Insulated Conductor Cold Working and Heat Treating
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Solution Overview
Problem
The manufacture and assembly of long insulated conductors for subsurface heating applications face issues such as electrical and mechanical degradation, core bulge, and mechanical stress, leading to potential operational failures.
Innovation Solution
A method involving cold working and heat treating steps to reduce the cross-sectional area of insulated conductor heaters by at least 30% and up to 20% in a final step, with heat treatment at temperatures above 870°C, to enhance mechanical integrity and electrical reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If cold working and heat treating steps are performed to reduce cross-sectional area by at least 30%, then mechanical integrity and electrical reliability are improved, but manufacturing complexity and process time increase
Solution Approach 1:
The manufacturing process is divided into distinct stages: initial cold working to reduce cross-sectional area by at least 30%, followed by heat treating, and finally a second cold working step to achieve the final dimensions. This segmentation allows each step to be optimized independently, ensuring mechanical integrity and electrical reliability while managing overall process complexity.
Solution Approach 2:
The first cold working step performs preliminary reduction of cross-sectional area before heat treating. This preliminary action prepares the material structure for subsequent heat treatment, ensuring that the final dimensions and properties are achieved through controlled sequential operations rather than attempting single-step formation.
2Stability of the object's composition
If cold working is performed to reduce cross-sectional area by at least 30%, then core bulge and mechanical defects are reduced, but manufacturing precision requirements increase
Solution Approach 1:
The manufacturing process employs periodic alternating actions of cold working and heat treating. The first cold working step reduces cross-sectional area by at least 30% to eliminate core bulge, followed by heat treating to restore material properties, and then a second cold working step to achieve final precision dimensions. This periodic alternation allows structural stability to be improved while managing dimensional control requirements at each stage.
Solution Approach 2:
The process utilizes parameter changes through heat treating after cold working. The heat treatment step changes the material's physical parameters (temperature, microstructure) to restore ductility and reduce internal stresses caused by the 30% cross-sectional area reduction, thereby enabling subsequent precision dimensional control without compromising structural stability.
3Reliability
If heat treating is performed at temperatures above 870°C, then electrical insulator degradation is reduced, but energy consumption and manufacturing time increase
Solution Approach 1:
The heat treating step is performed at high temperatures above 870°C to rapidly achieve the desired electrical insulator properties and eliminate degradation issues. This rushing through the heat treatment process at elevated temperatures ensures complete restoration of material properties and electrical insulator reliability in a single intensive step rather than prolonged lower-temperature treatment, optimizing energy usage for the critical reliability improvement.
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 process improves the mechanical and electrical reliability of insulated conductors, reducing the likelihood of operational failures and extending their lifespan by minimizing mechanical stress and degradation during assembly and installation.
Implementation Method 1
insulated conductor heaters used to heat subsurface formations that contain hydrocarbons
Implementation Method 2
cold working and heat treating steps to reduce the cross-sectional area of insulated conductor heaters
Implementation Method 3
heat treating the insulated conductor heater at a temperature of at least about 870° C.
Data Source
AI summary
A method for forming an insulated conductor heater includes placing an insulation layer over at least part of an elongated, cylindrical inner electrical conductor, placing an elongated, cylindrical outer electrical conductor over at least part of the insulation layer to form the insulated conductor heater; and performing one or more cold working/heat treating steps on the insulated conductor heater, reducing the cross-sectional area of the insulated conductor heater by at most about 20% to a final cross-sectional area. The cold working/heat treating steps include cold working the insulated conductor heater to reduce a cross-sectional area of the insulated conductor heater; and heat treating the insulated conductor heater at a temperature of at least about 870° C. The insulation layer includes one or more blocks of insulation.