1. What does ERW stand for in ERW steel pipes?
ERW stands for Electric Resistance Welding. It is a common welding method used in the production of steel pipes, where an electric current is passed through the edges of the steel strip to generate heat through electrical resistance, and then the edges are pressed together to form a seamless joint without the need for additional welding filler materials.
2. How is an ERW steel pipe manufactured?
The manufacturing process of ERW steel pipes mainly includes the following steps: first, the hot-rolled or cold-rolled steel strip is uncoiled and leveled to ensure the flatness of the strip; then, the strip is formed into a cylindrical shape through a series of forming rollers; next, the edges of the cylindrical strip are heated by high-frequency electric resistance to reach the welding temperature (usually 1200-1350℃); finally, the heated edges are pressed tightly by welding rollers to form a firm weld, and then the pipe is sized, cut, and subjected to quality inspection to form the final ERW steel pipe.
3. What are the main raw materials used for producing ERW steel pipes?
The main raw material for ERW steel pipes is low-carbon steel or low-alloy steel strips, such as Q235, Q355 (in Chinese standard), A36, A53 (in American standard), and ST37, ST52 (in European standard). The choice of raw materials depends on the application scenario of the pipe, such as pressure-bearing capacity, corrosion resistance, and mechanical properties requirements.
4.What is the difference between ERW steel pipes and seamless steel pipes?
The core difference between ERW steel pipes and seamless steel pipes lies in the manufacturing process and structure: ERW pipes are made by welding steel strips, with a visible weld seam along the length of the pipe; seamless pipes are made by piercing a solid steel billet, without any weld seams. In terms of performance, seamless pipes have better pressure-bearing capacity and toughness, suitable for high-pressure and high-temperature environments; ERW pipes have the advantages of low production cost, high production efficiency, and uniform specifications, suitable for general low-pressure and normal-temperature applications.
5. What are the common specifications of ERW steel pipes?
The specifications of ERW steel pipes are usually expressed by outer diameter (OD), wall thickness (WT), and length. Common outer diameters range from 1/2 inch (12.7mm) to 24 inches (609.6mm), wall thickness ranges from 0.8mm to 16mm, and length is usually 6 meters, 9 meters, or 12 meters (customizable according to customer requirements). In addition, the pipe can be divided into seamless (SMLS) and welded (ERW) according to the structure, and into SCH 10, SCH 20, SCH 40, SCH 80, etc., according to the pressure grade.
