1. The approval procedure for batch acceptance of straight seam steel pipes shall comply with the corresponding product standards.
2. Straight seam steel pipes shall comply with the corresponding product standards, including inspection items, sampling quantity, sampling location and test methods. With the consent of the buyer, hot-rolled seamless steel pipes may be sampled in batches according to the number of rolled roots.
3. If there are items that do not meet the requirements of the product standards, the unqualified items should be selected, and double samples should be taken from the same batch of straight seam steel pipes to recheck the unqualified products. If the re-inspection results do not meet the standards, the batch of straight seam steel pipes shall not be shipped.
4. Straight seam steel pipes that do not meet the standards (including items whose organization does not meet the standards and are not allowed to be re-inspected) shall be submitted to the supplier for acceptance at one time, or a new batch of reheat treatment shall be accepted (reheat treatment should not exceed twice).
5. If there are no special provisions in the product standard, the chemical composition of the straight seam steel pipe will be accepted according to the melting composition.
What is the difference between straight seam steel pipes and high-frequency straight seam steel pipes?
A welded steel pipe with only one longitudinal weld is a straight welded steel pipe. According to the provisions of GB/9711.1, the diameter of the straight welded steel pipe is greater than 914.4, the welding angle is 180°, and there can be two straight seam steel pipes that are the same.
Straight seam steel pipes can be divided into JCOE straight seam steel pipes and rolled straight seam steel pipes according to the production process.
High-frequency straight seams, submerged arc straight seams, electric welded straight seams, pipe straight seams, etc. are collectively referred to as straight seam steel pipes. High-frequency straight seam steel pipes use the high-frequency current skinning effect to produce high-temperature external short-time force extrusion at both ends of the steel plate. It is a real electrodeless metal butt joint. With hot-rolled coils as raw materials, the wall thickness of ERW high-frequency straight seam steel pipes can be controlled at about ±0. The 2mm steel pipe end meets the US APL standard or GB/T 9711.1 standard. The pipe end is cut and the transportation length is fixed. In recent years, ERW steel pipes have been widely used as the main steel pipes for natural gas pipeline projects and urban pipelines of gas companies. At present, high-frequency straight seam steel pipes left over from the war account for 60% of the world's steel pipes.
Double-sided submerged arc straight seam steel pipes are also straight seam steel pipes. Submerged arc welding straight seam steel pipes adopt JCOE cold forming process, welding wire is used for the weld, and granular flux is used for submerged arc. The main production process of submerged arc welding straight seam steel pipes is flexible and can produce any specifications, with a wall thickness of 325~1420 mm. It largely meets the international requirements for steel pipe sizes, while high-frequency straight seam steel pipes are usually used in domestic standard production.
High-frequency straight seam steel pipes are often called original steel pipes. The name of the industry is different from submerged arc welding straight seam steel pipes or thermal expansion high-frequency straight seam steel pipes, and their names are often confused.
The above content is to share with you what is a straight seam steel pipe. I hope that reading this article can help you. Thank you for your reading. Please continue to pay attention. See you next time.
