What is stainless steel welded pipe?

Stainless steel welded pipe, abbreviated as welded pipe, is a steel pipe commonly made by welding steel or steel strip after being rolled and formed by a machine and a mold. The production process of welded steel pipes is simple, with high production efficiency, multiple varieties and specifications, and less equipment investment, but generally lower strength than seamless steel pipes.

Since the 1930s, with the rapid development of high-quality strip steel continuous rolling production and the advancement of welding and inspection technology, the quality of welds has been continuously improved, and the variety and specifications of welded steel pipes have been increasing. They have replaced seamless steel pipes in more and more fields, especially in heat exchange equipment pipes, decorative pipes, medium and low pressure fluid pipes, etc.

What is stainless steel seamless pipe?

Stainless steel seamless pipe is a long strip of steel with a hollow cross-section and no seams around it. The thicker the wall thickness of the product, the more economical and practical it is. The thinner the wall thickness, the higher its processing cost will be.

The process of this product determines its limited performance. Generally, seamless steel pipes have low accuracy, such as uneven wall thickness, low surface brightness inside and outside the pipe, high sizing cost, and difficult to remove pitting and black spots on the inner and outer surfaces; Its detection and shaping must be processed offline. Therefore, it demonstrates its superiority in high pressure, high strength, and mechanical structural materials.

What is duplex stainless steel pipe?

Dual phase stainless steel pipes have good welding performance. Compared with ferritic stainless steel and austenitic stainless steel, they are not like the welding heat affected zone of ferritic stainless steel. Due to severe grain coarsening, their plasticity and toughness are greatly reduced, and they are not as sensitive to welding hot cracks as austenitic stainless steel.

Due to its special advantages, duplex stainless steel is widely used in industrial fields such as petrochemical equipment, seawater and wastewater treatment equipment, oil and gas pipelines, papermaking machinery, etc. In recent years, it has also been studied and used in the field of bridge load-bearing structures, with good development prospects.

Dual phase stainless steel has half of the ferrite phase and half of the austenite phase in its solid quenching structure, and the minimum phase content may generally reach 30%.