Effect Of Heat Transfer Conditions On Lateral Directional Solidification Process And Microstructure

Directional solidification is a process method for producing high-quality extra-thick slabs.Compared with traditional steel ingot production,it has significant quality advantages,and the cost is lower than that of electroslag remelting.Controlling its solidification process and organization is the key to the industrial production of this process.Aiming at the key parameters,this paper uses a combination of thermal experiments and numerical simulations to study the influence of heat transfer conditions on the lateral solidification process and microstructure.Designed a simulation device for lateral directional solidification,carried out experiments of Sn-Bi alloy,casting test of 42 Cr Mo steel,established a mathematical model of lateral directional solidification,and studied the influence of heat transfer conditions on the process and structure of lateral directional solidification.Research indicates:Under the casting test conditions,the lengths of columnar crystal formation under water cooling and air cooling were 130 mm and 90 mm,respectively,and the columnar crystals were 44.4% longer than air cooling under water cooling.And there are more substructures and internal stresses in the grains produced under water cooling conditions.The columnar crystals grown laterally in the center of the insulation under water cooling were shortened by 33.3%.The average grain size of 106.1um was 37.8% smaller than that of the air-cooled average grain size of 170.8um,which was denser.Under the conditions of this numerical simulation,as the body nucleation rate decreased from 1× 107 to 1× 105,the required columnar crystal length increased from 10.2mm to 172.0mm.The cooling intensity of 3000 W / m K is more suitable for the growth of columnar crystals,and 1100 ? is the best preheating temperature.