Application of microcrystalline complex modifiers for steel ladle treatment. Part 1. The role of nonmetallic inclusions in steel quality forming

2021 ◽  
Vol 77 (3) ◽  
pp. 295-309
Author(s):  
V. A. Golubtsov ◽  
I. V. Ryabchikov ◽  
I. V. Bakin ◽  
A. Ya. Dynin ◽  
O. N. Romanov ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Nonmetallic Inclusions ◽  
Steel Production ◽  
Good Alternative ◽  
Ladle Treatment ◽  
Steel Ladle ◽  
Long Time ◽  
Negative Effect ◽  
Favorable Conditions ◽  
Inclusions In Steel

Contamination of steel by nonmetallic inclusions (NI) has a negative effect on mechanical characteristics of metal used under no favorable conditions. Conditions of NI forming in the process of steel smelting, ladle treatment and casting considered. It was shown that it is impossible to get rid of many NI. However, the task of forming less “harmful” NI having minimal effect on the decrease of finished products indices is quite practicable. To refine steel of NI it is reasonable to accomplish operations in a melt to modify NI morphology from dangerous acute-angled aluminous to globular oxide-sulphide. This task can be solved by introduction into metal complex modifiers comprising calcium, barium, strontium and rare earth metals. Addition of complex modifiers is a good alternative to complicative and long-time operations to decrease NI general content to lower levels, for example, by long-time metal ladle treatment. Application of the method enables in some situation to avoid expensive operations related to deep metal desulphuri zation and its dehydronization. Clean steel production becomes considerably easier at application of multicomponent alloys, obtained by a technology of accelerated crystallization. Application of such compositions results in forming globular oxide and oxide-sulphide compounds, as well as eutectics with low-melting point, which are comparatively quickly removed out of liquid metal. At that due to decreasing of liquation processes forming in the liquid metal, higher quality of large ingots and work-pieces, obtained from 420 t mass ingots can be reached.

scholarly journals Efficiency evaluation of physical and chemical methods of steel quality improvement

2019 ◽  
Vol 75 (6) ◽  
pp. 695-705
Author(s):  
V. A. Golubtsov ◽  
I. V. Bakin ◽  
A. A. Tokarev ◽  
I. V. Ryabchikov ◽  
G. G. Mikhailov
Keyword(s):  
Quality Improvement ◽  
Liquid Metal ◽  
Ladle Treatment ◽  
Steel Ladle ◽  
Chemical Methods ◽  
Steel Quality ◽  
Wide Range ◽  
Metal Treatment ◽  
Metal Products ◽  
Physical And Chemical

To achieve a high quality of steel a wide range of liquid metal treatment methods applied. The choice of method is often determined by technological possibilities of the metal products manufacturer. An analysis of various physical and chemical methods of steel quality improvement accomplished, which allowed making a choice of liquid metal treatment method, depending on existing tasks and technological possibilities. It was shown, that physical and chemical methods of metal products quality improvement apart from other methods of ladle treatment have additional possibilities to effect steel quality. In some cases, those methods allow to exclude a complicated technological equipment, to reduce considerably expenses for liquid metal ladle treatment and to improve the products quality. A comparative analysis of methods of steel ladle treatment accomplished. Data on the active elements behavior in the iron based melts quoted. The mechanism of modification, inoculation and steel micro-alloying processes described. Data on industrial application those processes to obtain quality metal products quoted. It was shown, that melt modification process allows changing the metal structure, decreasing its impurity by nonmetallic inclusions, to change the nature, form and character of their distribution in the metal. Effect of the micro-alloying has a long-term and stable character of alloying elements impact and allows effecting the steel quality, changing steel chemical and phase compositions. Inoculation allows considerable increasing the ability of nuclei formation and effect the metal crystallization parameters due to formation of ready crystallization centers in the solidifying alloy. Base on analysis results a conclusion made, that physical and chemical methods of impact on steel allow purposefully effecting the metal products properties, reduce the cost of metal treatment and increase its quality.

scholarly journals CONTENT MODIFICATION OF DIFFERENT TYPES OF NONMETALLIC INCLUSIONS DURING LOW-CARBON IF STEEL LADLE TREATMENT

2019 ◽  
Vol 62 (5) ◽  
pp. 345-352 ◽  
Author(s):  
D. V. Gorkusha ◽  
K. V. Grigorovich ◽  
A. V. Karasev ◽  
O. A. Komolova
Keyword(s):  
Nonmetallic Inclusions ◽  
Ladle Treatment ◽  
Gas Analysis ◽  
Metallographic Analysis ◽  
Steel Ladle ◽  
Interstitial Free ◽  
If Steel ◽  
Low Carbon ◽  
Metallic Inclusions ◽  
Fractional Gas Analysis

Development of advanced materials for the automotive industry allows us to produce a lighter body without losing strength characteristics of the structure. It became possible by the creation and subsequent introduction into the production of such steel grades as IF (Interstitial Free) – steel with no interstitial solute atoms to strain the solid iron lattice and IF-BH (Bake Hardening) – steel with hardening during hot drying. The article provides a brief overview of the history of the emergence of IF steel and the current situation in the production of it in Russia. One of the quality criteria for steels of IF grades is purity of the metal by non-metallic inclusions (NMI), which negatively affect the plastic properties of the material, lead to the formation of surface defects of flat rolled products and reduce the manufacturability due to a decrease in the casting speed of steel, as they cause overgrowing of steel casting nozzles. The article presents investigation results of the content, composition, size and morphology of non-metallic inclusions (NMI) in the metal samples taken at all stages of ladle treatment and casting of IF steel grade production using quantitative metallographic analysis, electrochemical dissolution (ED) followed by X-ray microanalysis of isolated inclusions, Auger electron spectroscopy and fractional gas analysis (FGA). As a result of the analysis of inclusions in the studied samples using a scanning electron microscope, according to morphological features, five characteristic types of inclusions were identified, which reduce the performance properties and strength cha racteristics of the materials produced from them. Results of the analysis of nonmetallic inclusions in metal samples obtained by the ED method are in good agreement with the results of the determination of oxide nonmetallic inclusions by the FGA method. The method of fractional gas analysis shows the dynamics of changes in the content of various types of oxide nonmetallic inclusions during the secondary (ladle) treatment of steel. It is shown that application of the FGA method allows to make analysis of causes of the harmful NMI formation in the metal and to correct operations at ladle treatment.

Study of effect of wheel steel microalloying by calcium and barium on nonmetallic inclusions modification

2020 ◽  
Vol 76 (6) ◽  
pp. 564-572
Author(s):  
A. V. Gaivoronoskii ◽  
N. V. Pavlova
Keyword(s):  
Service Life ◽  
High Speed ◽  
Nonmetallic Inclusions ◽  
Ladle Treatment ◽  
Wheel Steel ◽  
Rolling Stock ◽  
Steel Ladle ◽  
Treatment Technology ◽  
Cored Wire ◽  
Globular Form

The increase in freight cars axis loads, dynamic loads and heat impact on the wheels, change of other factors, stipulated by railway transport traffic intensification lead to considerable decrease of service life of solid-rolled wheels. To increase the service life of them, provision of the transport metal purity in non-deformed oxide nonmetallic inclusions with high content of Al2O3, decrease of general steel pollution by nonmetallic inclusions by micro-alloying and modification is an actual task. The purpose of the study was elaboration of wheel steel ladle treatment technology, including the steel micro-alloying and modification by barium-containing alloys to create material, which could meet high operation requirements, made to the railway wheels of new generation, intended to operate under increased axis loads conditions at the modern high-speed rolling-stock. It was shown, that replacement of everywhere applied silicocalcium by barium-based alloys is one of perspective ways of modification mechanism perfection. Results of industrial tests of micro-alloying of wheel steel by barium during ladle treatment presented. It was shown, that application for modification of cored wire with silicobarium filler instead of cored wire with silicocalsium filler СК-30, enabled to transform the nonmetallic inclusions into globular form practically completely, to raise the steel purity for all kinds of inclusions in both middle and maximum points range and to refine to some extent the grain size by 1-2 points. In the pilot metal at the depth of 40 mm from the surface, the gain was somewhat finer and more uniform (number 7), comparing with the existing technology (number 5-6). The pollution of the pilot metal by nonmetallic inclusions meets requirements of GOST 10791—2011 for category A and those of the standard EN 13262: 2004+А2:2011 for category 1.

scholarly journals Evolution of the Numerical Model Describing the Distribution of Non-Metallic Inclusions in the Tundish

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2229
Author(s):  
Tomasz Merder ◽  
Jacek Pieprzyca ◽  
Marek Warzecha ◽  
Piotr Warzecha ◽  
Artur Hutny
Keyword(s):  
Numerical Model ◽  
Liquid Steel ◽  
Nonmetallic Inclusions ◽  
Steel Production ◽  
Cfd Modeling ◽  
Water Model ◽  
Working Space ◽  
Production Stages ◽  
Steel Flow ◽  
Flow Controllers

Continuous casting is one of the steel production stages, during which the improvement in the metallurgical purity of steel can be additionally affected by removing nonmetallic inclusions (NMIs). This can be achieved by means of various types of flow controllers, installed in the working space of the tundish. The change in the steel flow structure, caused by those flow controllers, should lead to an intensification of NMIs removal from the liquid metal to the slag. Therefore, it is crucial to understand the behavior of nonmetallic inclusions during the flow of liquid steel through the tundish, and particularly during their distribution. The presented paper reports the results of the modeling studies of NMI distribution in liquid steel, flowing through the tundish. CFD modeling methods—using different models and computation variants—were employed in the study. The obtained CFD results were compared with the results of laboratory tests (using a tundish water model). The results of the performed investigations allow us to compare both methods of modeling; the investigated phenomena were microparticle distribution and mass microparticle concentration in the model fluid. The validation of the CFD results verified the analyzed computation variants. The aim of the research was to determine which numerical model is the best for describing the studied phenomenon. This will be used as the first phase of a larger research program which will provide for a comprehensive study of the distribution of NMIs flowing through tundish steel.

Use of immunocorrectors in patients with chronic lymph leukemia

1986 ◽  
Vol 67 (2) ◽  
pp. 99-101
Author(s):  
V. Ya. Shustov ◽  
N. A. Afanasyeva ◽  
P. P. Kuznetsov ◽  
A. K. Myshkina
Keyword(s):  
Immune System ◽  
Outpatient Treatment ◽  
Infectious Complications ◽  
Chronic Lymphatic Leukemia ◽  
Cytostatic Drugs ◽  
Ability To Work ◽  
Lymphatic Leukemia ◽  
Long Time ◽  
Negative Effect

Chronic lymphatic leukemia is second only to acute leukemia in the frequency of infectious complications. In most cases, severe infectious complications are the cause of death in these patients. Modern chemotherapy makes it possible to preserve the ability to work and the life expectancy of patients for a long time. However, the negative effect of cytostatic drugs on the already altered immune system leads to an even greater suppression of immunity and an increase in the number of infectious complications. The search for new ways to combat infections has shown the advisability of long-term outpatient treatment with antibacterial drugs.

Formation of Nonmetallic Inclusions during Ladle Treatment of Pipe Steels

2021 ◽  
Vol 2021 (7) ◽  
pp. 864-873
Author(s):  
A. Yu. Em ◽  
O. A. Komolova ◽  
A. M. Pogodin ◽  
K. V. Grigorovich
Keyword(s):  
Nonmetallic Inclusions ◽  
Ladle Treatment ◽  
Pipe Steels

scholarly journals Long-term investigation of phosphorus removal by iron electrocoagulation in small-scale wastewater treatment plants

2018 ◽  
Vol 78 (6) ◽  
pp. 1304-1311 ◽  
Author(s):  
I. Mishima ◽  
M. Hama ◽  
Y. Tabata ◽  
J. Nakajima
Keyword(s):  
Wastewater Treatment ◽  
Phosphorus Removal ◽  
Wastewater Treatment Plants ◽  
Phosphorus Release ◽  
Small Scale ◽  
Operational Conditions ◽  
Long Time ◽  
Negative Effect ◽  
Iron Electrolysis

Abstract Small-scale wastewater treatment plants (SWTPs), called Johkasou, are widely used as decentralized and individual wastewater treatment systems in sparsely populated areas in Japan. Even in SWTPs, nutrients should be removed to control eutrophication. An iron electrolysis method is effective to remove phosphorus chemically in SWTPs. However, it is necessary to determine the precise conditions under which phosphorus can be effectively and stably removed in full scale SWTPs for a long period. Therefore, long-term phosphorus removal from SWTPs was investigated and optimum operational conditions for phosphorus removal by iron electrolysis were analyzed in this study. Efficient phosphorus removal can be achieved for a long time by adjusting the amount of iron against the actual population equivalent. The change of the recirculation ratio had no negative effect on overall phosphorus removal. Phosphorus release to the bulk phase was prevented by the accumulated iron, which was supplied by iron electrolysis, resulting in stable phosphorus removal. The effect of environmental load reduction due to phosphorus removal by iron electrolysis was greater than the cost of power consumption for iron electrolysis.

scholarly journals INTEGRATED SYNOPTICAL METHOD FOR CALCULATING ASSIMILATION CAPACITY OF SEA WATERS

2017 ◽  
pp. 115-120
Author(s):  
Hikmat Hamid oglu Asadov ◽  
Sima Ajdar gizi Askerova
Keyword(s):  
Sea Water ◽  
Water Masses ◽  
Optimum Regime ◽  
Optimization Task ◽  
Maximum Value ◽  
Long Time ◽  
Negative Effect ◽  
Optimum Order ◽  
Assimilation Capacity ◽  
The Given

Pollution of sea waters is one of major attributes of coastal industrial centers and the norming of such emissions is one of major countermeasures. The assimilation capacity of sea waters is a major factor relevant at norming and planning of outflows into sea waters. At present time the synoptical method has been developed, which doesn’t require carrying out long time and repeated observing of the level of pollution of sea waters. This method has formed the basis for developing the integrated synoptical method for calculating sea water assimilation capacity. The suggested method provides for division of the sea waters into separated homogenous water masses. The aim of the study is to develop an inverse integrated synoptical method allowing synthesizing of such an optimum order for loading separate water masses with pollutants upon, at which the calculated total value of assimilation capacity would reach its maximum. The article shows the possibility of utilization of known synoptical method for determining assimilation capacity of sea waters in the inverse order, i.e. for calculating the maximum value of pollutant put into the fixed zone of sea waters, upon a condition of reaching the given amount of assimilation capacity and absence of essential negative effect on ecosystem. The task of calculating an optimum regime function of discrete type, upon which the integrated value of assimilation capacity would reach the maximum value, has been formulated. The solution of analogue equivalent of the formed optimization task is carried out using the Euler equation for a non-conditional variation optimization task, taking into account the accepted limitation condition. The recommendations on optimum loading of different sea water zones with determined type of pollutant have been given.

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