Foundry Furnace Research Articles

The Effect of Vacuum Forming on the Quality of Refractory Materials

Various designs of furnaces for melting alloys are used in the foundry industry. Regardless of their design, they have one common detail, which is the lining of their interiors with refractory materials. This component in the design of a metal-melting furnace has a very important task—to protect the rest of the furnace assemblies from thermal and mechanical damage. Continuous technical progress and the quality requirements of casting production produce increasingly higher demands for refractory materials in connection with their development as well. The article presents the results of an innovative method of vibratory compaction of refractory material (high-alumina aluminosilicate) using reduced pressure. The analysis presents a comparative study of two methods used for forming refractory materials, i.e., the application of the mentioned innovative method and the classical (standard) method of compaction by vibration only. The effects of the introduced modification in the manufacture of ceramic shapes were evaluated by means of the material’s resistance to thermal shock, linear expansion, and dimensional change due to firing, apparent density, open porosity, and apparent specific gravity, determination of total pore volume and pore size distribution by mercury porosimetry, and slag resistance. The tests performed indicate that the procedure of lowering the pressure during the vibratory compaction of the refractory material creates a more homogeneous structure with a smaller number and size of pores. This makes it possible to improve most of the parameters that determine the quality of the refractories used for the linings of the foundry furnace.

An IT System for the Remote Burden Optimization of Foundry Furnaces

The burden calculations for foundry furnaces are one of the most important steps in preparing the production of liquid casting alloys. These calculations, due to the usually large number of input materials and chemical elements, are realized by numerical methods. These methods are implemented in some spreadsheets, universal mathematical programs or in specialized programs for foundry engineering. The paper describes a computerized system for remote calculations of optimal burden. The technological, economic, and organizational features of implementing IT system have been presented, also taking into account its safety of use.

Effusion Mechanism of α-Layer Formation in Vacuum Casting of Titanium Alloys

The formation of the so-called α-layer when casting titanium alloys significantly impairs the mechanical properties of the metal and leads to the need for additional product surface treatment. It is known that simultaneously with the change in mechanical properties, the composition of the casting surface layer is often changed, and the composition change depth, as a rule, does not coincide with the depth of α-layer formed. The reason for α-layer formation, most often, is considered to be the introduction of foreign elements into the crystal lattice of a metal casting. According to our assumption, the mechanism of α-layer formation is two-stage, and it is associated with an intense diffusive effect on the melt structure in the casting outer layer, resulting from its boiling in vacuum during pouring into porous ceramic shells (CS). The paper suggests possible mechanism for composition changing of the surface α-layer in titanium castings due to the secondary processes of effusion saturation of the metal surface with reverse vapor flows coming from the porous ceramic shell after solidification of the casting. In this case, the primary process is the saturation of the CS pores due to the effusion of metal vapors during the boiling of the poured melt due to the high intrinsic vapor pressure exceeding the pressure in the foundry furnace. Chemical interaction of the alloy component vapors with the CS material leads to the volatile components: silicon, silicon II oxide, zirconium II oxide, saturating the metal surface layer due to reverse secondary effusion. The paper presents experimental results on α-layer formation when casting BT5JI alloy in CS having different composition and porosity. The research results confirm the assumption about both the diffusion mechanism of α-layer formation and the effusion mechanism of changes in its composition.

Comparative analysis of sensors for climate check

Registration and monitoring of climatic conditions is an essential task in many manufacturing processes. These parameters are essential for storing certain types of materials or equipment and also play a significant role in the operation of the device. In this regard, the problem of using specialized recording devices becomes relevant. This paper considers such instruments for recording and monitoring climatic characteristics as testo 608-H1; testo 635; testo 645; TPM 201. Their technical characteristics and measurement ranges have been presented. Also the conclusions about the conditions under which it is better to use a particular device have been drawn. The study found that testo 608-H1 and testo 635 have limited functionality and are mainly used in accommodation units or small warehouses. The testo 645 and TPM 201 devices have more extensive functionality and are used in enterprises in test facilities, production lines, climate chambers, dryers, foundry furnaces, galvanic shops.

Modelling of the thermal state and the melting loss of a graphite electrode in the conditions of the evaporative cooling in the arc furnace

The cost of the graphite electrodes amounts greater proportion in the final value of the finished product. This calls for finding opportunities to reduce the maintenance costs of AC and DC furnaces used in foundries. The aim of the study is the creation of a mathematical model and the analysis of the efficiency of the evaporative cooling method in reducing the amount of the graphite electrodes used in small capacity arc furnaces. The mathematical model and the computer program allow determining the thermal state of the electrode and the melting loss of the graphite, the model is developed for a primarily cylindrical electrode and takes into account: the current passing through an electrode, the time of the electrode being in the electrified furnace, and the parameters of the water evaporative cooling. The paper presents the received data about the melting loss of the graphite per ton of steel against the water consumption during the evaporative cooling. The graphite consumption in the arc furnaces of 10–12 tons’ capacity is reduced by 40 %. The recommended water consumption for the evaporative cooling of electrodes for all types of foundry furnaces is 0.1–0.2 m3/h.

Pollution emission evolution from composite and metal formation in Foundry Industry

The consumption of steel is a major indicator of the rate at which a country is developing. Emerging economies such as China and India markets have developed on the back of products such as steel, aluminum, and alloys. This development have not received much fanfare because of the environmental pollution incurred by the production of this products and at that rapid scale. This paper aims at studying the environmental impact of steel production by identifying the various forms in which pollution occurs in the metal production industry. This study limits itself to understanding the impact of gases evolved from the metal foundry be it from the foundry furnace or the metal mold cast. The study indicates that there is a correlation between the quality of mold cast and the rate of gas emission.

Determination of the Charge Materials Range in Multistage Charge Burden Optimization for Foundry Furnaces

Optimization of charge burden for foundry furnaces lies in determining a percentage or mass (kg, t) of the share of each charge material in the burden with the lowest unit cost. A classic task of charge burden optimization requires a definition of an objective function, which most often defines the cost of the charge burden and a system of constraints, including technological assumptions such as the balance of chemical elements for the required chemical composition of the charge or molten metal, limitations of the mass fraction of the individual elements of the charge, and others. The solution for such an optimization task is a set of starting values for the devices which weigh and proportion the charge materials for a foundry furnace. The consequences of deviations from proper values, causes by inaccurate weighing or proportioning and human error as well, can be limited by using an appropriately designed and implemented multistage optimization algorithm. This article presents a mathematical model of such an algorithm and discussion of its practical application. The algorithm as described below can be an important element of computer-aided decision to be made by employees in the process of batch compilation or automatically control devices dosing individual batch components. An IT system with an implemented algorithm may significantly increase the efficiency of charge preparation for a foundry furnace, guaranteeing its correct chemical composition despite batch materials dosing errors. It will contribute to a significant improvement of economic indicators of liquid metal production, with the effect of boosting the competitiveness of the foundry industry.

Increasing Energy Efficiency of Electric Arc Foundry Furnaces

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Multiwalled boron nitride microtubes (BNMTs) shielding in thermal neutron absorbing

ABSTRACTIn this study, multiwalled boron nitride microtubes (BNMTs) were synthesised from amorphous boron powder in pure nitrogen atmosphere controlled graphite furnace at 1300°C for 6 h with amorphous boron/manganese (IV) oxide (MnO2) catalyst mass ratio of 1/1. It was found that the synthesised BNMTs outer diameters and the lengths vary between 0.68 and 1.57 µm and between 6.79 and 31.23 µm, respectively, by the scanning electron microscope analysis. The surface layer of AISI 1040 steel material was coated with multiwalled BNMTs at 950°C for 4 h in a foundry furnace. Transport phenomena of BNMT molecules on surfaces of the steel were considered by diffusion. Neutrons from obtained 241Am-Be source were irradiated on the 58Fe nuclei. The irradiation properties of the without and with BNMT coated steel materials were studied in the field of gamma emitted by 60Co. The radiation exposure rate of gamma radiation sources used at 1099 and 1291 keV, respectively. The higher peak area was obtained in steel coated with BNMT according to non-coated steel from irradiation results of samples. These results show that BNMT coated steel was more capable for radiation shielding.

Burden Optimisation of Lump Charge Materials for Foundry Furnaces

AbstractCalculation of economically optimum charge burden for foundry furnaces depends on a solution that can be found in the field of mathematical linear programming. A traditional linear optimisation method means looking for continuous variables that can define portion of every charge component.Sometimes, it can be observed that a calculated portion of charge material with a defined lump mass is rounded up, which is wrong because the charge burden prepared in such a way may either show a mistaken chemical composition, or it can entail a significant cost. With charge materials characterised by defined mass lumps, it is recommended to use a modified method of integer linear optimisation.This article contains definitions of a goal function and a system of constraints considering the charge materials as stated above. In addition, a sample calculation has been included hereto to show such optimisation for a selected process of metal melting in a casting furnace.

Structural Characterization and Its Physical Properties of Non-standard A1 Austenite Steel

New austenite stainless steel code-named A1 has been synthesized using the foundry method. The steel was prepared using mineral elements extracted from crude ores in Indonesian mines and commercial scrap materials, in this case ferro scrap, ferro chrome, nickel, manganese, and ferro silicon; all of them were in the granular shape. The starting materials are inserted into an induction foundry furnace that operates on an electromagnetic inductive-thermal system. Moreover, a small quantity of titanium was added to this austenite steel that already has a very low carbon content. The neutron diffraction pattern shows that the material had an fcc crystal structure with lattice parameter of 3.5935 A. Neutron diffraction residual stress and texture measurements were performed on the austenite samples. The residual stress along the [220] crystallographic direction in the A1 alloy is compressive except in the normal direction where it is tensile. Tension as high as -629 MPa was observed in both the axial, transversal and normal directions. No region of high pole densities has been found in the material indicating a weak texture. The average value of the observed hardness is around of 205 on the Vickers scale for original casting sample; and the average hardness value of

Algorithm for Burden Calculation for Foundry Furnaces Using Charge Materials with an Uncertain Composition

Abstract Calculation of charge burden to foundry furnaces by computing the proportions of particular charge materials is a most complicated task as a variety of technological aspects have to be considered. For practical and economic reasons, this problem is typically solved using computer-based optimisation methods, the main criterion being the optimal amount of charge materials related to the lowest costs of the burden. The problem is further complicated when the chemical composition of the charge materials is not accurately defined. So far the calculations of the charge burden were performed in order to work out the detailed melt procedure, which was to be modified and corrected by the trial and error method in subsequent melt processes. An algorithm has been developed for use in calculating the charge burden depending on the target chemical composition of the casting alloy. Of particular importance is the application of the algorithm when the process conditions are changeable.

Comparison of Energy Consumption in the Classical (PID) and Fuzzy Control of Foundry Resistance Furnace

Abstract Foundry resistance furnaces are thermal devices with a relatively large time delay in their response to a change in power parameters. Commonly used in automation classical PID controllers do not meet the requirements of high-quality control. Developed in recent years, fuzzy control theory is increasingly being used in various branches of economy and industry. Fuzzy controllers allow to introduce new developments in control systems of foundry furnaces as well. Correctly selected fuzzy controller can significantly reduce energy consumption in a controlled thermal process of heating equipment. The article presents a comparison of energy consumption by control system of foundry resistance furnace, equipped with either a PID controller or fuzzy controller optimally chosen.

Thermal operation of arc foundry furnaces

Experimental data on the temperature distribution over the lining thicknesses of the walls, roof, and bottom of a 6-t arc steel-melting furnace are processed. The time dependence of the heat flux density distribution over the lining thickness is determined, and the change in the enthalpy of the lining during a heat is found. Recommendations for the rational use of the heat accumulated by the lining during furnace downtime are given.

Lead poisoning in ancient Rome

Lead was known to the ancients from at least the 4th millennium BC, but its use increased markedly during Roman times, to the extent that it became a health hazard. Mines and foundry furnaces caused air pollution; lead was extensively used in plumbing; domestic utensils were made of lead and pewter, and lead salts were used in cosmetics, medicines and paints. As a microbicide, lead was also used to preserve food. A grape juice concentrate (sapa) commonly used as a sweetener was prepared by preference in lead containers. Although Roman writers commented on the toxicity of lead, classic chronic lead poisoning was first described only in the 7th century AD. Skeletallead content increased significantly in the Roman era, but peaked at a level only 41-47% of that of modern Europeans. The authors thus suggest that chronic lead poisoning did not contribute significantly to the fall of the Roman Empire in the West.

Heat rechperation in foundry furnaces

Heat rechperation in foundry furnaces

96/00641 Preliminary investigations combustion of pulverized coconut shell-based fuel slurries in an oil-fired foundry furnace

96/00641 Preliminary investigations combustion of pulverized coconut shell-based fuel slurries in an oil-fired foundry furnace

Preliminary investigations of combustion of pulverized coconut shell-based fuel slurries in an oil-fired foundry furnace

This paper reports the development effort of using coconut shell-based fuel slurries in an oil-fired foundry furnace. Solid fuel fines were dispersed in a liquid medium and the resultant fuel slurry was burnt like a liquid fuel. Light disel oil, furnace oil and water served as the liquid media. The solid fuels burnt were pulverized coal and pulverized coconut shell. The solid fuel was directly mixed with the liquid medium and was burnt in an oil-fired foundry furnace. No chemicals were used for the stabilization of slurries. Pulverized coal was found to settle down and was often blocking the fuel atomizer. But no such problems were encountered when pulverized coconut shell - light diesel oil and pulverized coconut shell-water slurries were burnt. Among the various slurries burnt, the pulverized coconut shell-water slurry was found to be the most appropriate slurry to be used in the oil-fired foundry furnace without any modifications to the existing furnace hardware. Preliminary results are presented.

Heat transfer analysis on metal-melting in a foundry solar furnace

l. INTRODUCTION The use of solar furnaces in foundries for melting and casting of alloys had been shown feasible and reported elaswbere[l]. In that paper, a description of the pilot furnace of 3 m aperture had been given, with a brief report on trial melting run with it. To improve the performance of the furnace with the existing reflector configuration, it was felt that the crucible, and the heat-shield have to be suitably designed to entrap and utilize maximum amount of available energy. This requires a detailed heat-transfer analysis to have an insight into the various unknown parameters, such as the quantity of heat lost from the crucible and the charge, in convection, radiation and conduction. In the available literature, no such analysis for solar melting has been reported, except an attempt made in this direction by John et a/.[2]. But their calculations for tin melting in a model solar furnace gave inaccurate results because of the wrong approach made. In this paper, we are presenting a simple, beat-transfer analysis with a model calculation for zinc melting. The use of a programmable calculator in these calculations is elucidated. The theoretical melting curve is compared with the experimental curve. A good agreement has been found, thereby proving the validity of the assumptions made and the analytical method chosen. When much accuracy is not required, this mathematical model could be used to compute the approximate melting time.

Investigating the reaction medium which predisposes the chrome-magnesite lining of a foundry furnace to wear. (in Russian) : A. M. Davidson, P. A. Polkvoi, and G. A. Rashin. Ogneupory, v. 22, no. 7, 1957, p. 306–312

Investigating the reaction medium which predisposes the chrome-magnesite lining of a foundry furnace to wear. (in Russian) : A. M. Davidson, P. A. Polkvoi, and G. A. Rashin. Ogneupory, v. 22, no. 7, 1957, p. 306–312