I plant the drill pipe joints, high hardness, wear resistance, and ... China has the largest production line of drill pipe and fittings, equipment, including large flat 1250T ... machine, a group of specialized inspection tools. Drill pipe into filaments buckle and friction welding, and overall ... has DZ40, DZ50, R780, G105, S135 Series. Drill pipe joints by YB235-70 processing, materials are 40Cr, 35CrMo, ...