Traction Mandrel Rolling Mill for Stable Seamless Tube Forming
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Solution Overview
Problem
Existing rolling mills for seamless tubes face issues with mandrel stability, dimensional tolerance deterioration, and high maintenance costs due to the use of push bar systems, which require extensive guides and rails, leading to twisting and safety risks.
Innovation Solution
A rolling mill design that uses traction on the mandrel to move both the mandrel and the tubular blank through mill stands and dies, eliminating the need for push bars and associated guides, and incorporating a switchable operating head with rocker arms to facilitate smooth translation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a push bar system is used to move the mandrel through mill stands, then the mandrel can be pushed through the rolling section, but the mandrel stability deteriorates and twisting occurs
Solution Approach 1:
Instead of pushing the mandrel from behind using a push bar, the invention applies traction by pulling the mandrel from the front end through the mill stands. This inversion of the force application direction eliminates the instability and twisting caused by push bar compression, while maintaining the ability to move the mandrel through the rolling section.
Solution Approach 2:
The invention removes the push bar system and its associated guides and rails from the rolling mill. By extracting this problematic component, the mandrel stability issue and twisting are eliminated, and the system is simplified to use only traction-based movement without requiring extensive containment structures.
2Reliability
If extensive guides and rails are installed to contain the push bar and mandrel, then the mandrel can be contained during pushing, but the device complexity and maintenance costs increase
Solution Approach 1:
The invention removes the complex system of guides and rails that were necessary to contain the push bar and mandrel during pushing. By extracting this extensive containment structure, the device complexity and maintenance costs are significantly reduced while the mandrel is contained only during the rolling operation itself, not during movement.
Solution Approach 2:
The invention replaces the complex mechanical containment system (guides and rails) with a simpler traction-based movement system. The mandrel is pulled through the mill stands without requiring extensive guiding infrastructure, substituting a complex mechanical containment system with a simpler traction mechanism.
3Force
If a push bar of length greater than the mandrel is used, then the mandrel can be pushed through, but the system length and safety risks increase
Solution Approach 1:
Instead of using a long push bar that extends beyond the mandrel length, the invention inverts the approach by using a traction system that pulls the mandrel from the front. This eliminates the need for a push bar longer than the mandrel, reducing the system length and associated safety risks while maintaining the capability to move the mandrel through the rolling section.
4Productivity
If the mandrel is moved by pushing, then the blank can be fed through the mill stands, but dimensional tolerances deteriorate due to twisting
Solution Approach 1:
The invention inverts the movement method from pushing to traction-based pulling. This inversion prevents the mandrel twisting that occurs during pushing, thereby maintaining dimensional tolerances of the tubular element while still enabling the blank to be fed through the mill stands and processed efficiently.
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 design enhances safety, reduces maintenance and installation costs, improves dimensional tolerances, and increases versatility by allowing easy diameter changes without complex rail adjustments, while minimizing twisting and side loads on mill stands.
Implementation Method 1
moving means structured so as to move the mandrel and the blank along the rolling axis and through the mill stands or rolling dies in succession by traction on the mandrel
Data Source
AI summary
A rolling mill for rolling hollow or, in all cases, concave rod-shaped bodies, in particular tubes, in particular seamless tubes, said rolling mill comprising a rolling section (10) with a plurality of mill stands and/or rolling dies (11) arranged in succession to define a rolling axis Y, said rolling mill further comprising moving means for moving a mandrel (20) and a tubular blank (21) fitted onto an end portion (22) of said mandrel (20) along said rolling axis and through said mill stands or rolling dies (11) in succession; wherein said moving means are structured so as to move said mandrel (20) and said blank (21) along said rolling axis Y and through said mill stands or rolling dies (11) in succession by applying a traction on said mandrel.