Six-High Rolling Mill Work Roll Rigidity via High Modulus Materials
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Solution Overview
Problem
Conventional six-high rolling mills face challenges in rolling hard materials due to large work roll diameters, which result in high loads, poor gloss, and insufficient strength and rigidity, as well as issues with bearing marks and limited capacity for heavy load, high torque rolling.
Innovation Solution
A six-high rolling mill with work rolls made of high longitudinal modulus materials, such as tungsten carbide or ceramic, and a tandem rolling mill configuration that eliminates support rolls inside and outside the rollable strip width, allowing for smaller work roll diameters and improved flexural rigidity, reducing edge drops and enhancing surface gloss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional work rolls with standard material are used in a six-high mill without support rolls, then the structure is simplified, but the work roll diameter becomes too large (180-380 mm) causing heavy load and insufficient thickness reduction
Solution Approach 1:
The patent changes the material parameter (modulus of longitudinal elasticity) from conventional values to high-modulus materials, enabling work rolls with smaller diameters while maintaining structural integrity and reducing the load on rolling mill components
Solution Approach 2:
The patent employs composite or advanced material structures with high modulus of longitudinal elasticity, combining materials that provide both the necessary rigidity for small diameter rolls and the durability required for heavy load rolling operations
2Weight of moving object
If support rolls are added inside the rollable strip width to reduce work roll diameter, then the work roll size can be reduced, but the space for support roll portion is small making it difficult to ensure sufficient strength and rigidity
Solution Approach 1:
The patent changes the material parameters of support rolls to high-modulus materials, enabling the use of smaller diameter support rolls that fit within the limited space inside the rollable strip width while maintaining sufficient strength and rigidity through the enhanced material properties
3Ease of operation
If support bearings are provided inside the rollable strip width to support support rolls, then support rolls can be positioned, but bearing marks are transferred to or produced in the strip via the support rolls and work rolls
Solution Approach 1:
The patent extracts or removes the support bearings from the interior region inside the rollable strip width and relocates them to the exterior region, eliminating the source of bearing marks that would otherwise be transferred to the strip surface through the support rolls and work rolls
4Object-generated harmful factors
If supporting bearings are provided outside the rollable strip width, then bearing marks are avoided, but the upper and lower supporting bearings being of the same phase prevents use of large size bearings, limiting capacity for heavy load, high torque rolling
Solution Approach 1:
The patent applies asymmetric positioning to the upper and lower supporting bearings outside the rollable strip width, setting them at different phases (angular positions) rather than symmetrically at the same phase. This asymmetric configuration enables the use of larger size bearings with higher load capacity while maintaining the benefit of avoiding bearing marks on the strip surface
5Productivity
If work rolls with smaller diameter are used to increase productivity and reduce thickness, then high productivity is achieved, but the load on the rolling mill increases
Solution Approach 1:
The patent changes the material parameters of work rolls to high-modulus materials, enabling the use of smaller diameter work rolls that can achieve greater thickness reduction and higher productivity while the enhanced material strength compensates for the increased stress concentrations, allowing the system to handle the higher loads without failure
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The use of high longitudinal modulus materials ensures increased flexural rigidity, allows for smaller work roll diameters, improves surface gloss, and enables high productivity and quality rolling of hard materials with reduced minimum strip thickness and increased load capacity.
Implementation Method 1
the work roll uses a material having a high modulus of longitudinal elasticity (i.e., longitudinal modulus)
Data Source
AI summary
A rolling mill, which can use work rolls of a smaller diameter for rolling a hard material and a thin strip material, and can obtain strips of high product quality with high productivity, is provided. For this purpose, a six-high rolling mill includes upper and lower work rolls (2) as a pair for rolling a strip (1), upper and lower intermediate rolls (3) as a pair for supporting the paired upper and lower work rolls, and upper and lower back-up rolls (4) as a pair for supporting the paired upper and lower intermediate rolls, but has no supporting rolls inside and outside the rollable strip width of the work rolls. The work rolls have a small diameter, and use a material having a high longitudinal modulus, such as a hard metal or a ceramic.