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EN
Successful casting demands that during pouring of the foundry mould with molten metal the mould cavity suffers no deformation. This, in turn, demands the use of binding materials that can give the base sand adequate strength. The main bonding materials are clay binders. The foundry industry uses minerals rich in clay, such as kaolinite, halloysite, hydromica, montmorillonite, polygorskite, vermiculite and allophane. Due to their binding capacity, montmorillonites are the most interesting minerals of all the plastic clay rocks. The basic clay rock containing montmorillonite, used as a common binding material for traditional foundry sand mixtures, is bentonite. The domestic demand for raw bentonite materials is almost entirely satisfied by imports from Slovakia, Turkey, Italy, Germany and the Czech Republic, in order of import size. In Poland, the bentonite deposits occur in very small quantities. The exploitation of bentonites is carried out only in the Krzeniów deposit, where they constitute a mineral accompanying basalt. Much more common are bentonite clays containing in addition to smectites also a large amount of other clay minerals. The article presents the results of studies of the physico-chemical and mechanical properties of moulding sand mixtures containing pure bentonite, pure clay or hybrid bentonites which are a bentonite-clay mixture. Melting was also carried out to determine the effect of the type of binder on the surface quality of iron castings.
EN
The foundry industry in Poland and EU member states is growing steadily. The alloys based on ferrous metals (cast steel and cast iron) largely contribute to this upward trend. Currently, foundries are facing the problem of increasing requirements, which enforce the production of castings characterized by high dimensional accuracy and surface smoothness with parallel elimination of casting defects. Castings are mostly made in moulding sand mixtures, which are also subject to more and more stringent requirements to meet the above-mentioned casting acceptance conditions. Additionally, moulding sands should ensure adequate mould stiffness to avoid the risk of dimensional deformations during the pouring of liquid metal to this mould and casting solidification. For these reasons, the production of this type of castings has been dominated by loose self-hardening sands with furfuryl resin, commonly called furan sands. In the group of self-hardening sands with synthetic resins, loose self-hardening sands with furfuryl resin enjoy the greatest popularity. What accounts for this fact is the high level of the reclamability of these sands, the possibility of obtaining castings with high dimensional accuracy, the ability to make intricate moulds and cores, the binding process taking place at ambient temperature, and low content of binder. Unfortunately, this technology also has some disadvantages, which include short lifetime of the sand mixture, harmful gases emitted from the sand, and currently also high cost of the sand mixture. The anticipated tightening of the environmental protection regulations in the EU countries, including limiting the content of free furfuryl alcohol in resins (<25% by mass) and reducing the emission of furfuryl alcohol, formaldehyde and BTEX compounds at workplaces, necessitated the development of a new generation of furfuryl resins friendly to the environment. The article compares the results of testing the strength properties of foundry moulding sands using two types of resins, i.e. the resin of a new generation synthesized by Grupa Azoty JRCh and a commercial resin used in the foundry industry. Additionally, derivatographic studies of the above mentioned sand mixtures were conducted, and the loss on ignition and the amount of gases emitted by the sand mixture were determined. Melting was also carried out to study the impact of the resin used on the surface quality of iron castings.
PL
W artykule przedstawiono ważniejsze wyniki prac badawczych rozwojowych i wdrożeniowych, zrealizowanych w ramach jednego z Projektów Celowych w wyniku współpracy pomiędzy Przedsiębiorstwem Techniczno Handlowym CERTECH w Niedomicach (producentem materiałów dla potrzeb odlewnictwa), a Instytutem Odlewnictwa w Krakowie. Celem projektu było opracowanie innowacyjnej technologii i uruchomienie produkcji "bentonitu zmodyfikowanego" przeznaczonego do wykonywania odlewów staliwnych o bardzo dobrej jakości powierzchni. Przedstawiono oraz omówiono wyniki badań dotyczących możliwości zastosowania dodatków węglowych w masie formierskiej przeznaczonej do wykonywania odlewów staliwnych, ich wpływu na jakość powierzchni odlewów, szczególnie na warstwę powierzchniową (naskórek odlewniczy), w aspekcie ewentualnego nawęglenia powierzchni odlewów. Efektem przedstawionych badań było opracowanie "bentonitu zmodyfikowanego", technologii jego wytwarzania oraz uruchomienie produkcji na skalę przemysłową.
EN
The article presents the most important results of the research, development and implementation studies carried out under one of the Target Projects as a result of cooperation between the CERTECH Technical and Commercial Enterprise at Niedomice (manufacturer of materials for foundry industry) and Foundry Research Institute in Cracow. The aim of the project was development of innovative technology and start up of the production of "modified bentonite" used in production of steel castings characterised by very high surface quality. The results of investigations regarding possible use of carbon additives to moulding sands for the manufacture of steel castings were presented and discussed, including the effect of these additives on casting surface quality, especially on casting skin in terms of its possible carburising. Studies were described, the final outcome of which was the development of "modified bentonite", the development of its manufacturing technology, and finally the start up of production.
PL
W artykule przedstawiono ważniejsze wyniki prac badawczo-rozwojowych i wdrożeniowych, zrealizowanych w ramach Projektów Celowych w latach 2006-2007, w dwóch krajowych odlewniach: Fabryce Łączników "Radom" w Radomiu oraz Odlewni MJM Jarosław Michalak w Ostrołęce. Celem projektów było opracowanie nowoczesnego, ekonomicznego oraz ekologicznego procesu produkcyjnego wykonywania odlewów. W Fabryce w Radomiu dotyczyło to odlewów łączników wykonywanych z żeliwa ciągliwego, w Odlewni MJM w Ostrołęce odlewów ze stopów aluminium (Al-Si) dla potrzeb energetyki. Opisano niektóre problemy odlewni związane z jakością produkowanych odlewów, zaproponowano optymalny sposób ich rozwiązania oraz przedstawiono wyniki badań dotyczących wprowadzonych rozwiązań, polegających na zastosowaniu w odlewniach nowego typu mas formierskich, zawierających w swoim składzie nowoczesny zamiennik odlewniczego pyłu węglowego o nazwie "kormix".
EN
The article discusses the most important results of research, development and implementation works conducted under Target Projects in years 2006-2007 at the two Polish foundries, i.e. "Radom" Fittings Factory in Radom and MJM Jarosław Michalak Foundry Shop in Ostrołęka. The aim of the projects was to develop a modern, economical and ecological process for the casting manufacture. In "Radom" Foundry the investigations were carried out on fittings and pipe connections cast from malleable iron; in MJM Foundry in Ostrołęka the examined castings were made from aluminium-silicon alloys and assigned for use by the power industry. Some problems faced by the Foundries in respect of casting quality were described, optimum solutions were searched, and the results of these searches were stated. The proposed solutions suggest using in foundry practice the moulding sands of a new type, containing in their composition the recently developed foundry coal dust substitute of the trade name "kormix".
5
Content available remote Bentonit z nośnikiem węgla błyszczącego w wilgotnych masach formierskich
PL
Przedstawiono badania wpływu zawartości nośnika węgla błyszczącego w bentonicie na jakość powierzchni odlewów żeliwnych. Stwierdzono, że udział nośnika dozowanego w odpowiednich ilościach w stosunku do bentonitu, gwarantuje uzyskanie powierzchni odlewu czystych i bez wad powierzchniowych.
EN
The studies on the effect of lustrous carbon contents on the quality of surface of cast iron castings were presented. It was confirmed that lustrous carbon carrier being supplied in the proper in to bentonite ensures the obtaining o f castings with clean and defect free surfaces.
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