... 11-16 1. Execute standard:API 5L Specification for Line Pipe ,API SPEC 5CT, Specification for Casing and TubeGB/T3087 ... Low and middle pressure fluid transportation pipeline,Casing Tube, Boiler Pipe,Petroleum and natural gas industry,Chemistry industry,Electric industry, ... Drainage project,City construction,Low and middle pressure boiler pipeline , etc .3. Material:Q235-Q345, A25-X70 ...