The manufacturing technology for casing and tubing cores involves intricate processes designed to ensure superior mechanical properties and corrosion resistance, essential for their use in harsh environments. This document outlines the key technologies and methods employed in the production of high-performance casing and tubing cores, emphasizing the importance of chemical composition, processing techniques, heat treatment, welding methods, and innovative manufacturing technologies. Read on to learn more.
Chemical Composition
To withstand harsh environmental conditions, coiled tubing requires superior mechanical properties and corrosion resistance. This necessitates the optimization of the material's chemical composition and stringent control of the entire smelting and rolling process to minimize inclusions and harmful elements like sulfur (S) and phosphorus (P).
Processing
The strengthening and hardening of the tubular body are influenced by dislocation multiplication and the Bauschinger effect. Therefore, controlling these factors is essential to regulate the transformation law of tubular body strength.
Heat Treatment
Optimal control of microstructure and properties, particularly high strength, high ductility, and low residual stress, is achieved through heat treatment of the tubes.
Welding Technology
For low carbon and low alloy steels, High-Frequency Welding (HFW) technology is primarily used. Research is focused on determining optimal welding parameters (such as current, voltage, frequency, welding speed, forming angle, and pressing amount) and developing post-weld heat treatment techniques.
Butt Welding
Continuous production of HFW pipes requires the joining of long sheets. Current methods primarily use Tungsten Inert Gas (TIG), Metal Active Gas (MAG), and plasma welding. Friction Stir Welding (FSW) is being explored as an alternative method.
Pipe Butt Welding
During the use of coiled tubing, local damage or defects may necessitate the removal and rejoining of pipe sections through welding. Traditional manual TIG welding poses challenges in quality control, prompting a shift towards automatic welding technologies.
New Manufacturing Technologies
Continuous Variable Rolling (CVR) technology employs continuous pipes of the same size, heated to 940°C via online medium frequency induction. This method aims to optimize seamless or HFW welds and allows for adjustable wall thickness. Additionally, continuous laser welding technology is being developed for special stainless steel tubes.
