... 3/8-5 inch API 5DP Drill Pipe/Oilfield Drilling Tools: Grade:DZ50,G105,S135,R780 OD:42-127mm Length:R1 ... 3/8-5 inch API 5DP Drill Pipe/Oilfield Drilling Tools :Grade: DZ50,R780,E75,X95,G105,S135Material:40Cr,45Mn2,35CrMo ... manufacturer of drill pipes in China and has its own plant.2. Longway has advance production lines, adopts to American equipment ...