Square tubes are steel pipes with typical hollow square cross-sections made from steel billets or steel strips through rolling or welding. They are also known as hollow profiles or structural square tubes.

In the standard system of the American Petroleum Institute (API), API 5L usually refers to the pipeline steel standard, which mainly includes two specifications: PSL1 and PSL2.

Carbon steel welded pipes are mainly produced by bending carbon steel strips or steel plates into tubular shapes through various forming processes and then manufacturing them using different welding techniques. Their types mainly include ERW, LSAW, and SSAW.

In modern industrial and civil buildings, steel pipes remain one of the most important and widely used conveying and supporting materials. It is widely applied in fields such as building structures, fluid transportation, and mechanical manufacturing.

API 5L is the standard specification of the American Petroleum Institute for steel pipes of fluids such as oil and natural gas. It covers two types of steel pipes: seamless steel pipes and welded steel pipes, and is divided into two product specification grades: PSL1 (Basic grade) and PSL2 (Advanced grade). PSL1 is the most common and cost-effective type in the industry, suitable for general conveying applications.

Galvanized carbon steel pipes and stainless steel pipes are two key types of steel pipes widely used in the fields of construction, chemical engineering and industry.

Among numerous carbon steel pipe products, API 5L PSL 2 carbon steel pipe, as an internationally recognized high-standard product, features strict chemical composition control, excellent mechanical properties and outstanding corrosion resistance, and is widely used in pipeline engineering in the oil and gas industry.

Steel piles, as an important material for support and foundation structures, mainly include two types: pipe piles and sheet piles. Steel piles play a crucial role in bridge, construction, port, foundation pit and coastal engineering.

EFW (Electric Fusion Welded) steel pipe, also known as electric fusion welded steel pipe, is a kind of longitudinal straight seam welded pipe formed by melting and welding the edges of the steel strips on both sides by arc or resistance melting process.

In various piping projects, it is crucial to understand the difference between Schedule 40 (SCH 40) and Schedule 80 (SCH 80) piping.

Among various types of pipes, seamless pipes and seam pipes have become the two most common types due to their unique manufacturing processes and performance characteristics.

Resistance welded Pipes (ERW Pipes) have become key materials in oil and gas pipeline engineering due to their excellent mechanical properties, controllable weld quality and significant cost advantages.

LSAW and SSAW are two common manufacturing processes for welded steel pipes. LSAW stands for Straight seam Submerged arc welded steel pipe, while SSAW stands for spiral seam submerged arc welded steel pipe.

SSAW (Spiral Submerged Arc Welded) steel pipe is a kind of large-diameter and high-strength welded pipe made by rolling the steel strip at a specific spiral Angle and applying Submerged arc welding technology at the spiral seam.

LSAW steel pipe, also known as straight seam submerged arc welded steel pipe, is made by using steel plates as the base material, processing them into shape, and then performing submerged arc welding along the longitudinal direction of the steel pipe to form large-diameter and high-strength welded steel pipes.