,ASTMA252, ASTM A53, API 5L1,5L2, API 5CT, GBT/ 9711.1 GBT/9711.2 EN10217,EN10219 ... steel pipe / line pipe2.Standard,ASTMA252, ASTM A53, API 5L1,5L2, API 5CT, GBT/ 9711.1 GBT/9711.2 EN10217,EN102193 ... steel pipe / line pipe2.Standard,ASTMA252, ASTM A53, API 5L1,5L2, API 5CT, GBT/ 9711.1 GBT/9711.2 EN10217,EN102193 ...