Size Range Outside Diameter: 219.1-508mm Wall Thickness: 8.18-12.7mm Applications: The pipes are used for transportation of petroleum, natrual gas and mineral slurry, also for mining, mechanism, construction, truss structure, agriculture irrigation, chemical industry, electric power engineering, etc...The pipes can replace the seamless pipes in some fields. The welded steel pipes in Dia. 21.3-323.9mm: The products are used for the repair of pipeline for all oil and gas fields and the transportation of oil and natural gas. The welded steel pipes in dia. 219.1-508mm follow strictly the standard of API 5L specification.