Rolling Straightening Mill for One-Pass Pipe Diameter Reduction
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Solution Overview
Problem
Conventional methods for outer-diameter reduction and straightening of pipes or tubes require separate devices, leading to high costs, longer processing times, and uneven strain distribution, resulting in bending and compromised dimensional accuracy.
Innovation Solution
A rolling straightening machine with at least two rollers, where the outer-diameter-reducing rolling portion narrows from upstream to downstream and the straightening rolling portion widens, ensuring symmetrical and asymmetrical shapes to maintain pass line straightness and induce necessary bending for accurate diameter reduction and straightening in a single apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If outer-diameter-reducing rolling and straightening rolling are performed using different devices, then each process can be optimized independently, but apparatus cost, operation cost, and processing time increase significantly
Solution Approach 1:
The patent combines outer-diameter-reducing rolling and straightening rolling into a single rolling mill device. The rolling mill includes a rolling groove with an inclined surface for diameter reduction and a straightening rolling portion with asymmetric surfaces for straightening, allowing both functions to be performed simultaneously on pipe or tube materials in one apparatus, thereby reducing the number of devices required while maintaining manufacturing precision
Solution Approach 2:
The rolling mill is designed with multi-functionality to perform both outer-diameter reduction and straightening operations. The rolling groove structure incorporates both the inclined surface for diameter reduction and the straightening rolling portion with asymmetric surfaces, enabling a single device to execute multiple functions that traditionally required separate specialized equipment
2Productivity
If conventional separate rolling mills are used, then each process can be performed with dedicated equipment, but production cost and processing time increase
Solution Approach 1:
By merging outer-diameter-reducing rolling and straightening rolling into one simultaneous operation within a single rolling mill, the patent eliminates the sequential processing required by conventional separate devices. This integration allows both functions to be performed in one pass through the rolling mill, significantly reducing total processing time and improving productivity
Solution Approach 2:
The rolling mill design enables continuous useful action by performing diameter reduction and straightening in a continuous simultaneous process. The material passes through the rolling groove once and receives both diameter reduction and straightening treatments continuously, eliminating idle time and conveyance time between separate operations
3Manufacturing precision
If inclined rolling mill is used for outer-diameter reduction, then diameter can be reduced, but uniform strain distribution is difficult to achieve due to friction differences, leading to bending
Solution Approach 1:
The patent applies asymmetry principle in the straightening rolling portion where the rolling surfaces are deliberately made asymmetric with respect to the pass line. This asymmetric design compensates for the non-uniform strain distribution caused by friction differences in the inclined rolling portion, allowing the material to bend in a controlled manner during straightening and achieving both uniform strain distribution and dimensional accuracy
Solution Approach 2:
The rolling groove is designed with different local qualities: the inclined surface portion has specific characteristics for diameter reduction, while the straightening rolling portion has asymmetric surfaces with different radii of curvature tailored for straightening. Each portion is optimized for its specific function, with the asymmetric straightening portion compensating for non-uniformities introduced in the diameter reduction zone
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
Enables high-speed, high-accuracy outer-diameter reduction and straightening in a single apparatus, reducing production costs and processing time while maintaining dimensional accuracy and correcting bending issues.
Implementation Method 1
when a pipe or tube material or a bar material is subjected to outer-diameter-reducing rolling or the like to apply plastic strain
Implementation Method 2
the pipe or tube material or the bar material is subjected to bending-bend restoration working in its axial direction using a straightening rolling mill which is different from the outer-diameter-reducing rolling mill to remove the bending
Data Source
AI summary
Provided is a rolling straightening machine which enables outer-diameter-reducing rolling and straightening rolling of a pipe or tube material or a bar material at high speed with high accuracy. The rolling straightening machine includes at least two rollers arranged across a pass line of a pipe or tube material or a bar material, the at least two rollers having a gap therebetween, the gap being defined by an outer-diameter-reducing rolling portion having a diameter reduced from an upstream side toward a downstream side in the rolling straightening machine and a straightening rolling portion continuous from an exit side of the outer-diameter-reducing rolling portion toward a downstream side of the rolling straightening machine, the rollers having shapes which are symmetrical about the pass line in the outer-diameter-reducing rolling portion, and in the straightening rolling portion, asymmetrical to the pass line in the outer-diameter-reducing rolling portion.