Control of Cr-bearing carbides in 30Cr13 continuous casting slabs through roller electromagnetic stirring at the second cooling zone

30Cr13 martensitic stainless steel contained a significant amount of carbon and alloy elements. During the continuous casting process, a considerable number of uneven carbides were prone to form, affecting the quality of the continuous-cast slabs. An analysis was conducted on the total area, number density, and size variations of carbides at different locations of 30Cr13 slabs under varying electromagnetic stirring currents and frequencies of the rollers. The results indicated that the proportion of carbides was highest in the central region, with the highest proportion of large-sized carbides. As the electromagnetic stirring current increased, the proportion of carbide area decreased, the proportion of small-sized carbides increased, and the proportion of large-sized carbides decreased. With an increase in stirring frequency, the area and size of carbides followed the same pattern. When the electromagnetic stirring parameters were set at 300 A and 8 Hz, the total area of carbides in the 30Cr13 slab was lower, and the proportion of small-sized carbides was higher. An increase in stirring current or frequency reduced the degree of carbon segregation, thereby decreasing the proportion of carbide area and the proportion of large-sized carbides.