RESEARCH THE INFLUENCE OF COMPONENTS CARBON OXIDE COMPOSITION ON STRUCTURE FORMED METAL

The article discusses the possibility of replacing traditional charge materials for steel smelting with an oxide-carbon composition (scale-carbon briquettes) made from metallurgical waste. The possibility of replacing cast iron with briquettes for melt carburization is presented.

Coefficient of local loss of mechanical energy of the flow for a ­mixture of charge materials

Purpose. To determine the dependence of the coefficient of local losses of mechanical energy of flow of a two-component mixture of charge material on its depth, content of components, and average equivalent diameter of particles in the case of their free-dispersed motion. Methodology. The value of the coefficient of local losses of mechanical energy was determined by the value of the hydraulic resistance of the fluid during its movement in open channels and pipes. In this paper, methods were used of comparative analysis, mathematical modeling and forecasting of dynamic processes in the flow of granular material. Findings. Based on the results of theoretical studies, a mathematical model was obtained, the use of which allows calculating the coefficient of local losses of mechanical energy for the flow of a two-component mixture of charge materials with agglomerate particle sizes from 15 to 50 mm, pellets from 6 to 12 mm, coke from 10 to 60 mm. The developed model with satisfactory accuracy makes it possible to evaluate the movement of the charge from the indicated materials along the paths of the charging devices of blast furnaces at a speed in the range from 1.5 to 20 m/s and to determine the trajectories of the mixture of charge materials on the top with an accuracy of 0.2 m. It is noted that the calculation of the above coefficient by the known techniques is not accurate enough, which is associated with the uncertainty in the choice of a single average equivalent diameter of the particles of the two-component charge. Comparative analysis of the developed model with the known models and experimental data indicates that the accuracy of calculating the dynamic parameters of a two-component flow of charge materials using the developed model increases by 510% in comparison with calculations using the previously known models. Originality. For the first time, regularities of changes in the coefficient of internal mechanical losses of a two-component flow of charge materials from its depth, content of components, average equivalent particle diameters when moving along the paths of charging devices of blast furnaces have been established. Practical value. Mathematical dependencies have been developed and can be used to determine the technological parameters of the charge of a modern blast furnace with different characteristics of the granulometry of the charge and the ratios of its components. This will increase the accuracy of predicting the course of the process under consideration, the degree of automation of the control systems for the technological process of the charge supply of blast furnaces, will make it possible to use expensive charge materials more efficiently, reduce energy consumption and reduce the harmful impact on the environment.

MASTERING CHROMIUM-BASED LIGATURES IN SMELTING HEAT-RESISTANT NICKEL ALLOYS AND STEELS

The rapid rise in prices for charge materials used for smelting heat-resistant nickel alloy and steels leads to a significant rise in the cost of the final product. In order to curb the rise in prices for semi-finished products FSUE «VIAM» together with metallurgical plants of the industry, is carrying out work on testing and introducing new types of charge materials that can replace the currently used high-frequency materials. The article discussed the materials tested instead of those currently used in the smelting of steels and alloys containing chromium, tungsten and molybdenum, produced at domestic enterprises from domestic raw materials.

Assessment of Pyrometallurgical Scheme Options of Red Mud and Scale Co-processing

The analysis of various options for the use of alumina production wastes (red mud) and oiled scale using various methods of agglomeration to produce conditioned commercial iron is presented. Co-processing utilization of red mud and oiled scale allows to obtain raw materials with an iron content of more than 50%, which meets the modern requirements for charge materials for use in the blast furnace process. The calculation analysis carried out using a mathematical model of blast furnace process, allowed to determine the optimal proportion of the iron-containing material for the partial replacement of charge materials without reducing the technical and economic indicators of blast furnace smelting. Keywords: Bayer process, red mud, oiled scale, mathematical model, blast furnace process, metallurgical properties, complex utilization

Chunky Graphite in Low and High Silicon Spheroidal Graphite Cast Irons–Occurrence, Control and Effect on Mechanical Properties

Chunky graphite appears easily in heavy-section spheroidal graphite cast irons and is known to affect their mechanical properties. A dedicated experiment has been developed to study the effect of the most important chemical variables reported to change the amount of chunky graphite, namely the content in silicon and in rare earths. Quite unexpectedly, controlled rare earths contents appear beneficial for decreasing chunky graphite when using standard charge materials. Tin is shown to decrease chunky graphite appearance and it is evidenced that this effect is not related to rare earths. Finally, the effect of tin and antimony are compared and it is noticed that both suppress chunky graphite but also lead to some spiky graphite when no rare earth is added. Chunky graphite negatively affects the room temperature mechanical properties, though much more in the case of low silicon spheroidal graphite cast irons than in high silicon ones. Spiky graphite has been found to be much more detrimental and should thus be avoided.

Estimation of quality of hot pressed briquettes as a type of metallurgical charge materials

The basic principles of construction are formulated in the work and a description of the technological process of hot briquetting of ferrous metal waste as a way of converting fine metal particles into a dimensional semi-finished product of a given size and chemical composition is given. The description of equipment for the implementation of this process with highly efficient non-oxidizing heating and complete safe neutralization of flue gases is given. The results of melting of hot-pressed briquettes in various melting units are presented. It is shown that briquettes cleaned from coolant with a density of 6500–7100 kg/m3 are full-fledged substitutes for bulk scrap. Recommendations and a feasibility study on the feasibility of introducing the hot briquetting process into production at the enterprises of the bearing, machine-building and metallurgical industries, followed by the use of hotpressed briquettes to produce cast billets for their own purposes, are given.