Abstract:Nodulation phenomenon of aluminium deoxidized sulphur-containing QC40 steel in a certain factory was analyzed.By scanning surface electron microscopy and energy spectrum analysis, it was found that the nodules were divided into two layers. The nodules near the inner layer of the nozzle were mainly MgO·Al2O3, high melting point CaO-Al2O3 and low melting point CaO-Al2O3. The nodules in the second layer are mainly MgO·Al2O3, CaO-Al2O3 with high melting point and CaS.The inclusions in the bar are mainly MgO·Al2O3, CaO-Al2O3 with high melting point and CaS inclusions.Analysis that appear this kind of phenomenon of nodular CaS belongs to high melting point is the cause of inclusion, but the liquid steel and wetting angle of 87° (less than 90°), belongs to the wettability of molten steel and inclusion, Al2O3 and MgO style and high melting point CaO-Al2O3 and contact angle of liquid steel is greater than 90°, belongs to the high melting point and inclusion with poor wettability of molten steel, thus the CaS inclusions can only in the second the phenomena.The FactSage software was used to theoretically optimize the calcium treatment process of aluminum deoxidized sulfur-containing steel, and it was believed that by optimizing the calcium treatment process and reducing the secondary oxidation, the nodulation behavior of the immersed nozzle could be reduced or even eliminated.
YANG Shu-feng, WANG Qiang-qiang, ZHANG Li-feng.Formation and modification of MgO·Al2O3 based inclusions in alloy steels[J].Metallurgial and Materials Transactions:B,2012, 43(4):731.
[2]
Cowles B A.High cycle fatigue in aircraft gas turbines-an industry perspective[J]. International Journal of Fracture, 1996, 80(2):147.
[3]
YANG S,WANG Q,ZHANG L,et al.Formation and modification of MgO·Al2O3-based inclusions in alloy steels[J]. Metallurgical and Materials Transactions:B, 2012, 43(4):731.
[4]
Verma N,Pistorius P C,Fruehan R J,et al.Transient inclusion evolution during modification of alumina inclusions by calcium in liquid steel: Part I. background, experimental techniques and analysis methods[J]. Metallurgical and Materials Transactions :B, 2011, 42(4):711.
Sunday Abraham, Rick Bodnar, Justin Raines.Inclusion engineering and the metallurgy of calcium treatment[J]. Journal of Iron and Steel Research. International, 2013, 1(2):1243.
[9]
Salgado U D.Fluid force-induced detachment criteria for nonmetallic inclusions adhered to a refractory/molten steel interface[J]. Metallurgial and Materials Transactions:B,2018,49:1632.
[10]
Sangsuwan P,Tewari S N,Gatica J E,et al.Reactive infiltration of silicon melt through microporous amorphous carbon preforms[J]. Metallurgical and Materials Transactions:B, 1999, 30(5):933.
[11]
Singh S N,Bardes B P,Flemings M C.Solution treatment of cast Al-4.5 pct Cu alloy[J]. Metallurgical and Materials Transactions:B, 1970, 1(5):1383.
[12]
Sasai K, Mizukami Y.Effect of composition of immersion nozzle on occurrence of blister in steel sheet[J]. ISIJ International, 1996, 36(1):45.
[13]
Todoroki H.Effect of compositions of non-metallic inclusions on CC nozzle clogging of a Fe-Cr-Ni-Mo system stainless steel[J]. Tetsu-to-Hagané,2014,100(4):539.
[14]
Katsuhiro S.Mechanism of alumina deposition on alumina grap-hite immersion nozzle in continuous caster[J]. ISIJ,2001,41(11):1331.
[15]
Kusuhiro MUKAI.Effect of refractory materials on inclusion deposition of immersion nozzle in continuous casting and mathematical modeling of inclusion deposition[J].Tetsu-to-Hagané,1999,85:307.
[16]
LONG Mu-jun,ZUO Xiang-jun,ZHANG Li-feng,et al.Kinetic modeling on nozzle clogging during steel billet continuous casting[J]. Transactions of the Iron and Steel Institute of Japan, 2012,50(5):712.