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1.
I. I. Lube A. A. Pecheritsa I. V. Neklyudov I. G. Rodionova A. I. Zaitsev L. G. Marchenko A. V. Emel'yanov V. I. Stolyarov 《Metallurgist》2005,49(7-8):269-275
The main reason for the accelerated local corrosion of tubes is contamination of the steel by corrosion-active nonmetallic
inclusions (CANI), which determine the metallurgical properties of tube steel in terms of their corrosion resistance. Studies
have shown that there are two main types of corrosion-active nonmetallic inclusions: CANI1 — inclusions based on calcium aluminates; CANI2 — complex inclusions that contain calcium sulfide. In order to master to production of tubes of steel 20-PKS at the Volga
Pipe Plant (VTZ), a study was made of the effect of the parameters of out-of-furnace treatments on the contamination of steel
by CANI.
1. The mechanisms and main sources of formation of CANI in tube steels made by the VTZ were determined. The main reasons for
the formation of CANI1 in furnace slag containing thermodynamically active CaO are mixing of the metallic and slag phases during the argon blow
and the simultaneous introduction of additions to correct the chemical composition of the steel. Inclusions of the CANI2 type may be formed by deoxidation operations carried out with suboptimal proportions of added aluminum and calcium (lime).
2. The following measures are recommended to ensure that steel 20-PKS made by the VTZ is clean with respect to both types
of CANI:
• optimize the composition of the ladle slag (increase the average content of Al2O3, increase the average content of SiO2 as much as possible, and in any case decrease the average concentration of CaO);
• keep the mass ratio of added CaO to added Al within the range 1.5–2;
• continue the argon blow done after addition of the last batch of ferroalloys for at least 15–20 min;
• ensure that the intensity of the blow is at least 0.5–1.5 m3/min.
3. Vacuum-degassing steel in the ladle after treatment on a ladle-furnace unit makes it possible to distribute the CANI more
uniformly over the volume of the steel.
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Translated from Metallurg, No. 7, pp. 38–42, July, 2005. 相似文献
2.
以北兴特钢的高炉煤气双蓄热式钢包烘烤器为背景,采用ANSYS数值模拟预测烘烤情况,分析双蓄热式钢包烘烤器优点,并得出入口射流角度20°左右最佳。 相似文献
3.
4.
E. Kh. Shakhpazov A. I. Zaitsev A. A. Nemtinov S. D. Zinchenko I. G. Rodionova S. V. Efimov N. A. Rybkin N. G. Shaposhnikov 《Russian Metallurgy (Metally)》2007,(1):1-9
The main trends in the development of the ladle treatment of steel have been analyzed. The most complex problem is shown to be the formation of nonmetallic inclusions having a certain type and a low concentration. The main parameters of the ladle treatment of steel that control the type and amount of nonmentallic inclusions in ready products are analyzed using the data of industrial heats, laboratory experiments, and physicochemical simulation and computation. The principles of control of steel purity in nonmetallic inclusions are formulated, and the main trends in the development of the concepts of nonmetallic inclusions are determined. 相似文献
5.
Mathematical simulation of fluid dynamics during steel draining operations from a ladle 总被引:2,自引:0,他引:2
O. Davila L. Garcia-Demedices R. D. Morales 《Metallurgical and Materials Transactions B》2006,37(1):71-87
Fluid flow dynamics during ladle drainage operations of steel under isothermal and nonisothermal conditions has been studied
using the turbulence shear stress transport k-ε model (SST k-ω) and the multiphase volume of fluid (VOF) model. At high bath levels, the angular velocity of the melt, close to the ladle
nozzle, is small rotating anticlockwise and intense vertical-recirculating flows are developed in most of the liquid volume
due to descending steel streams along the ladle vertical wall. These streams ascend further downstream driven by buoyancy
forces. At low bath levels, the melt, which is close to the nozzle, rotates clockwise with higher velocities whose magnitudes
are higher for shorter ladle standstill times. These velocities are responsible for the formation and development of a vortex
on the bath free surface, which entrains slag into the nozzle by shear-stress mechanisms at the metal-slag interface. The
critical bath level or bath height for this phenomenon is 0.35 m (in this particular ladle design) for a ladle standstill
time of 15 minutes and decreases with longer ladle standstill times. At these steps, the vertical-recirculating flows are
substituted by complex horizontal-rotating flows in most of the liquid volume. Under isothermal conditions, the critical bath
level for vortex formation on the melt free surface is 0.20 m, which agrees very well with that determined with a 1/3 scale
water model of 0.073 m. It is concluded that buoyancy forces, originated by thermal gradients, as the ladle cools, are responsible
for increasing the critical bath level for vortex formation. Understanding vortex mechanisms will be useful to design simple
and efficient devices to break down the vortex flow during steel draining even at very low metal residues in the ladle. 相似文献
6.
E. Kh. Shakhpazov I. G. Rodionova O. N. Baklanova A. I. Zaitsev D. A. Burko A. D. Gorin S. D. Zinchenko 《Metallurgist》2006,50(1-2):65-70
It is shown that the corrosion resistance of automobile sheet can be improved by ensuring that steels of this type have a
low content of corrosion-active nonmetallic inclusions (CANI). The main mechanisms responsible for the formation of CANI in
automobile sheet have been established, and recommendations have been developed to reduce their concentration in this product
• optimize the deoxidation processes that are used by ensuring that the proportions of the additions made to the steel are
consistent with the composition of the ladle slag and that certain key temperature-time parameters of these processes are
maintained
• control the composition of the ladle slag to prevent the formation of solid phases in the slag and their transfer to the
metal; certain conditions must also be observed in the argon blow and the introduction of the addtions.
Use of the above recommendations to make automobile sheet and tube steels cleaner with respect to their content of CANI and
thus help optimize out-of-furnace treatments at metallurgical and pipe plants will make it possible to improve the corrosion
resistance of metal products used in automotive manufacturing.
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Translated from Metallurg, No. 2, pp. 45–48, February, 2006. 相似文献
7.
Pengcheng Yan Shuigen Huang Lieven Pandelaers Joris Van Dyck Muxing Guo Bart Blanpain 《Metallurgical and Materials Transactions B》2013,44(5):1105-1119
The ladle treatment of a 18 pct Cr-9 pct Ni stainless steel, with desulfurization as its main purpose, was simulated on a laboratory scale. The influence of the top slag chemistry on the steel cleanliness was evaluated. A higher steel cleanliness was obtained with an optimized lime-alumina-based slag than with a lime-fluorspar-based slag. The inclusions were found to be mainly in the form of oxysulfide; the alumina content in the inclusions first increased and subsequently showed a slow drop, while the sulfide content decreased during the treatment. The equilibrium between steel and inclusions was found to be more easily reached than that between slag and steel. A slag–steel kinetic model was used to predict the steel chemistry evolution during the treatment. Furthermore, a slag–steel–inclusions interaction kinetic model was developed to calculate the change of alumina content in the inclusions during the ladle treatment. The sulfide content of inclusions was also calculated and compared with the measured values. 相似文献
8.
9.
Water model studies in a pilot scale ladle (D = 1.12 m andL = 0.93 m) were carried out to investigate the subsurface motion of both buoyant and sinking additions during the CAS (com-position
adjustment by sealed argon bubbling systems) alloy addition procedure in steelmaking. This technique involves placing a refractory
baffle around a rising gas/liquid plume within a stirred ladle of steel. Alloy additions are then made by projecting them
into the slag-free region of steel within the baffled region.
It was found that such particles while moving through the upwelling two-phase plume region can experience a significant reduction
in drag forces, causing buoyant particles to penetrate more deeply than anticipated for a homogeneous fluid. Therefore, considering
reduced drag on particles penetrating the upwelling gas liquid plume region, predictions were made for the trajectories of
spherical-shaped particles using Newton’s law of motion. Predictions were in very reasonable agreement with those measured.
Incorporating the velocity fields in industrial size vessels already reported by the present authors, trajectories of spherical-shaped
additions (diameter ∼ 80 mm) in a 150-ton ladle during CAS operations were then predicted. The industrial implications of
such trajectories, together with the alloy’s dissolution and dispersion behavior, were also analyzed. Finally, advantages
of the CAS alloy addition procedure over conventional methods, in terms of the recovery rates of buoyant additions, are discussed. 相似文献
10.
A. N. Smirnov A. L. Podkorytov V. G. Klimov S. G. Solovykh A. V. Kravchenko A. G. Kovalenko 《Steel in Translation》2009,39(11):995-999
Continuous steel-bar casting on a multistrand machine in superlong series is limited by the working-layer wear of the intermediate
ladle’s lining within the slag band and the region of jet incidence. The lining life may be significantly increased by using
high-strength concrete tundishes of special geometric shape, taking account of the specific ladle and the casting conditions.
A fundamentally new metal-intake design for the casting of superlong series at multistrand continuous bar-casting machines
is investigated. In the converter shop at OAO Enakievskii Metallurgicheskii Zavod, a casting series of maximum length 64 melts
proves possible. This corresponds to the casting of 9300 t of steel from a single intermediate ladle. For optimal organizational
and technological conditions, increase in this characteristic by a factor of 1.5–1.6 may be expected. 相似文献
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12.
钢包红包出钢率的提高对优化钢包热状态、降低转炉出钢温度以及保证铸机恒拉速浇注都有重要意义。首先分析了炼钢厂钢包周转过程,然后建立了钢包周转过程的仿真模型,运行仿真模型并分析了空包时间、热修时间和修包包龄等因素对红包出钢率的影响,特别研究了钢包周转率与红包出钢率的关系。仿真结果表明:红包出钢率随空包时间增加而降低;日产45炉典型钢种时,随着热修时间增加,红包出钢率由94%减少到45%;修包包龄越高,红包出钢率增加越明显;同时,随着红包出钢率提高,钢包周转率在一定程度上也有所提高。仿真结果对炼钢厂提高红包出钢率和优化能源消耗具有重要指导意义。 相似文献
13.
B. A. Sarychev D. N. Chigasov A. F. Sarychev O. A. Nikolaev S. V. Meshcherov 《Metallurgist》2007,51(1-2):38-40
Results are presented from trial heats of low-alloy steel that were made with the addition of different amounts of lump ferrochromium
to the ladle during tapping. The amounts added were sufficient to give the steel a final chromium content within the range
from 1.1 to 2.3%.
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Translated from Metallurg, No. 1, pp. 51–52, January, 2007. 相似文献
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15.
《钢铁冶炼》2013,40(6):514-518
AbstractThe present study was carried out to investigate the impact of slag– refractory lining reactions on the formation of inclusions during ladle treatment of steel. The experiments were conducted on an industrial scale in the ladle at Uddeholm Tooling AB in Hagfors, Sweden. The inclusion chemistry and population during ladle treatment were studied along with the composition of the ladle glaze, taken from the ladle lining. The inclusions in the steel were classified into four groups according to the Swedish standard SS 111116. SEM/EDS analyses were carried out to identify the phases present in both the inclusions and the ladle glaze. The number of inclusions in the steel before deoxidation was found to increase with the ladle age, i.e. the number of times the ladle had been in use. A similar increase was also found after vacuum degassing and before casting. A great portion of inclusions before casting was found to be supplied by ladle glaze. This observation was further confirmed and explained by thermodynamic analysis. The present results show that ladle glaze is a major source of inclusions in the ladle at Uddeholm Tooling. 相似文献
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17.
提高LF精炼钢包寿命的措施 总被引:1,自引:0,他引:1
精炼温度高造成渣线侵蚀严重以及炉渣对耐火材料的侵蚀,是影响精炼钢包寿命的主要原因。石横特钢厂采取稳定精炼初始温度;加强中间包烘烤;采用埋弧渣技术,制定合理的分钢种精炼温度等措施,使精炼钢包的平均使用寿命比48炉次提高到53炉次,耐火砖消耗降低了0.79kg/t钢。 相似文献
18.
Yu. A. Samoilovich 《Steel in Translation》2010,40(2):134-140
The removal of alumina particles from steel is considered for two configurations of a (90–100)-t intermediate ladle. Mass
transfer is analyzed on the basis of simultaneous solution of the convective-diffusion equations of the inclusions in the
melt and equations describing melt flow within the ladle, taking account of turbulence. An innovation in the assessment of
the mass-transfer coefficient between the alumina particles and the refining flux is the concept of wave flow of a thin liquid-flux
film as it interacts with the rough surface of the sintered slag. The removal of alumina particles (10–100 μm) from the metal
is assessed. 相似文献
19.
Steel 20Mn23AlV is a type of high aluminum steel with a very low ladle free-opening rate. The aluminum composition of 20Mn23AlV ranges from 1. 6% to 2. 45%,which is significantly higher than other types of steel.According to the real condition of 40 t ladle in steel-making plant of Baosteel Special Steel Company,previous works show that the key factors affecting the ladle free-opening rate of high aluminum steel in continuous casting are: sand material,accessories baking,ladle nozzle cleaning,the process and amount of adding sand,and the rate of argon stirring during refining. Therefore,improving the ladle filler sand quality,baking all of the raw materials,controlling the addition of ladle filler sand,cleaning the ladle nozzle,and optimizing argon stirring during the refining process can resolve the problem of a low ladle free-opening rate of high aluminum steel caused by the long ladle time of liquid steel. 相似文献