Multistage Rolling Mill Layout for Coolant Space and Bearing Life
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Solution Overview
Problem
In six-high rolling mills using small-diameter work rolls for hard material rolling, there is a challenge in installing coolant spray headers and controlling coolant zone flow rates due to space constraints, leading to increased horizontal force on work rolls, which shortens the life of support bearings and poses risks of high load wear during strip breakages.
Innovation Solution
A multistage rolling mill design that includes offsetting work rolls and intermediate rolls to reduce horizontal force, using rotatable support bearings instead of fixed pads, and integrating coolant spray headers and cobble guards to manage coolant flow and strip shape, allowing for efficient high-speed rolling and improved product quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If support bearings and support pads are provided to support the entire length of small-diameter work rolls, then work roll stability is improved, but space for installing coolant spray headers and cobble guards is reduced
Solution Approach 1:
The support structure is divided into multiple support rolls arranged at different positions along the work roll length, rather than using continuous support pads. This segmentation provides discrete support points that maintain work roll stability while leaving gaps between support rolls for installing coolant spray headers and cobble guards.
Solution Approach 2:
The support system transitions from a two-dimensional continuous pad support to a three-dimensional arrangement of discrete support rolls positioned at specific locations, creating vertical support while maintaining horizontal clearance for coolant headers and cobble guards.
2Productivity
If rolling torque is increased to improve productivity, then output is improved, but horizontal force on work rolls increases, shortening support bearing life
Solution Approach 1:
The support function is segmented into multiple support rolls distributed along the work roll length, with each support roll carrying a portion of the load. This distribution reduces the horizontal force concentration on individual support bearings, extending their service life while enabling higher rolling torque for improved productivity.
Solution Approach 2:
Different support rolls are positioned at specific locations along the work roll to provide localized support where needed, optimizing the distribution of horizontal forces and reducing peak loads on individual support bearings during high-torque operation.
3Ease of manufacture
If fixed support pads are used to support work rolls, then installation simplicity is improved, but wear during strip breakage increases
Solution Approach 1:
The support system transitions from fixed support pads to rotatable support rolls that can rotate freely. During strip breakage or abnormal conditions, the rotatable support rolls can accommodate sudden load changes and instantaneous high loads without experiencing the same wear mechanisms as fixed pads, while maintaining installation simplicity.
Data Source
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AI summary
A multistage rolling mill 100 includes support bearings 10a, 10b, 10c, 10d, 10e, 10f, 10g, and 10h arranged on the entry side and/or the exit side of work rolls 2a and 2b, and supporting the work rolls 2a and 2b on an work side and a drive side. The offset positions in a pass direction of the pair of work rolls 2a and 2b for rolling a strip 1 are changed by moving in and out the support bearings 10a, 10b, 10c, 10d, 10e, 10f, 10g, and 10h to the entry side or the exit side with respect to the pass direction. A multistage rolling mill capable of rolling a hard material efficiently and suitable for obtaining a strip of high product quality is thereby provided.