Re-screwdown process for head part of rough Mill

Abstract

The invention relates to a re-screwdown process for a head part of a rough mill, and belongs to the technical field of production devices for hot rolled plate belts in the metallurgy industry. According to the technical scheme, when the head part of a rolled piece arrives at the roller vertical center line of an upper working roller and a lower working roller of a first frame rough mill, downwardpressure is applied to the upper working roller of the first frame rough mill, so that the upper working roller of the first frame rough mill is continuously rolled after moving by a distance X whilethe upper working roller rotates; and when the head of the rolled piece reaches the vertical center line of an upper working roller and a lower working roller of a second frame rough mill, downward pressure is applied to the upper working roller of the second frame rough mill, so that the upper working roller of the second frame rough mill moves downwards by a distance 2X while the upper working roller rotates, and rolling is carried out again and again until rolling of a last rough rolling mill is finished. According to the re-screwdown process, under the condition that the rolling pass is not increased and the thickness of the initial rolled piece is reduced, the pass reduction of the rough mill is improved, the thickness of a middle blank is greatly reduced, and thin-specification stable rolling of a subsequent finish mill is facilitated.

Description

technical field [0001] The invention relates to a heavy-pressing process at the head of a roughing mill, and belongs to the technical field of hot-rolled strip production equipment in the metallurgical industry. Background technique [0002] In the conventional strip rolling process, the rolled piece needs to be rolled into an intermediate billet of required thickness in the roughing mill. Regardless of the reciprocating rolling or continuous rolling process, due to the large initial thickness of the rolled piece, and considering the small diameter of the work roll and the limitation of biting conditions (generally, the biting angle is limited to about 17°), the roughing mill The pressing capacity of each pass is limited. Once the reduction in the pass of the roughing mill exceeds a certain limit, accidents such as slipping and inability to bite will occur, which will affect the smooth running of the production line. As the current hot-rolled strip thickness specification ...

AI Technical Summary

Problems solved by technology

Regardless of the reciprocating rolling or continuous rolling process, due to the large initial thickness of the rolled piece, and considering the small diameter of the work roll and the limitation of biting conditions (generally, the biting angle is limited to about 17°), the roughing mill Reduction capacity per pass is limited

However, once the pass reduction of the roughing mill exceeds a certain limit, accidents such as slippage and inability to bite in will occur, which will affect the smooth running of the production line

As the current hot-rolled strip thickness specification tends to be thinner, in order to obtain a thinner intermediate billet in order to achieve thinner finish rolling; only increase the rolling passes of the reciprocating rough rolling or reduce the rolling The original thickness, this practice not only increases the production cost, but also reduces the production efficiency, which seriously limits the improvement of the competitiveness of the hot-rolled strip production line

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