Abstract: Introduced here are the production capacity of the HFW pipe welding mill and the R&D situation of high grade HFW oil casing.For N8OQ, L80-1 and P110 high strength HFW oil casings developed by quenching and tempering process, a series of tests and analysis found out that their material structure, strength and toughness ect.have all changed after quenching and tempering, and their mechanical properties meet the requirements of API Spec 5CT (9th edition) and satisfy the technical requirements of customers.The analysis indicates that material composition and quenching and tempering are the key factors for realizing the production of the high grade HFW oil casing.