Analysis of the growth process of crystallized slag rim in 430 stainless steel mold flux
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摘要: 某钢厂430不锈钢采用进口保护渣常常形成过大的渣圈,影响铸坯的质量。为了明晰其渣圈长大原因,采用结晶器渣膜热流模拟仪,制取
1450 ℃条件下430不锈钢保护渣结晶型渣圈,并利用扫描电镜分析其微观结构,以探究渣圈生长过程。同时,使用Factsage软件进行热力学模拟,并与XRD试验结果对比。结果发现:高熔点的硅酸二钙、硅灰石、黄长石和枪晶石优先析出冷凝在器壁上,形成初始结晶型渣圈,占35%;随后,较低熔点的菱硅钙钠石黏附在此层,占20%;最后,夹杂少量霞石的枪晶石逐渐附着在已形成的渣圈上,占45%。通过对这一过程的分析,揭示了430不锈钢保护渣结晶型渣圈的形成机制,为控制渣圈生长提供了理论依据。Abstract: A certain steel plant using imported mold flux for 430 stainless steel often results in excessively large slag rims that affect the quality of the cast slab. To clarify the reasons for the enlargement of the slag rings, this study employed a slab mold slag film heat flux simulator to create a crystallized slag rim for ultra-low carbon protection slag at1450 °C. SEM microstructural analysis was used to explore the growth process of the slag rim. Additionally, thermodynamic simulations using Factsage were conducted and compared with XRD experimental results. The findings revealed that high-melting-point phases dicalcium silicate, wollastonite, feldspar, and gunite preferentially crystallized and condensed on the mold wall, forming the initial crystallized slag rim (35%). Subsequently, lower-melting-point combeite adhered to this layer (20%). Lastly, cuspidine containing minor nepheline gradually deposited on the existing slag rim (45%).Through the analysis of this process, the study elucidated the formation mechanism of the crystallized slag rims in 430 stainless steel mold flux, providing a theoretical basis for controlling the slag rims growth.-
Key words:
- 430 stainless steel /
- crystalline slag rim /
- microstructure /
- growth mechanism
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表 1 430不锈钢成分
Table 1. Composition of 430 stainless steel
% C Si Mn P S Cr Ni N 0.030~
0.0400.250~
0.3500.250~
0.500≤0.030 ≤0.005 16.00~
17.00≤0.400 0.030~
0.050表 2 430不锈钢保护渣成分
Table 2. Composition table of ultra-low carbon mold slag
% 成分 碱度 Al2O3 Fe2O3 F MgO Na2O C-total 测验值 1.16 6.30 1.80 5.80 1.00 10.30 2.50 表 3 430不锈钢保护渣降温过程中析出物质
Table 3. Precipitated substances during cooling of 430 stainless steel mold flux
温度/℃ 析出物质成分 1450 ~1315 Slag-liq cooling 1315 ~1167 Ca2SiO4 1167 ~1099 Bredigite+ Ca2SiO4 1099 ~1042 Bredigite + Ca2SiO4 + Ca4Si2F2O7 1042 ~1000 Bredigite + Ca3Si2O7+ Ca4Si2F2O7 1000 ~992Na2CaAl4O8+Bredigite + Ca3Si2O7+ Ca4Si2F2O7 992~921 Combeite + Na2CaAl4O8 + Ca4Si2F2O7 921~829 Combeite + Na2CaAl4O8 + Na2CaSiO4 829~815 Combeite + Na2CaAl4O8 + NaF 815~797 Combeite + Na2CaAl4O8 + NaF + Na2MgSiO4 797~793 Nepheline+Combeite+Na2CaAl4O8+NaF + Na2MgSiO4 793~792 Nepheline + Combeite + NaF+ Na2MgSiO4 + Ca4Si2F2O7 -
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