Grading evaluation of non-API OCTG quality level based on working conditions

The non-API standard series of oil country tubular goods (OCTG) have been developed rapidly to meet the increasing demand and gas fields, while frequent accidents OCTG still occur due lack a perfect quality management system. In this paper, main types, service conditions, current status evaluation technology at home abroad were introduced. For problems during domestic application, needs industry development continuous improvement system taken into consideration. Based on working quantitative method grading was built by idea represented capability maturity model integration (CMMI) based field conditions. And an method, including process level, items, indexes procedures, proposed verified. results showed that average value level 81.5 C, respectively, which in good accordance with product management. is more targeted, would provide for completeness methodological support theoretical reference.