... 2011. (Formerly known as YingKou OuYang Steel Tube Co., Ltd.)YingKou OuYang Metal Manufacturing Co., Ltd. is one leading manufacturer in the oil field ... the process of oil casing, tubing, casing coupling, pup joint, reducer union, drill pipe coupling and also can process the ... we have established a stable supply relationships with them. For overseas market, our products are exported to South East, M.E ...