High Modulus Work Rolls for Six-High Rolling Mill
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Solution Overview
Problem
Conventional rolling mills face challenges in rolling hard materials due to large work roll diameters, which result in poor thickness reduction, surface gloss, and difficulty in handling heavy loads, especially when using six-high or four-high mills without support rolls inside the rollable strip width, and those with support rolls outside face issues with bearing size and rigidity.
Innovation Solution
The use of a six-high or four-high rolling mill with work rolls made of high modulus longitudinal elasticity material, driven by upper and lower intermediate rolls and back-up rolls, without support rolls inside or outside the rollable strip width, allowing for a smaller work roll diameter within specific limits, expressed by equations, and utilizing composite materials for enhanced flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If work rolls with conventional material are used in six-high or four-high mills without support rolls inside the rollable strip width, then the structure is simplified, but the work roll diameter becomes too large (380mm minimum), imposing heavy loads and failing to ensure necessary thickness reduction
Solution Approach 1:
The patent changes the material parameter (modulus of longitudinal elasticity) of the work roll from conventional steel to high-modulus material, enabling the work roll to maintain sufficient rigidity at a smaller diameter. This resolves the contradiction by allowing simplified mill structure while achieving necessary thickness reduction capability.
Solution Approach 2:
The patent employs composite material construction for work rolls, combining a core material with a surface layer of high-modulus material. This composite structure provides both the mechanical strength needed for heavy loads and the high rigidity required for small diameter, thereby enabling productivity improvement without increasing device complexity.
2Ease of manufacture
If work rolls with conventional material are used, then material availability is good, but the work roll diameter must be large (380mm minimum), resulting in poor surface gloss on rolled strips
Solution Approach 1:
The patent uses composite material construction where the work roll surface layer is made of high-modulus material while the core can be conventional material. This maintains ease of manufacture through availability of conventional core materials while the high-modulus surface layer ensures small diameter operation and excellent surface gloss quality.
Solution Approach 2:
The patent applies local quality by using high-modulus material specifically at the work roll surface where it contacts the strip, while the core can use conventional materials. This localized application of high-modulus material improves surface gloss quality without requiring complete material replacement, maintaining ease of manufacture.
3Productivity
If support rolls are added inside the rollable strip width to enable smaller work roll diameter, then thickness reduction capability improves, but the space for support roll portion is small making it difficult to ensure sufficient strength and rigidity
Solution Approach 1:
The patent extracts the support function from separate support rolls and integrates it into the work roll itself through high-modulus material. This eliminates the need for support rolls inside the rollable strip width, avoiding space constraints while maintaining sufficient strength and rigidity for small diameter operation.
4Ease of operation
If support bearings are provided outside the rollable strip width, then support function is provided, but the upper and lower support bearings being of the same phase prevents use of large bearings, limiting ability to handle heavy loads and high torque rolling of hard materials
Solution Approach 1:
The patent extracts the support function from external support bearings and integrates it into the work roll through high-modulus material construction. This eliminates the constraint of same-phase bearing arrangement and enables the mill to handle heavy loads and high torque rolling of hard materials with smaller work roll diameter.
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
This configuration ensures reduced edge drops, improved surface gloss, and decreased minimum rollable strip thickness, enabling high productivity and handling of heavy loads in rolling hard materials, particularly suited for cold rolling.
Implementation Method 1
a material having a high modulus of longitudinal elasticity is used for the work roll
Data Source
Figure 1
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AI summary
A six-high rolling mill includes paired upper and lower work rolls (2) for rolling a strip (1) , paired upper and lower intermediate rolls (3) for supporting the paired upper and lower work rolls, and paired upper and lower back-up rolls (4) for supporting the paired upper and lower intermediate rolls, the six-high rolling mill having no supporting rolls inside and outside the reliable strip width of the work rolls. A similar four-high rolling mill lacks the intermediate rolls. In the six- or four-high rolling mill, the work rolls are driven, and the work rolls have a small diameter, and use a material having a high modulus of longitudinal elasticity, such as a cemented carbide or a ceramic.