1.OD:2 3/8"-6 5/8" 2.Grade:E,X,G,S 3.Upset:IU,EU,IEU ... thread gauges. To improve the galling-resistance during initial break-in and drilling operation, all threads are also phosphated or coppered ... on the connections. Drill pipes of our company are produced in accordance to Standards of API 5DP, API7 &7-1, NS ... ,ISO 14001, OHSAS 18001, Arnco Hardbanding Certificates and so on. 2 3/8--5 1/2 drill pipe