casing pipe: Clean and pure steel quality, well- proportioned and stable ingredients, perfect furface quality, high precision casing pipe:Tubing is used to extracting petroleum and natural gas from a well.Summury products as follows: Standard specificationStandard No.Normal Steel GradeCasing and TubingAPI 5CTJ55, N80, P110, L80, C90, T95Line pipeAPI 5LA, B, X42, X46, X52, X5, X60Drill pipeAPI 5DE ...