bulging process for rectangular stainless steel rolled ring workpieces

Abstract

Disclosed is a method for heat bulge forming a rectangular ring rolled piece of stainless steel. The method comprises the steps of: mounting the hot-rolled rectangular ring rolled piece of stainless steel (10) over the periphery of a pre-heated bulge-forming block (3) in a bulge-forming machine; starting the bulge-forming machine to press the bulge-forming block radially from the inner circumferential surface of the ring rolled piece against the ring rolled piece to complete a first bulge-forming step, the bulge-forming temperature being 890°C-950°C, the bulge-forming duration being 15 s-25 s, the duration for pressure maintenance being 7 s-8 s, and the deformation amount being 0.9%-1.2%; then rotating the ring rolled piece at 45° about the central axis to complete a first rotation; completing a second bulge-forming step according to the abovementioned operation, the bulge-forming temperature being 850°C-910°C, the bulge-forming duration being 15 s-25 s, the duration for pressure maintenance being 9 s-10 s, and the deformation amount being 0.7%-1%; rotating the ring rolled piece again in the direction of the first rotation to complete a second rotation; and conducting a third bulge-forming step according to the abovementioned operation, the bulge-forming temperature being 800°C-870°C, the bulge-forming duration being 25 s-35 s, the duration for pressure maintenance being 13 s-15 s, and the deformation amount being 0.5%-0.8%. The dimensional accuracy of the bulge-formed ring rolled piece can reach 10 / 00-20 / 00 of the corresponding dimensions.

Description

technical field [0001] The invention relates to a bulging method for a ring, in particular to a thermal bulging method for a stainless steel rectangular ring rolling piece. Background technique [0002] Stainless steel rectangular ring-rolled pieces (referring to the ring-rolled piece with a rectangular longitudinal section) are rolled by the ring rolling mill. Due to the limitation of the rolling process and equipment, the dimensional accuracy is generally not high; only when the shape of the ring-rolled piece is relatively Under the condition of ideal and excellent equipment performance, the dimensional accuracy can reach 3‰~5‰ (three thousandths to five thousandths) of the corresponding size, and the ring rolled parts after rolling are due to the large stress, and the follow-up If the processing process is not well controlled, defects such as warping, deformation and even cracking may easily occur. [0003] The Chinese invention patent specification CN101367104A publishe...

AI Technical Summary

Problems solved by technology

This method does not disclose in detail how to improve the dimensional accuracy of the ring through bulging, but it is generally concluded that the purpose of improving the forming accuracy of the retaining ring can be achieved, that is, this method cannot solve the problem of low dimensional accuracy of the ring rolling in the prior art The problem

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