Effect of Slag Protection System and Sample Geometry on Homogeneity of Total Oxygen Content in Samples from Liquid Steel

2011 ◽  
Vol 82 (3) ◽  
pp. 222-229 ◽  
Author(s):  
O.T. Ericsson ◽  
A.V. Karasev ◽  
P.G. Jönsson
Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 554 ◽  
Author(s):  
Feng Wang ◽  
Daoxu Liu ◽  
Wei Liu ◽  
Shufeng Yang ◽  
Jingshe Li

Reoxidation has long been a problem when casting ultra-low oxygen liquid steel. An experimental study of the reoxidation phenomenon caused by Cr2O3-bearing cover flux of Al-killed steel is presented here. MgO-CaO-SiO2-Al2O3-Cr2O3 tundish cover flux with various Cr2O3 contents were used to study the effects of Cr2O3 on total oxygen content (T[O]) and alumina and silicone loss of Al-killed steel at 1923 K (1650 °C). It was found that Cr2O3 can be reduced by Al to cause reoxidation, and the reaction occurs mainly within 2 to 3 min after the addition of the tundish cover flux with 5% and 10% Cr2O3 concentration. T[O] and Al loss increase with higher Cr2O3 concentration flux. Two controlled experiments were also made to investigate the oxygen transported to the steel by the decomposition of Cr2O3. It was calculated that when Al is present in steel, more than 90% of the reoxidation of Cr2O3 is caused by Al, and the rest is caused by decomposition.


2019 ◽  
Vol 74 (3) ◽  
pp. 99-104
Author(s):  
Yu. N. Vodyanitskii ◽  
A. T. Savichev

CORROSION ◽  
1958 ◽  
Vol 14 (1) ◽  
pp. 57-64 ◽  
Author(s):  
D. W. JUENKER ◽  
R. A. MEUSSNER ◽  
C. E. BIRCHENALL

Abstract A study is made of the deep oxidation of iron at high temperatures and in an oxygen atmosphere. Large cavities are always found in specimens whose total oxygen content has been brought to that of FeO. The scale thickness of such specimens, along with other evidence, implies that FeO is plastic in the temperature range in which it is stable, while one or both of the higher oxides is relatively rigid. Evidence is presented which indicates that iron is transported to its surrounding scale with little or no body diffusion path; the mechanism involved is not identified. An expression, analogous to the parabolic rate law for scaling of plane specimens, is developed for application to cylindrical geometry. 3.2.3


2014 ◽  
Vol 540 ◽  
pp. 68-71
Author(s):  
Shuo Ming Wang ◽  
Yan Wang ◽  
Ruo Si Wang

Aimed at the Q195 steel production process in a steel mill, using tracer analysis make system analysis to the process of production and microscopic inclusions content. In the steady casting average T[O] is 117.22ppm, [N] is 22.6ppm, micro inclusions average content is 11.96/mm2, while the average T[O] and [N] in transient casting billet is 161.93ppm and 30.49ppm, micro inclusions averaged content is 16.068/mm2. The total oxygen content in steel on the high side, should strengthen deoxidization. Argon stirring strength is too large, inclusions in casting slab containing tracer element, illustrate the ladle slag, tundish slag, mould protection slag are forming pollution on billet, should reduce the influence of transient casting on the steel quality.


2011 ◽  
Vol 52-54 ◽  
pp. 1681-1686 ◽  
Author(s):  
Yang Li ◽  
Zhou Hua Jiang ◽  
Shi You Yin ◽  
Ying Zhuang ◽  
Ming Li

The variation of non-metallic inclusions and total oxygen contents in different steel grades were investigated by taking samples in steelmaking process, including gear steel, anchor chain steel, hard wire steel, bearing steel and spring steel. The inclusions mainly were Al2O3, MnS, and their composite inclusions in aluminum killed steel at the beginning of LF refining due to addition of FeAl alloy during the tapping from EAF and feeding of Al wire in LF process, and then Al2O3 inclusion changed to the Al2O3 - CaO composite inclusions after feeding of SiCa wire. The inclusions at the beginning of LF refining mainly were MnS, SiC and their composite inclusions in non-aluminum killed steel due to addition of the composite deoxidation and slagging agents (mainly including CaC2 and SiC) when EAF taping, while the inclusions in tundish mainly were MnS, CaO - SiO2 - Al2O3 composite oxide - sulfide inclusions. It is showed that the inclusions in bearing steel and spring steel samples were mainly globular oxide inclusions and silicate inclusions with higher rated results. Therefore, the refining process should be improved to remove globular oxide inclusions. The inclusions in molten steel were controlled by enhancing the diffusion deoxidation process, adjusting and controlling the basicity and composition of refining slags, respectively, and satisfactory results were obtained. The industrial test shows that the total oxygen content of the aluminum killed steel in the test heat after feeding wire reached the minimum value, which indicates that the optimized slag has a strong ability of absorbing Al2O3 inclusions. For non-aluminum killed steel, the total oxygen content was 0.0027 % to 0.0029 % in rolled products. The inclusions in the end of refining and rolled product were small and dispersed composite inclusions, and the separate Al2O3 inclusions can not be found in the non-aluminum killed steel after optimization of the refining process.


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