YU Xiong
,
WEN Guanghua
,
TANG Ping
,
MA Fanjun
,
WANG Huan
钢铁研究学报(英文版)
Because of the addition of significant quantities of Al and Mn, the great challenge of casting 20Mn23Al non-magnetic steel is to design a mold slag that is chemically compatible with this steel chemistry. In this paper, a new mold slag with low melting point, low basicity was proposed. The initial slag (the base mold slag) and two corresponding spent mold slag (8min slag and 15min slag), which was sampled from the caster after 8 minutes and 15minutes of casting, were investigated, the changes of mold slag composition and properties of molten slag were discussed. The results showed that:(i) The slag quickly changed in chemistry to a slag that contained a low quantity of silica and a higher quantity of alumina, and the basicity increased obviously; (ii) Heat flux density through the slag film decreased appreciably with the time increase; (iii) Mold slag used for non-magnetic steel precipitated CaF2 crystals; (iv) The slab has good surface quality with not occurrences of longitudinal face cracks and slag inclusions; (v) The Al2O3 content in the molten slag pool increased with time, and Al2O3 concentration of the pool can be regarded as being in a practically equilibrium state after about 600sec.
关键词:
Non-magnetic steel;Continuous casting;Mold slag;Viscosity;CaF2
YU Xiong
,
WEN Guang-hua
,
et al
钢铁研究学报(英文版)
Due to its high content in the Al-TRIP steel, [Al] reacts with (SiO2) in the mold slag during the casting process, which results in the increase of w(Al2O3)/w(SiO2) ratio and the Al2O3 content, respectively, the characteristic of heat transfer through the slag film is then changed, which effects the smooth operation of the continuous casting process. In this paper, the mold slag simulator was used to study the change tendency of the heat flux density through slag film and the results were discussed, at the same time, the crystals in the 15# slag were characterized by BSE and XRD. The results obtained show that:(i) Heat flux density decreases with the increase of w(Al2O3)/w(SiO2) ratio; (ii) Heat flux density increases with the increase of Li2O and/or B2O3 content in the mold slag which contain 30% Al2O3; (iii) Compared with the heat flux density of common slag of peritectic steel, an appropriated mold slag contain 4% B2O3 and 4% Li2O is designed. The heat flux density is 0.645MW•m-2 when w(Al2O3)/w(SiO2)=1.46. (iv) In the equilibrium state, mold slag used for Al-TRIP steel precipitates CaF2 crystals.
关键词:
TRIP steel;heat flux density;w(Al2O3)/w(SiO2) ratio;Li2O;B2O3
