Research and Development of Slab Continuous Casting Sulfur Y55 Steel Plate and Its Properties

In order to meet manching and usability needs of mold steel, a slab continuous casting sulfur Y55 steel plate was successfully developed through adding free-cutting element sulfur, appropriate manganese and calcium, and optimizing smelting, continuous casting and rolling processes; its mechanical and cutting performances were analyzed.The results show that the hardness of Y55 steel plate was 180-200 HB, the steel's microstrucure was pearlite and reticular ferrite, and the inclusions were composite inclusion mainly MnS-oriented. Compared with S50C steel plate, the machining performance of Y55 steel plate was improved sharply.