Identification of Gas Products from Pyrolysis Process of Waxes Used in Lost-Wax Casting Technology

Foundry waxes currently used in lost-wax casting technology are composed of paraffin, stearin, and – to a lesser extent – ceresin, polyethylene wax, and other natural and synthetic waxes. Most of these compounds are non-toxic; however, they may release aromatic hydrocarbons as a result of exposure to high temperatures. Based on a chromatographic analysis (pyrolysis gas chromatography-mass spectrometry, Py-GC/MS), the compounds that are separated from the popular wax mixtures used in foundries were evaluated (as well as the impact they may have on foundry workers). For this purpose, the three main stages of the process (wax, burnout, and pouring) were analyzed, and the appropriate test temperature was chosen (similar to the actual conditions during the process)

TG-DTG-DSC, FTIR, DRIFT and Py-GC-MS studies of thermal decomposition for poly(sodium acrylate)/dextrin (PAANa/D) – new binder BioCo3

TG-DTG-DSC, FTIR, DRIFT, and Py-GC-MS studies have been conducted to determine the effect of the thermal decompositionconditions and structure of foundry binder BioCo3 in the form of a composition poly(sodium acrylate)/dextrin(PAANa/D) on the progress of degradation in terms of processes occurring in foundry sands in contact with liquid metal.TG-DTG-DSC curves of the composition allowed us to determine the temperature range in which they do not undergodegradation, by which they do not lose their binding properties. With temperature increasing, physical and chemicalchanges occur that are related to the evaporation of solvent water (20–110°C), followed by the release of constitutionwater, and finally intermolecular dehydration (110–230°C). In this temperature range, processes that are mainly reversibletake place. Within a temperature range of 450–826°C, polymer chains are decomposed, including the decompositionof side chains. Within a temperature range of 399–663°C, polymer composition decomposition can be observed (FTIR,DRIFT), and gas products are generated from this destruction (Py-GC-MS)

Zmiany zachodzące w bentonitach odlewniczych pod wpływem temperatury : rozprawa doktorska /

Recenzenci pracy: Petr Jelínek, Jerzy Stanisław Zych.Praca doktorska. Akademia Górniczo-Hutnicza im. Stanisława Staszica (Kraków), 2012.Bibliogr. k. 119-128.Charakterystyka, budowa, struktura, właściwości montmorillonitu, zachowanie montmorillonitu pod wpływem temperatury, badania strukturalne bentonitów, zachodzących w nich przemian, spektroskopia w podczerwieni FTIR, dyfrakcyjna analiza rentgenowska XRD, spektroskopia magnetycznego rezonansu jądrowego NMR, spektrometria masowa, masy z bentonitem, dodatki do mas formierskich, zjawisko oolityzacji, odświeżanie, regeneracja, selekcja masy, wpływ na środowisko, charakterystyka badanych materiałów, określenie podstawowych właściwości, oznaczenie zawartości wilgoci w bentonitach, przygotowanie próbek do badań, laserowa analiza ziarnowa, badania powierzchniowe bentonitu, analiza ziarnowa piasku kwarcowego, badanie właściwości wiążących bentonitów odlewniczych, oznaczanie zawartości montmorillonitu w bentonicie, w masie z bentonitem, badania technologiczne mas z bentonitami, oznaczenie wskaźnika swobodnego pęcznienia, wyniki badań właściwości wiążących bentonitów odlewniczych, oznaczanie zawartości montmorillonitu w bentonicie, w masie formierskiej, oznaczenie właściwości technologicznych mas formierskich, wskaźnika swobodnego pęcznienia, badania strukturalne bentonitów z zastosowaniem nowoczesnych metod badawczych, stosowana aparatura, analiza termiczna, spektroskopia w podczerwieni FTIR, dyfrakcyjna analiza rentgenowska XRD, spektroskopia magnetycznego rezonansu jądrowego NMR, metoda jądrowego rezonansu magnetycznego, NMR, degradacja termiczna masy formierskiej z bentonitem w procesie wykonywania modelowego odlewu, eksperyment półprzemysłowy, badanie symulacyjne rozkładu pól temperatury w formie modelowej, określenie narażenia masy na działanie wysokiej tempera tury dla odlewu klina, oznaczenie zawartości montmorillonitu w masie formierskiej, określenie narażenia masy na działanie wysokiej temperatury w zależności od powierzchni kontaktu masy z odlewem, podsumowanie badań stopnia degradacji termicznej masy formierskiej z bentonitem w oparciu o eksperyment, badania symulacyjne, analiza statystyczna wyników oznaczania zawartości montmorillonit

Dependence of tensile wet strength from regeneration time and grain size of the matrix ceramic moulds

Tyt. z nagłówka.Bibliogr. s. [61].Technologia wytwarzania precyzyjnych odlewów polega na nadawaniu elementom kształtu, wymiarów i odpowiednich własności poprzez wypełnienie ciekłym metalem formy ceramicznej odtworzonej przez model wykonany z wosku, usuwany z niej metodą wytapiania. Proces wytwarzania odlewów precyzyjnych w technologii wytapianych modeli składa się z szeregu operacji technologicznych obejmujących: wykonanie modeli woskowych i ich łączenie w zespoły modelowe, przygotowanie masy ceramicznej, nanoszenie kolejnych warstw, wytopienie wosku w autoklawie, suszenie próbek w temperaturze 100 °C, wygrzewanie próbek w zakresie temperatury od 400 do 700 °C. Dotychczasowa technologia oparta była na stosowaniu mas ceramicznych, w których spoiwem był zhydrolizowany krzemian etylu. Aktualnie, ze względu na ochronę środowiska i poprawę warunków pracy, coraz częściej spoiwo z alkoholem zastępowane jest wodnym roztworem krzemionki koloidalnej. W badaniach do tworzenia warstw formy ceramicznej stosowano osnowy pochodzące ze zużytych form z odlewni precyzyjnej poddanych regeneracji oraz osnowę świeżą. Czas regeneracji wynosił odpowiednio 5 i 15 minut. Masę po regeneracji mechanicznej poddano analizie sitowej w celu określenia wielkości ziarna dL. Ziarna o wielkości 0,2; 0,4 i 0,63 mm użyto do wykonywania warstw form ceramicznych. W artykule przedstawiono wyniki badań ukierunkowanych na wyznaczeniu zależności pomiędzy wytrzymałością na rozciąganie w stanie na wilgotno i wielkością ziarna osnowy formy ceramicznej: Rm =f(dL). Badania zostały przeprowadzone na próbkach w kształcie walca o powierzchni dzielonej, na które nanoszono warstwy z wykorzystaniem osnowy pochodzącej z regeneracji, jak również ze świeżej osnowy.Production technology of nwestment casting involves transmitting the elements of shape, dimensions and properties by filling in the appropriate liquid metal ceramic forms reproduced by a model made of wax removed by melting it. The manufacturing process of inwestment casting in the lost wax technology consists of a number of technological operations: preparing of wax models and their assembling in the model units, the preparation of ceramic mixture, successive layers of debris, wax melting in an autoclave, drying the samples at 100 °C, heating the samples at temperatures ranging from 400 to 700 °C. So far, the technology was based on the use of ceramic mixture, which the bond was hydrolysed ethyl silicate. Currently, due to environmental protection and improvement of working conditions, more and more binders with alcohol is replaced with an aqueous solution of colloidal silica. In the study, to create the individual layers a ceramic form, used regenerated ceramic mixture derived from foundry and green ingredients. The regeneration time was respectively 5 and 15 minutes. Used ceramic moulds after mechanical reclamation was given to sieve analysis to determine the grain size (di). Grain sizes 0.2, 0.4 and 0.63 mm were used for the coating of ceramic moulds. The paper presents results of research aimed at the determination of the relationship between tensile wet strength and grain size of ceramic mould: Rm = f[dL). Tests were conducted on cylindrical samples, which deposited the layers of reclaimed ceramic material.Dostępny również w formie drukowanej.SŁOWA KLUCZOWE: odlewnictwo, forma ceramiczna, osnowa, temperatura. KEYWORDS: foundry, ceramic mould, matrix, temperature

EFFECT OF GRAIN SIZE OF THE RECLAIMED MATRIX CERAMIC MOULDS USED IN THE LOST WAX TECHNOLOGY ON THE STRENGTH AT HIGH TEMPERATURE

Production technology of investment casting involves transmitting the elements of shape, dimensions and properties by filling in the appropriate liquid metal ceramic forms reproduccd by a model made of wax removed by melting it. The manufacturing process of investment casting in the lost wax technology consists of a number of technological operations: preparing of wax models and their assembling in the model units, the preparation of ceramic mixture, successive layers of debris, wax melting in an autoclave, drying the samples at 100 °C, heating the samples at temperatures ranging from 400 to 700 °C. So far, the technology was based on the use of ceramic mixture, which the bond was hydrolysed ethyl silicate. Currently, due to environmental protection and improvement of working conditions, more and more binders with alcohol is replaced with an aqueous solution of colloidal silica. In the study, as the basic of individual layers a ceramic form, used regenerated ceramic mixture derived from foundry and green ingredients. Used ceramic moulds after mechanical reclamation was given to sieve analysis to determine the grain size (dL). Grain sizes 0.2, 0.4 and 0.63 mm were used for the coating of ceramic moulds. The paper presents results of research aimed at the determination of the relationship between tensile wet strength and grain size of ceramic mould: Rm =f(dL). Tests were conducted on cylindrical samples, which deposited a layer of reclaimed ceramic material

Influence of the Changes of the Structure of Foundry Bentonites on Their Binding Properties

In this paper, the effects of the examination of the structure of calcium bentonites, activated by sodium carbonate, applied in the foundry industry as a binding agent for moulding sands, subjected to the effects of high temperature, were presented. The examination was conducted with the use of the infrared spectroscopy (FTIR) and X-ray analysis (XRD). In addition, the montmorillonite contents in the bentonite sample was determined with the use of the modern, <br /> Cu(II)-TET complex method and the technological properties of moulding sands containing the examined bentonites, such as: compactability, permeability, compression strength were examined.<p>DOI: <a href="http://dx.doi.org/10.5755/j01.ms.18.1.1342">http://dx.doi.org/10.5755/j01.ms.18.1.1342</a></p

RECLAMATION OF SPEND MOULDING SANDS WITH THE CARBOPHEN 8178 RESIN

The aim of investigations was to collect the experimental data allowing the quality assessment of the reclaimed material obtained by means of the mechanical reclamation from spent sands with the Carbophen 8178 resin. The investigation program was as follows: •   making the moulding sand with the Carbophen 8178 resin and its preparation for the primary reclamation, •   carrying out the secondary reclamation of the spent sand in the experimental mechanical reclaimer, at several variable parameters (inclination, reclamation time, rotor rotational speed), •   necessary instrumental tests of the reclaimed spent sand and the analysis of the obtained reclaimed materials. Investigations were carried our for three positions of the apparatus: α = 0o, 3o, 6o. The reclamation was performed for each position at three rotational speeds of impact-abrasive elements. The reclamation process effects were checked after 5, 10, 15 and 20 minutes. The reclamation results for the average rotational speed of the rotor, being 700 rpm, are presented in the paper

Organobentonite Binder for Binding Sand Grains in Foundry Moulding Sands

A series of studies related to the production of organobentonite, i.e., bentonite-poly(acrylic acid), and its use as a matrix grain-binding material in casting moulding sand is presented. In addition, a new carbon additive in the form of shungite was introduced into the composition of the moulding sand. Selected technological and strength properties of green sand bond with the obtained organobentonite with the addition of shungite as a new lustrous carbon carrier (Rcw, Rmw, Pw, Pw, PD) were determined. The introduction of shungite as a replacement for coal dust in the hydrocarbon resin system demonstrated the achievement of an optimum moulding sand composition for practical use in casting technology. Using chromatographic techniques (Py-GC/MS, GC), the positive effect of shungite on the quantity and quality of the gaseous products generated from the moulding sand during the thermal destruction of its components was noted, thus confirming the reduced environmental footprint of the new carbon additive compared to the commonly used lustrous carbon carriers. The test casting obtained in the mould of the organobentonite moulding sand and the shungite/hydrocarbon resin mixture showed a significantly better accuracy of the stepped model shape reproduction and surface smoothness compared to the casting obtained with the model moulding sand

The Influence of 3D Printing Core Construction (Binder Jetting) on the Amount of Generated Gases in the Environmental and Technological Aspect

This article presents the findings of a study focusing on the gas generation of 3D-printed cores fabricated using binder-jetting technology with furfuryl resin. The research aimed to compare gas emission levels, where the volume generated during the thermal degradation of the binder significantly impacts the propensity for gaseous defects in foundries. The study also investigated the influence of the binder type (conventional vs. 3D-printed dedicated binder) and core construction (shell core) on the quantity of gaseous products from the BTEX group formed during the pouring of liquid foundry metal into the cores. The results revealed that the emitted gas volume during the thermal decomposition of the organic binder depended on the core sand components and binder type. Cores produced using conventional methods emitted the least gases due to lower binder content. Increasing Kaltharz U404 resin to 1.5 parts by weight resulted in a 37% rise in gas volume and 27% higher benzene emission. Adopting shell cores reduced gas volume by over 20% (retaining sand with hardener) and 30% (removing sand with hardener), presenting an eco-friendly solution with reduced benzene emissions and core production costs. Shell cores facilitated the quicker removal of gaseous binder decomposition products, reducing the likelihood of casting defects. The disparity in benzene emissions between 3D-printed and vibratory-mixed solid cores is attributed to the sample preparation process, wherein 3D printing ensured greater uniformity