... 2m)No.Steel typeSteel gradeannual output/t1Oil casing Pipe, joint material J55,K55,N80-11000002Oil line pipeB,X42~X60( ... seamless steel tubes10#~45#,40Mn2,35Cr,35CrMo500007Hydraulic pillar tube, cylinder sleeve etc.45#,27SiMn20008pipes for high-pressure fertilizer equipment20G, ... gradeAnnual output/t1Oil casing Pipe, joint material J55,N80,L80,C90,P110850002Oil casing Pipe, joint material J55,N80,L80-1, ...