... ) of 2-3/8",2-7/8",3-1/2,4",4-1/2",5",5-1/2"oil drilling pipe :-Drilling ... , We are equipped with facilities of top quality in the world, such as hydraulic upset forging machine, ... . To improve the galling-resistance during initial break-in and drilling operation, all threads are also phosphated ... of our company are produced in accordance to Standards of API 5DP, API7 &7-1, NS-1. RUSSIA RTN, RUSSIA GOST ...