This paper focuses on the thermal behavior of the starch-based binder (Albertine F/1 by Hüttenes-Albertus) used in foundry technology of molding sand. The analysis of the course of decomposition of the starch material under controlled heating in the temperature range of 25-1100°C was conducted. Thermal analysis methods (TG-DTG-DSC), pyrolysis gas chromatography coupled with mass spectrometry (Py-GC/MS) and diffuse reflectance spectroscopy (DRIFT) were used. The application of various methods of thermal analysis and spectroscopic methods allows to verify the binder decomposition process in relation to conditions in the form in both inert and oxidizing atmosphere. It was confirmed that the binder decomposition is a complex multistage process. The identification of CO2 formation at set temperature range indicated the progressive process of decomposition. A qualitative evaluation of pyrolysis products was carried out and the course of structural changes occurring in the presence of oxygen was determined based on thermo-analytical investigations the temperature of the beginning of binder degradation in set condition was determined. It was noticed that, significant intensification of Albertine F/1 sample decomposition with formation of more degradation products took place at temperatures above 550ºC. Aromatic hydrocarbons were identified at 1100ºC.
Recently, some major changes have occurred in the structure of the European foundry industry, such as a rapid development in the production of castings from compacted graphite iron and light alloys at the expense of limiting the production of steel castings. This created a significant gap in the production of heavy steel castings (exceeding the weight of 30 Mg) for the metallurgical, cement and energy industries. The problem is proper moulding technology for such heavy castings, whose solidification and cooling time may take even several days, exposing the moulding material to a long-term thermal and mechanical load. Owing to their technological properties, sands with organic binders (synthetic resins) are the compositions used most often in industrial practice. Their main advantages include high strength, good collapsibility and knocking out properties, as well as easy mechanical reclamation. The main disadvantage of these sands is their harmful effect on the environment, manifesting itself at various stages of the casting process, especially during mould pouring. This is why new solutions are sought for sands based on organic binders to ensure their high technological properties but at the same time less harmfulness for the environment. This paper discusses the possibility of reducing the harmful effect of sands with furfuryl binders owing to the use of resins with reduced content of free furfuryl alcohol and hardeners with reduced sulphur content. The use of alkyd binder as an alternative to furfuryl binder has also been proposed and possible application of phenol-formaldehyde resins was considered.
One of the purposes of the application of chemically modified inorganic binders is to improve knocking out properties and the related reclamability with previously used in foundry inorganic binder (water glass), which allowing the use of ecological binders for casting nonferrous metals. Good knocking out properties of the sands is directly related to the waste sands reclamability, which is a necessary condition of effective waste management. Reclamation of moulding and core sands is a fundamental and effective way to manage waste on site at the foundry, in accordance with the Environmental Guidelines. Therefore, studies of reclamation of waste moulding and core sands with new types of inorganic binders (developed within the framework of the project) were carried out. These studies allowed to determine the degree of recovery of useful, material, what the reclaimed sand is, and the degree of its use in the production process. The article presents these results of investigation. They are a part of broader research programme executed under the project POIG.01.01.02-00- 015/09 "Advanced materials and technologies".
The paper presents the results of analyzes of gases emitted during exposure to high temperature foundry molding sands, where binders are organic resins. As a research tool has been used special gas chromatograph designed to identify odorous compounds including the group of alkanes.
The investigation results of the kinetics of binding ceramic moulds, in dependence on the solid phase content in the liquid ceramic slurries being 67, 68 and 69% - respectively, made on the basis of the aqueous binding agents Ludox AM and SK. The ultrasonic method was used for assessing the kinetics of strengthening of the multilayer ceramic mould. Due to this method, it is possible to determine the ceramic mould strength at individual stages of its production. Currently self-supporting moulds, which must have the relevant strength during pouring with liquid metal, are mainly produced. A few various factors influence this mould strength. One of them is the ceramic slurry viscosity, which influences a thickness of individual layers deposited on the wax model in the investment casting technology. Depositing of layers causes increasing the total mould thickness. Therefore, it is important to determine the drying time of each deposited layer in order to prevent the mould cracking due to insufficient drying of layers and thus the weakening of the multilayer mould structure.
One of the factors that contribute to the development of foundry moulding technology is environmental protection. The related challenges are effectively satisfied by a new inorganic binder that has been designed for castings made of non-ferrous metal alloys. This article presents in a concise way the test results, showing the ecological character of the new binder at the stage of making moulds, pouring them with metal and cooling of castings, indicating the possibilities for an economic re-use of waste materials formed during practical application of this technology. The results were compared with the results obtained on the sands with organic binders. Studies were carried out under the project POIG.01.01.02-00-015/09 "Advanced materials and technologies."
In this paper the results of studies of polymeric binders on the example of the new BioCo2 binder, including the problem of its renewability, are presented. The results of structural studies (FT-IR) for the BioCo2 binder before and after crosslinking, and bending strength tests Rg u fresh and renewed cured molding sands with BioCo2 binder are discussed. The cross-linking binder and curring of moulding sand was carried out by physical agents (microwave radiation, temperature). On the basis of obtained results was shown that it is possible to restore the initial properties of the adhesive of BioCo2 binder. The initial properties of moulding sand can be achieved, after the cross-linking binders and after curing in the moulding sands with bioCo2 binder , by supplementing the moulding sand composition by the appropriate amount of water.
This paper presents the results of research which is part of studies carried out under the project POIG.01.01.02-00-015/09 "Advanced Materials and Technologies", one of the aims of which is to introduce new, environment-friendly, inorganic binders to the production of castings from non-ferrous metals. The paper presents the results of research on the management of waste moulding sands prepared according to the new technology, including their multiple reclamation and management of post-reclamation waste. Studies of multiple reclamation are a continuation of the preliminary research described earlier. The programme of the studies described in this paper also included validation of the results under industrial conditions.
Mechanization of the process of core making with the use of inorganic and organic binders is based, almost solely, on core blowing machines. Presently the core blowing machines are equipped with tools and devices that allow for application of different technologies of core making. Cold-box, hot-box and warm-air technologies require that core blowing machines shall be additionally equipped with either core-box pre-heating system or gas purging and neutralization system, or hot air purging systems. Considering the possibility of using varied, the most advantageous technologies of core making, the production of universal core blowing machines equipped with replaceable devices has been undertaken in Poland. The universal core blowing systems allow for mechanization of core making process also with the use of sand, bonded by modern, eco-friendly binder systems. The paper presents selected results-based evaluation of core blowing process showing the scope of conducted design and implementation works.
Today, about two thirds of iron alloys casting (especially for graphitizing alloys of iron) are produced into green sand systems with usually organically bonded cores. Separation of core sands from the green sand mixture is very difficult, after pouring. The core sand concentration increase due to circulation of green sand mixture in a closed circulation system. Furthermore in some foundries, core sands have been adding to green sand systems as a replacement for new sands. The goal of this contribution is: “How the green sand systems are influenced by core sands?” This effect is considered by determination of selected technological properties and degree of green sand system re-bonding. From the studies, which have been published yet, there is not consistent opinion on influence of core sand dilution on green sand system properties. In order to simulation of the effect of core sands on the technological properties of green sands, there were applied the most common used technologies of cores production, which are based on bonding with phenolic resin. Core sand concentration added to green sand system, was up to 50 %. Influence of core sand dilution on basic properties of green sand systems was determined by evaluation of basic industrial properties: moisture, green compression strength and splitting strength, wet tensile strength, mixture stability against staling and physical-chemistry properties (pH, conductivity, and loss of ignition). Ratio of active bentonite by Methylene blue test was also determined.