... :GB/T3091-2008,GB/T9711.1, API5L etc.2) Sizes:a)OD:325mm-1220mm b)Wall Thickness:8mm-80mm c)Length:6m ... .4) Application:Structural pipe,liquid transportation,conveyance of oil and gas,petroleum transportation etc.5) Marking:the sizes,steel grade or ... .4) Application:Structural pipe,liquid transportation,conveyance of oil and gas,petroleum transportation etc.5) Marking:the sizes,steel grade or ...