Welding and Processing Technologies for Steel Pipes
High-Frequency Longitudinal Welding Technology for Steel Pipes
The rapid transformation and development of high-frequency longitudinal welded steel pipes has become an advanced scientific technology and is increasingly refined. From the initial roll forming to the later pass roll forming, and then to flexible forming, straight-edge forming, and combinations with other rigid frames, intelligent forming has already been achieved to a certain extent. In addition to welding and power supply technologies in the steel pipe welding process, it has now evolved into a fully solid-state system starting from the pipe forming stage, significantly increasing the thermal energy output compared to the original setup.
Researchers have been dedicated to addressing existing issues in high-frequency welding technology, proposing practical solutions to improve and correct the problems. By focusing on strengthening the welding zone, they have developed new welding technologies and quality control methods, significantly reducing the risk of incomplete welds, and achieving welding performance that is very close to the base material. This improves overall product performance and quality, and it is widely used in critical applications such as oil well pipes.
Welding Technology for Titanium Alloys and Steel Pipes
The welding process between titanium alloys and steel mainly depends on the differences between the two materials and their metallurgical compatibility. The main technical challenge in welding titanium alloys with steel pipes lies in their vastly different linear expansion behaviors during the welding cooling process, leading to deformation mismatches.
In addition, the low mutual solubility between titanium and steel results in the formation of hard and brittle intermetallic compounds during welding, typically titanium-ferrite compounds. These are mainly caused by the diffusion between titanium and iron during the welding process, and the oversaturation of iron in titanium continues for a period of time, producing titanium ferrite.
Welding Reinforcement for Corrosion Pits in Steel Pipes
During the transportation of petroleum, natural gas, and other materials, corrosion media, soil pH, and moisture in the surrounding environment often cause wall thinning in steel pipes, reducing the strength and thickness below acceptable limits. Additionally, mechanical damage due to displacement and human interference can cause local damage to the soil layers, leading to poor pipeline operation and significant losses. Therefore, in online welding maintenance operations, sleeve maintenance welding and pressure drilling installation are commonly used techniques.
