Straight Tempering of Coiled Tubing to Prevent Cracking
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Solution Overview
Problem
Existing methods for heat treating coiled tubing often result in significant deformation and cracking due to the need for bending the tubing during the tempering process, which can lead to defects and safety hazards.
Innovation Solution
A method of heat treating coiled tubing by tempering the unspooled pipe before any bending, allowing for minimal deformation and reducing the risk of cracking, which includes uncoiling the tubing, heating it above Ac3, quenching, and tempering it in a straight configuration, followed by optional further tempering after coiling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If coiled tubing is bent several times inside the heated chamber for tempering to achieve minimum residence times, then the heat treatment process is completed, but significant defects and cracking are caused in the coiled tube
Solution Approach 1:
The patent applies preliminary tempering action by heating and tempering the tube in a straight configuration before any bending operations. This preliminary heat treatment reduces the tube's brittleness and increases ductility, allowing subsequent bending to be performed safely without causing cracks or defects. The tempering is conducted while the tube is still in its straight, uncoiled state, which is the most favorable condition for heat treatment.
Solution Approach 2:
The patent inverts the conventional sequence by performing heat treatment first and bending second, rather than bending first and heat treating later. This reversal of the traditional process sequence eliminates the problem of cracking during tempering, as the tube is softened and made ductile before the bending operation is applied.
2Manufacturing precision
If coiled tubing is heat treated in a conventional furnace requiring bending, then tempering is achieved, but large heating chambers and complex equipment are required
Solution Approach 1:
The patent extracts the heat treatment process from the conventional large furnace environment and performs it directly on the tube in a simplified heating setup. By removing the requirement for a large heating chamber and multiple bending operations, the process is simplified to a direct tempering operation on the straight tube, reducing equipment complexity while maintaining tempering quality.
Solution Approach 2:
The patent replaces the mechanical bending system with a thermal treatment approach. Instead of using mechanical force to shape the tube and then heat treating it, the process uses thermal energy to modify the tube's properties first, making it suitable for subsequent bending without requiring complex mechanical intervention during the heat treatment phase.
3Manufacturing precision
If coiled tubing is bent during tempering to fit in heating chambers, then heat treatment is completed, but significant time is lost due to repeated bending and positioning
Solution Approach 1:
The patent performs the heat treatment action preliminarily while the tube is in its straight configuration, eliminating the need for repeated bending and positioning operations. The tempering is completed in a single continuous operation on the uncoiled tube, significantly reducing the total processing time compared to conventional methods that require multiple bending cycles to fit the tube into heating chambers.
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 approach produces defect-free coiled tubing with improved ductility and toughness, reducing the risk of cracking and enabling safe handling and coiling without the need for large heating chambers, thus enhancing industrial feasibility.
Implementation Method 1
heating it above Ac3
Implementation Method 2
quenching
Implementation Method 3
tempering
Data Source
AI summary
Embodiments of a method of heat treating a coiled tube, in particular coiled tubes for use in the oil and gas industry, and pipes produced from the methods. In particular, embodiments of the heat treating method can utilized tempering without bending in order to avoid the generation of subsequent defects.