Effect of casting speed on size and distribution of carbide in 30Cr13 continuous casting slab
30Cr13 is a high quality stainless steel for cutting tools.The development of continuous casting technology has greatly improved its production efficiency.Casting speed is an important process parameter and technical indica-tor in the continuous casting process.When the casting speed is not suitable,it is easy to form a large amount of un-evenly distributed carbides,and the size and distribution of carbides are key factors affecting the quality of continuous casting slabs.Taking 30Cr13 continuous casting slab as the research object,the morphology,size,and type of car-bides in different solidification structures in continuous casting slabs of 0.75 m/min,0.80 m/min,and 0.85 m/min were analyzed by Scanning electron microscope,Light microscopy,X-ray diffraction.The effect of casting speed on carbides in 30Cr13 continuous casting slab was studied based on the solidification microstructure morphology,and the effect law of casting speed on carbides in continuous casting slab was summarized.The results show that the main morphology of carbides is clusters,blocks,and strips,and the main components are Fe,Cr,and C.The main types of carbides have been determined to be(Fe,Cr)7C3 and(Fe,Cr)23C6.And it was found that there were no car-bides present at the"white bright band",and a large amount of carbides appeared in the sample between the"white bright bands",with the most carbides appearing at the center of the slab.The casting speed has no effect on the shape,type,and location of carbides,but has a greater impact on the quantity and size of carbides.As the casting speed increases,the proportion of total carbide area and number density first decrease and then increase.When the casting speed is 0.80 m/min,the proportion of carbide area and number density in the continuous casting slab is the lowest.This change is consistent with the trend of the degree of deviation of the C segregation index from the nor-mal value under different casting speeds.With the increase of casting speed,the proportion of small-sized carbides increases gradually,while that of large-sized carbides are almost zero.The speed of 0.80 m/min can effectively con-trol the size distribution of carbides in continuous casting slab and improve the quality of the slab.
continuous casting slabsolidified structurecasting speedcarbidessize and distribution
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