Elimination of Pearlite-Ferrite Band Using Soft Reduction During Continuous Casting of Api 5l X 65 Steel
Proceedings Publication Date
Line pipe steels are used to transport the crude oil and natural gas for the long range distances. The line pipe steel grades API X 60, API X 70 and API 80 defined by the American Petroleum Association are widely used by the line pipe manufacturers. The mechanical properties of the API grade steels are mostly affected by the segregation of alloying elements. Centre macro segregation is one of the most significant defects in continuous casting. This type of segregation causes the band structures through the steel coils. Therefore, if the cracks were occurred along these band structures, the cracks could easily move to the end of the line pipe following the band path. The most significant and effective method to reduce the macro segregation is the soft reduction which is the state-of-art of the continuous casting technology. The main aim of the soft reduction is to disperse the segregation of alloying elements using mechanical loading before the metallurgical length ends. By this way, the band structures caused by the macro segregation can be fully eliminated or reduced to negligible sizes. In this project, the soft reduction parameters are tried to find out the optimum parameters to eliminate the pearlite band for API X 65 5L PSL 2 steel grade. The micro structures of steel coils produced applied soft reduction are investigated and the band thicknesses of the coils are measured. In this research; the effect of soft reduction on the mechanical properties of final product is investigated.