... .2m) No.Steel typeSteel gradeannual output/t1Oil casing Pipe, joint materialJ55,K55,N80-11000002Oil line pipeB,X42~ ... typeSteel gradeAnnual output/t1Oil casing Pipe, joint materialJ55,N80,L80,C90,P110850002Oil casing Pipe, joint materialJ55,N80,L80-1 ... Q345350005high-pressure boiler tube20G,20MnG,25MnG,12Cr1MoVG,15CrMoG,P9145006lower/medium-pressure boiler tube10,20200007Hydraulic pillar tube20,30,45, ...