In the paper the results and analysis of corrosion tests were presented for low-alloyed cast steel in as-cast state and after heat treatment operations. Such alloys are applied for heavy loaded parts manufacturing, especially for mining industry. The corrosion test were performed in conditions of high salinity, similar to those occurring during the coal mining. The results have shown, that small changes in chemical composition and the heat treatment influence significantly the corrosion behaviour of studied low-alloyed cast steels.
The article shows results of studies of primary crystallization and wear resistance of Cr-Ni-Mo cast steel intended for work in corrosive and abrasive conditions. The studies of primary crystallization were conducted with use of TDA method and modified tester allowing measurement casting cooling time influence on the cooling and crystallization curves of studied alloys. After heat treatment of examined cast steel wear tests of the samples were conducted on pin-on-disc type device.
The results of research on stereological parameters of carbides in modified hypoeutectic chromium cast iron were shown in the paper. The effect of distance the casting heat centre of casting to the carbide phase morphology was examined. The samples for metallographic examination were taken from various locations of the model casting prepared in a special tester. This model casting was designed to simulate the solidification of heavy castings. Using the proposed methodology the relation of the distance from the model mould and the size, perimeter, length, width and the shape factor of carbides was examined. During the analysis, the values of stereological parameters of carbides changed on various sections of the model casting.
Paper presents the results of studies on primary crystallization and wear resistance of high chromium cast iron inoculated with ferrotitanium intended for work in abrasive conditions. Primary crystallization was examined with use of TDA method, wear tests of the samples were conducted using the modified pin-on-disk method.
The paper concerns the processes connected with the formation of chromium white cast iron microstructure. The influence of titanium and strontium on the alloy crystallization has been described using TDA method and EDS analysis. Conducted experiments allowed the determination of the selected additions influence on the microstructure of examined alloys. TDA analysis enabled indication of the characteristic temperatures of thermal effects for samples with strontium and titanium and the comparison of results for the reference sample without additions. The results of TDA test also included the analysis of the temperature first derivative values, which presented interesting differences as well. The scanning microscopy observation clearly indicated the difference between the effect of strontium and titanium on the alloy microstructure. The EDS analysis helped to identify the chemical composition of the evolving phases and confirmed the strontium presence in the eutectic. Experimental results allowed to draw reliable conclusions about the effect of applied additions on the crystallization and microstructure of chromium cast iron.
The ablation casting technology consists in pouring castings in single-use moulds made from the mixture of sand and watersoluble binder. After pouring the mould with liquid metal, while the casting is still solidifying, the mould destruction (washing out, erosion) takes place using a stream of cooling medium, which in this case is water. The following paper focuses on the selection of moulding sands with hydrated sodium silicate technologies for moulds devoted to the ablation casting of aluminum alloys. It has been proposed to use different types of moulding sands with a water-soluble binder, which is hydrated sodium silicate. The authors showed that the best kind of moulding sands for moulds for Al alloy casting will be moulding sands hardened with physical factors – through dehydration. The use of microwave hardened moulding sands and moulding sands made in hot-box technology has been proposed. The tests were carried out on moulding sands with different types of modified binder and various inorganic additives. The paper compares viscosity of different binders used in the research and thermal degradation of moulding sands with tested binders. The paper analyzes the influence of hardening time periods on bending strength of moulding sands with hydrated sodium silicate prepared in hot-box technology. The analysis of literature data and own research have shown that molding sand with hydrated sodium silicate hardened by dehydration is characterized by sufficient strength properties for the ablation foundry of Al alloys.
In this paper crystallization studies of low-alloyed construction cast steel were presented for different additions of chromium, nickel and molybdenum modified with vanadium and titanium. Studies were conducted using developed TDA stand, which additionally enabled evaluation of cooling rate influence on crystallization process of investigated alloys.
The essence of ablation casting technology consists in pouring castings in single-use moulds made from the mixture of sand and a watersoluble binder. After pouring the mould with liquid metal, while the casting is still solidifying, the mould destruction (washing out, erosion) takes place using a stream of cooling medium, which in this case is water. This paper focuses on the selection of moulding sands with hydrated sodium silicate for moulds used in the ablation casting. The research is based on the use of Cordis binder produced by the Hüttenes-Albertus Company. It is a new-generation inorganic binder based on hydrated sodium silicate. Its hardening takes place under the effect of high temperature. As part of the research, loose moulding mixtures based on the silica sand with different content of Cordis binder and special Anorgit additive were prepared. The reference material was sand mixture without the additive. The review of literature data and the results of own studies have shown that moulding sand with hydrated sodium silicate hardened by dehydration is characterized by sufficient strength properties to be used in the ablation casting process. Additionally, at the Foundry Research Institute in Krakow, preliminary semi-industrial tests were carried out on the use of Cordis sand technology in the manufacture of moulds for ablation casting. The possibility to use these sand mixtures has been confirmed in terms of both casting surface quality and sand reclamation.
In the paper the results and analysis of abrasive wear studies were shown for two grades of cast steels: low-alloyed cast steel applied for heavy machinery parts such as housing, covers etc. and chromium cast steels applied for kinetic nodes of pin-sleeve type. Studies were performed using the modified in Department of Foundry pin-on-disc method.