Effects of continuous casting process parameters on carbon segregation degree of 38CrMoAl steel big round billet

The effects of continuous casting process parameters (superheat degree, casting speed and F- EMS) on the carbon segregation of round billet with diameter 600mm of 38CrMoAl steel were investigated by industrial experiments and numerical simulations. The results show that the equiaxed crystal rate and solidification structure both affect the carbon segregation. When the superheat is low, shrinkage tends to occur, and the shrinkage is often accompanied by severe segregation. When the superheat is high, the equiaxed grain ratio is lower, carbon segregation is also severer, so the superheat degree is controlled at 30??. With the increasing of casting speed?? it can obviously spur the growth of columnar crystals and formation of central pipe; both columnar crystals and central pipe are the major cause of segregation, so the suitable casting speed is 0. 19m/min. Final electromagnetic stirring has the effect of uniform liquid steel composition and temperature, which increases the density of solidification structure, and reduces the central shrinkage hole, thereby reducing carbon segregation, but the electromagnetic stirring effect is greatly affected by the installation position. Based on comprehensive consideration of the production and quality in practical production, the suitable process parameters are established: the optimal superheat is 30??, casting speed is 0. 28m/min, the combination of electromagnetic stirring is M- EMS+S- EMS+F- EMS, and the corresponding electromagnetic stirring parameters are M- EMS of 101A/2Hz??S- EMS of 200A/8Hz??F- ME of 900A/8Hz. Under the above process conditions, it will be more reasonable for the F- EMS installation position to move 0. 4-0. 5m toward the meniscus.