Key technologies for high grade pipeline refining

Key technologies for the control of sulphur, phosphorus, nitrogen, oxygen, hydrogen, inclusions, slab quality, and narrow composition refining are assembled on studies by systematic sampling, process, and technologies analyzing about high grade pipeline production in various Chinese steel groups. Systematical process optimization of hot metal pretreatment, converter refining, secondary refining and continuous casting, and the assemble of special controlling technologies for various components against their characterizations and requirements are two important aspects of impurity and inclusion controlling for high grade pipeline steel. The application of the new inclusion modification standard on calcium treatment, and the improvement of process and technologies for unsteady casting are keys for the control of inclusions' harm on pipeline properties. While, the coordination of the optimized continuous casting process, perfect equipment management, and the appropriate refining process are keys for no defect slab production.