Rolling Plant Orientation and Control for Pipe Integrity
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Solution Overview
Problem
Existing rolling plants face issues with irregular zones and defects in the tail of pierced blanks, leading to mechanical integrity concerns and increased risk of fragment detachment, as well as premature wear of the mandrel due to severe thermal and mechanical stress, particularly in the tapering method used to correct wall thickness.
Innovation Solution
The rolling plant and method involve orienting the pierced blank such that the regular head faces the mandrel for insertion, reducing the risk of fragment entrapment and stress, and using a control circuit to adjust the radial position of rolls based on measured distances and pressure peaks to maintain consistent wall thickness without tapering, thereby minimizing waste and mandrel wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the mandrel is inserted into the tail of the pierced blank, then the rolling process can proceed, but fragment detachment and mandrel wear occur due to irregular zones and defects
Solution Approach 1:
The patent inverts the conventional insertion direction by introducing the mandrel through the regular head instead of the irregular tail. This reversal eliminates the problem of fragment entrapment and detachment that occurs when inserting through the defective tail region, while maintaining continuous rolling productivity.
Solution Approach 2:
The pierced blank is pre-oriented during piercing so that the head with regular geometry is positioned at the end that will receive the mandrel. This preliminary positioning ensures that subsequent mandrel insertion occurs through a defect-free region, preventing mechanical integrity issues throughout the rolling process.
2Manufacturing precision
If the radial position of rolls is adjusted to correct wall thickness, then thickness uniformity improves, but mandrel wear increases due to severe thermal and mechanical stress
Solution Approach 1:
The patent applies different radial positions for rolls at different locations along the pipe length. Specifically, rolls contacting the head and tail sections are positioned differently from those contacting the central section, allowing thickness correction without concentrating excessive stress on the mandrel at any single location.
Solution Approach 2:
The patent changes the operational parameters of the rolling rolls, specifically their radial positions, to optimize both wall thickness uniformity and mandrel stress distribution. By carefully selecting roll positions, the process achieves precise thickness control while minimizing thermal and mechanical stress on the mandrel.
3Manufacturing precision
If tapering method is used to correct wall thickness, then thickness uniformity improves, but waste increases due to cutting of irregular zones
Solution Approach 1:
The patent changes the roll radial positions during the rolling process to directly correct wall thickness variations without creating tapered ends. By adjusting rolls to apply appropriate pressure at different stages, the method achieves uniform thickness throughout the pipe length, eliminating the need to cut away tapered sections and reducing material waste.
Data Source
AI summary
The invention relates to a pipe rolling plant 10 comprising a rotary piercer 20, a treatment station 30 and a main rolling mill 40. The rotary piercer and the treatment station are arranged so that the pierced blank 51 leaving them is arranged with the irregular tail 511 facing the main rolling mill 40 and with the regular head 510 facing the mandrel 41. The invention also relates to a rolling mill 40 comprising a plurality of rolling stations 43, each station comprising a plurality of rolling rolls 42, the radial position h of which is adjustable. The rolling mill also comprises a control circuit for calculating and/or measuring the distance d between the axes of rotation r of the rolls and the trailing edge 520 of the pipe 52. The control circuit is also designed to displace the rolling rolls radially towards the outside of the pipe in each rolling station 43n when the distance d assumes a predetermined value d0.