Cold Pilger Mill Layout for Rolling 30 m Long Tubes
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Solution Overview
Problem
Conventional cold pilger rolling mills are limited in manufacturing long, high-quality metal tubes with uniform wall thickness and surface quality, as they can only handle hollows up to 15 meters in length, making it costly and inefficient to produce tubes exceeding this length.
Innovation Solution
A cold pilger rolling mill design with a movable roll stand and feed clamping carriage system, featuring a mandrel thrust block arrangement that allows for a minimum distance of 30 meters between the front and rear chuck positions, enabling the processing of hollows up to 30 meters or more, along with a coiling device for space-saving tube coiling and uncoiling, and a mandrel bar with high tensile strength to handle the necessary forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional cold pilger rolling mills are used, then manufacturing of hollows up to 15 meters is feasible, but production of longer tubes becomes costly and inefficient
Solution Approach 1:
The rolling mill is divided into multiple independent workstations (first workstation with first roll stand, second workstation with second roll stand) that can operate simultaneously on different sections of the hollow. This segmentation allows parallel processing of multiple tube sections, enabling efficient production of long tubes exceeding 15 meters by dividing the total length across multiple workstations.
2Length of stationary object
If the roll stand is made movable to increase working distance, then processing of longer hollows is enabled, but device complexity increases
Solution Approach 1:
The roll stand is designed with movable components including a movable roller that can be adjusted along the hollow, and a movable mandrel that can be positioned at different locations. This dynamic configuration allows the distance between the chuck and mandrel to be varied according to the hollow length, enabling processing of longer hollows up to 30 meters or more while maintaining operational flexibility.
3Strength
If mandrel bar with high tensile strength is used, then handling of long hollows is enabled, but material cost increases
Solution Approach 1:
The mandrel bar is designed with varying cross-sectional dimensions along its length, with the diameter being largest at the center and gradually decreasing toward the ends. This local quality variation optimizes the strength distribution to match the stress profile during hollow processing, providing sufficient tensile strength for handling long hollows up to 30 meters while minimizing material usage and cost.
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 the efficient and cost-effective production of long, high-quality metal tubes with uniform dimensions by allowing the processing of hollows up to 30 meters or more, reducing operational costs and maintaining high surface quality through continuous operation and efficient material handling.
Implementation Method 1
an extended hollow cylindrical blank is typically cold reduced in the entirely cooled state by compressive stresses
Implementation Method 2
the blank is cold reduced in the entirely cooled state by compressive stresses
Implementation Method 3
the feed chuck releases or clamps the hollow
Implementation Method 4
the chuck of the front mandrel thrust block is openable in a radial direction, so that a hollow is feedable between the chuck and the mandrel bar
Data Source
AI summary
A cold pilger rolling mill including a front mandrel thrust block that has a distance of at least 30 m from a feed chuck, measured with the feed clamping carriage at the rear reversal point thereof. The distance is measured between the rear (in the feed direction of the hollow) end of the chuck of the front mandrel thrust block and the front (in the feed direction of the hollow) end of the feed chuck of the feed clamping carriage at the rear reversal point thereof.