1. What standards are ERW steel pipes produced in accordance with?
ERW steel pipes are produced in accordance with international and national standards, including: API 5L (American Petroleum Institute standard, for oil and gas transportation steel pipes); GB/T 3091-2015 (Chinese national standard, for low-pressure fluid输送用焊接钢管); GB/T 9711-2017 (Chinese national standard, for oil and gas transportation steel pipes); ASTM A53 (American Society for Testing and Materials standard, for black and hot-dipped galvanized welded and seamless steel pipes for pressure and non-pressure applications); DIN 2440 (German standard, for welded steel pipes for general purposes); and EN 10217 (European standard, for welded steel pipes for pressure purposes).
2. What is the difference between ERW and HFW steel pipes?
HFW stands for High-Frequency Welding, which is a type of ERW (Electric Resistance Welding). In other words, HFW is a specific form of ERW. The main difference is that HFW uses high-frequency current (usually above 100kHz) to heat the steel strip edges, which has the advantages of fast heating speed, uniform temperature, and high weld quality; while traditional ERW may use low-frequency or medium-frequency current, which is suitable for small-diameter and thin-walled pipes. At present, most ERW steel pipes produced in the industry are HFW steel pipes, which are widely used in various fields.
3. Can ERW steel pipes be cut and processed according to customer requirements?
Yes, we can cut and process ERW steel pipes according to customer requirements. Common processing methods include: cutting (cutting the pipe into the required length, such as 3 meters, 5 meters, etc., using plasma cutting, flame cutting, or sawing); beveling (processing the pipe end into a bevel to facilitate welding connection); threading (processing internal or external threads on the pipe end for threaded connection); and punching (drilling holes on the pipe body according to the installation needs). All processing operations are carried out in strict accordance with customer drawings and standards to ensure the accuracy and quality of the processed products.
4. What is the weight per meter of ERW steel pipes?
The weight per meter of ERW steel pipes can be calculated using the formula: Weight (kg/m) = 0.02466 × (Outer Diameter - Wall Thickness) × Wall Thickness. For example, an ERW pipe with an outer diameter of 108mm and a wall thickness of 4mm has a weight per meter of 0.02466 × (108 - 4) × 4 ≈ 10.26 kg/m. The actual weight may vary slightly due to factors such as the actual wall thickness tolerance of the pipe and the material density. We can provide a detailed weight list according to the specific specifications required by the customer.
5. Are ERW steel pipes suitable for high-temperature environments?
ERW steel pipes can be used in high-temperature environments, but the maximum service temperature is limited by the material grade. Generally, low-carbon steel ERW pipes (such as Q235, A36) can be used in environments with a maximum temperature of 200-300℃; low-alloy steel ERW pipes (such as Q355, ST52) can be used in environments with a maximum temperature of 300-450℃. If the service temperature exceeds 450℃, high-temperature resistant steel materials (such as alloy steel) or seamless steel pipes are recommended, because high temperature will reduce the mechanical strength and weld stability of ERW pipes.
