Effect of low-frequency rotary electromagnetic-field on solidification structure of continuous casting austenitic stainless steel

Abstract

To understand the solidification behavior of austenitic stainless steel in rotary electromagnetic-field, the influence of low-frequency rotary electromagnetic-field on solidification structure of austenitic stainless steel in horizontal continuous casting was investigated based on industrial experiments. The results show that the solidification structure of austenitic stainless steel can be remarkably refined, the central porosity and shrinkage cavity can be remarkably decreased, and the equiaxed grains zone are enlarged by means of application of appropriate low-frequency electromagnetic-field parameters. The industrial trials verify that the stirring intensity of austenitic stainless steel should be higher compared with that of plain carbon steel. Electromagnetic stirring affects the macrostructure even if the average magnetic flux density of the electromagnetic stirring reaches 90 mT (amplitude reaches 141 mT) with the frequency of 3–4 Hz. Due to a higher viscosity, rotating speed of molten stainless steel is 20%–30% lower than that of molten carbon steel in the same magnetic flux density.

Keywords

horizontal continuous casting / austenitic stainless steel / electromagnetic stirring / equiaxed grains / central porosity

References

[1] HaissigM.. Horizontal continuous casting: A technology for the future [J]. Iron Steel Eng, 1984, 61(6): 65-71

[2] BiratJ. P., ChoneJ.. Electromagnetic stirring on billet, bloom and slab continuous casters: State of the art in 1982 [J]. Ironmaking and Steelmaking, 1983, 10(6): 401-408

[3] LiuS.-f., KangL.-g., HanH., LiuL.-y., ZouX.-q., GuoH.-he.. Influence of electromagnetic stirring on microstructure of AZ91-0.8%Ce magnesium alloy [J]. J Cent South Univ Technol, 2006, 13(6): 613-617

[4] YangJ., DangJ.-z., PengY.-g., ChengJ.. Design method of electromagnetic field applied to Al-alloy electromagnetic casting [J]. Trans Nonferrous Met Soc China, 2006, 16: s1437-s1441

[5] TakehikoT., EiichiT., MasatakeH., HiroyukiK., ShogoM.. Electromagnetic control of initial solidification in continuous casting of steel by low frequency alternating magnetic field [J]. ISIJ International, 1997, 37(11): 1112-1119

[6] ChoY. W., OhY. J., ChungS. H., ShimJ. D.. Mechanism of surface quality improvement in continuous cast slab with rectangular cold crucible mold [J]. ISIJ International, 1998, 38(7): 723-729

[7] KolesinchenkoA. F., KolesichenkoA. A., BuryakV. V.. Improvement of in mold electromagnetic stirrer by feeding of magnetic system with polyharmonic current [J]. ISIJ International, 2004, 44(2): 342-349

[8] KurzW., BezenconC., GäumannM.. Columnar to equiaxed transition in solidification processing [J]. Science and Technology of Advanced Materials, 2001, 2(1): 185-191

[9] LiQ.-C.The theoretical foundation of casting forming [M], 1982, Beijing, China Machine Press

[10] WillersB., EckertS., MichelU., HaaseI., ZouharG.. The columnar-to-equiaxed transition in Pb-Sn alloys affected by electromagnetically driven convection [J]. Materials Science and Engineering A, 2005, A402(1/2): 55-65

[11] QiY.-l., JiaG.-l., ZhangG.-zhi.. Effect of electromagnetic stirring on liquid metal fluid flow and solidification structure [J]. Foundry Technology, 2005, 26(2): 118-120

[12] KeisukeF.. In-mold electromagnetic stirring in continuous casting [J]. IEEE Transactions on Industry Application, 2001, 37(4): 1098-1104

[13] MillsK. C., SuY. C., LiZ. S., BrooksR. F.. Equations for the calculation of the thermo-physical properties of stainless steel [J]. ISIJ International, 2004, 44(10): 1661-1668

[14] ZhongY.-b., MengX.-j., NiD., RenZ.-m., DengK., XuK.-di.. Experimental study on purifying molten steel by superimposing rotating magnetic field [J]. Shanghai Metals, 2006, 28(2): 9-14