Coiled Tubing Tempering to Prevent Cracking During Bending
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Solution Overview
Problem
Existing heat treatment methods for coiled tubes often result in significant deformation and defects due to the brittleness of the material, leading to cracking and breakage during coiling or uncoiling, posing safety hazards and affecting the tube's performance under fatigue loads.
Innovation Solution
A method involving a two-stage tempering process where the coiled tube is initially tempered in a straight or uncoiled state to achieve a minimum ductility, followed by optional further tempering after coiling, to minimize deformation and defects during heat treatment, allowing for bending without cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If coiled tubing is bent several times inside a furnace for heat treatment, then the required residence time in the furnace is achieved, but significant defects and cracking occur in the coiled tube
Solution Approach 1:
The patent applies preliminary tempering to the coiled tube before it enters the furnace for heat treatment. This pre-tempering process reduces the brittleness of the as-quenched material in advance, allowing the tube to withstand the bending required for furnace processing without developing cracks or defects, thus achieving both adequate residence time and defect-free reliability
Solution Approach 2:
The patent applies preliminary tempering to counteract the brittleness of the as-quenched material before the harmful bending action occurs. By reducing brittleness in advance, the material becomes resistant to the cracking that would otherwise result from the necessary furnace bending operations
2Loss of time
If coiled tubing is bent inside the heated chamber to achieve minimum residence time, then the heat treatment duration is sufficient, but the tube suffers deformation and cracking
Solution Approach 1:
The patent applies preliminary tempering before the tube enters the heated chamber, which reduces brittleness in advance and enables the tube to undergo necessary bending deformations during heat treatment without suffering excessive deformation or cracking, thus maintaining manufacturing precision while achieving adequate heat treatment duration
3Strength
If coiled tube is in as-quenched state during coiling, then the tube has high strength, but the material is too brittle causing cracking and breakage
Solution Approach 1:
The patent applies preliminary tempering to the as-quenched coiled tube before coiling operations. This pre-tempering reduces the brittleness of the high-strength material in advance, allowing the tube to maintain its strength while becoming ductile enough to withstand coiling and uncoiling operations without cracking or breakage
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
The method effectively reduces the risk of cracking and deformation during coiling, enhancing the tube's ductility and toughness, thereby improving its performance and safety by ensuring a defect-free product with reduced coiling strain.
Implementation Method 1
a first tempering stage, and a second tempering stage wherein the pipe is tempered within a furnace while being bent
Implementation Method 2
the coiled tube is initially tempered in a straight or uncoiled state to achieve a minimum ductility, followed by optional further tempering after coiling
Data Source
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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.