Seamless Tube Rolling Plant Mandrel Segmentation
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Solution Overview
Problem
Current seamless tube rolling processes face challenges in effectively controlling the outer diameter and wall thickness, requiring significant mandrel stock, high running costs, and complex machinery, which leads to inefficiencies and large tolerances.
Innovation Solution
A continuous rolling plant with a main rolling mill using a slow, composite mandrel and an extracting/reducing mill with adjustable rolls, along with a sizing mill having radially adjustable rolls, allows for real-time control of tube parameters, reducing mandrel length and stock, and optimizing tube finishing with smaller tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a retained mandrel is used in the main rolling mill, then the mandrel can contrast the radial thrust during rolling, but the mandrel temperature increases significantly due to passage through multiple rolling stations
Solution Approach 1:
The mandrel is divided into multiple separable sections (first mandrel section, second mandrel section, etc.) that can be independently managed. This segmentation allows each section to be cooled and lubricated separately after passing through rolling stations, preventing the cumulative temperature increase that would occur with a single retained mandrel.
Solution Approach 2:
The mandrel sections are designed to be nested or coupled together during rolling operations, forming a complete mandrel structure that spans multiple rolling stations. The sections can be coupled in sequence as they pass through the rolling mill, allowing the mandrel to maintain its contrast function while enabling thermal management of individual sections.
2Temperature
If multiple mandrels are used to ensure operation of the main rolling mill, then mandrel temperature control is improved, but the outlay for mandrel stock increases considerably
Solution Approach 1:
By segmenting the mandrel into reusable sections, the system reduces the total number of complete mandrels needed. Each section can be detached, cooled, lubricated, and reused in subsequent rolling operations, thereby reducing mandrel stock requirements while maintaining temperature control.
Solution Approach 2:
The mandrel sections are designed to be temporarily discarded (detached) after serving their function in a rolling operation, then recovered (reused) in subsequent operations. This allows the same physical sections to serve multiple rolling cycles, reducing the need for large mandrel stock while maintaining operational continuity.
3Device complexity
If the radial position of rolls is not adjustable in the sizing mill, then the mill structure is simpler, but the control over tube diameter precision is insufficient
Solution Approach 1:
The sizing mill incorporates radially adjustable rolls that can dynamically change their position during operation. This allows the roll gap to be precisely controlled to achieve the desired tube outer diameter while maintaining a relatively simple overall mill structure. The adjustability is achieved through mechanisms that allow radial movement of rolls while keeping the basic mill framework compact.
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 solution enables more precise control over tube dimensions, reduces operational costs, and simplifies logistics by minimizing mandrel requirements and temperature variations, achieving better diameter and thickness tolerances compared to traditional methods.
Implementation Method 1
produce seamless metal tubes by means of successive plastic deformation of a starting billet
Implementation Method 2
the mandrel is subject to high thermal and mechanical stresses due to the deformation energy and the friction produced by the sliding contact of the tube material
Data Source
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AI summary
The present invention relates to a plant for rolling a seamless tube, typically with a medium-to-large diameter. The plant comprises a main rolling mill with adjustable rolls for mandrel-rolling a semifinished tube. The plant also comprises a fixed-roll extracting/reducing mill positioned downstream of the main rolling mill and in series therewith. The extracting/reducing mill is designed to extract the semifinished tube from the mandrel and reduce its diameter to a predetermined value close to that desired for the finished tube. Finally, the plant comprises a adjustable-roll sizing mill. The sizing mill is positioned downstream of the extracting/reducing mill and off-line with respect to the latter. This sizing mill is designed to adjust the radial position of the rolls and define the diameter of the outgoing tube. The invention also relates to a method for rolling a seamless tube.