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1

Comparative analysis of stability and capability of two drilling processes in the cast product using SPC tools

Knop Krzysztof

System Safety : Human - Technical Facility - Environment

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2025

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Vol. 7, iss. 1

153--171

EN

This article presents the results of comparative studies of the machining processes of holes B and C, conducted under batch production conditions at a foundry enterprise. The analyzed qualitative characteristic was the hole diameter, which is a key dimensional parameter of the tested casting product. The aim of the study was to evaluate both drilling processes using Statistical Process Control (SPC) tools to identify the superior process in terms of stability over time and quality capability. The methodology included descriptive statistics, histogram and box plot analysis, Bland-Altman agreement testing, normality verification, and Johnson-transformed control charts. Capability indices (Cp, Cpk) and target-oriented indices (Cpm, Cpmk) were calculated using the Clements percentile method to ensure reliable interpretation for non-normal data. The results confirmed that both processes were statistically stable and demonstrated very high capability, with Cp and Cpk values exceeding 2.0, thus indicating a negligible risk of producing out-of-tolerance parts. Nonetheless, important differences were observed: process B showed lower short-term variability, nearly perfect centering within the tolerance field, and stronger capability toward the lower specification limit. In contrast, Process C, although characterized by slightly higher variability, achieved closer alignment with the nominal dimension and more balanced capability across tolerance limits, as reflected in its higher Cpm and Cpmk values. These findings highlight the need to combine stability, capability, and accuracy-to-target analyses to obtain a comprehensive picture of process quality performance, especially under conditions of asymmetric specification limits and non-normal data. From a practical perspective, both processes are stable and capable, suitable for further batch production. However, Process C can be considered generally superior due to its better alignment with the nominal value and greater actual process capability, which translates into a lower risk of producing out-of-spec products.

2

The Technique of Inorganic Core Sand Shooting with Reduced Pressure in Venting System

Skrzyński M., Dańko R., Dajczer G.

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 2

98--103

EN

The publication presents a new shooting technique with reduced pressure in venting system for manufacturing foundry cores using inorganic sand mixture with Cordis binder. Traditional technologies for producing casting cores using blowing methods, despite their undeniable advantages, including the ability to produce cores in series, also come with some disadvantages. The primary drawbacks of the process involve uneven compaction structure of the cores, with denser areas primarily located under the blow holes, and under-shooting defects, which often occur in regions away from the blow hole or in increased core cross-sectional areas. In an effort to improve core quality, a concept was developed that involves incorporating a reduced pressure in the core box venting system to support the basic overpressure process. The solutions proposed in the publication with a vacuum method of filling the cavities of multi-chamber core boxes solve a number of technical problems occurring in conventional blowing technologies. It eliminates difficulties associated with evacuating the sand from the chamber to the shooting head and into technological cavity and increases the uniform distribution and initial degree of compacting of grains in the cavity. The additive role of this “underpressure” support is to enhance corebox venting by eliminating 'air cushions' in crevices and structural elements that obstruct the flow of evacuated air. The publication presents the results of studies on core manufacturing using blowing methods conducted in three variants: classic overpressure, utilizing the core box filling phenomenon by reducing pressure, and an integrated approach combining both these methods.

3

Analysis of Influence of Sand Matrix on Properties of Moulding Compounds Made with Furan Resin Intended for 3D Printing

Gruszka D. R., Dańko R., Dereń M., Wodzisz A.

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 2

17--24

EN

Binder jetting (BJ) sand printing is a 3D printing process in which a sand mould or sand core is produced from an STL file. A single layer of a sand matrix consisting of one or more grains in height of sand is applied to a worktable, and then a liquid resin or binder is applied to bond the grains together. This process is repeated until the final result matches the CAD model. The sand matrix is the main component of ceramic cores and moulds. The present study aims to demonstrate the influence of the matrix used on the properties of the resulting moulding sand. Three types of sand matrices were selected for the study. The first was a quartz matrix for 3D printing with binder jetting; this is characterised by a sharp geometry that allows for proper layering during printing. Ordinary quartz sand was also used for the study; this type of sand is usually used for the production of sand cores in the hotbox process, among other things. The shape of this sand is irregular. The last matrix to be tested was Cerabeads sand; this was selected because its spherical geometry clearly distinguishes it from the other two matrices. The matrices were analysed for their grain sizes. Scanning electron microscope images were also taken to compare the geometries and chemical compositions of the respective matrices. In presented research utilises a sand matrix for the production of self-curing compounds with furan resin dedicated for binder jetting 3D printing. The moulding masses were produced in a laboratory circulation mixer. The laboratory moulds were produced with wooden core boxes and pre-compacted by vibration. The samples from the matrix for the 3D printing were produced using the binder jetting method. The samples were produced to determine the flexural strength, tensile strength, gas permeability, hot distortion, and apparent density. It was not possible to carry out tests for the Cerabeads sand, as the obtained moulds were too brittle to perform adequate tests. Tests with the other matrices have shown that the shape and size of the matrix affect the apparent density and gas permeability.

4

Analysis of the use of agile methods, tools and techniques in foundry enterprises

Pacana Andrzej, Czerwińska Karolina

System Safety : Human - Technical Facility - Environment

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2023

|

Vol. 5, iss. 1

1--9

EN

In an increasingly volatile environment, the importance of agile management, which should be based on flexible procedures and agile strategy, is increasing. The purpose of the study was to analyze the trend of development, level of knowledge and implications with the application of agile methods, techniques in project, program and manufacturing process management tools, as well as to identify areas of activity of foundry companies in the context of increasing the efficiency of their operations through the use of agile project approach. The completed research indicated that the knowledge and variety of application of agile methods, tools and techniques is at a relatively low level within the framework of project, program and manufacturing process management in the surveyed foundries. Among the most commonly used instrumentation are: PDCA, Kanban, SCRUM, SCRUMBAN, Lean Development, DMAIC and XP. The research showed that the use of agile instrumentation in the areas of projects, programs and manufacturing process management allows work to be done in an orderly and transparent manner. Foundries that consistently use agile instrumentation produce high-quality and non-conformity-free products with short time-to-market. Future research directions will be to perform a comparative analysis of the level of knowledge and implications of agile instrumentation in foundries located in Poland and selected neighboring countries.

5

Application of the Triboelectric Method for the Ongoing Assessment of the Quality of Reclaim in Mechanical Reclaimers

Dańko R., Pietrzak A., Gruszka D.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 2

63--70

EN

The method of the ongoing assessment of the reclaim quality originating from the mechanical reclamation is described in this paper. In the process, the triboelectric system of measuring amounts of dust in the dedusting part of a reclamation device was applied. Based on the online measurements of the amounts of dust generated in the spent sand-reclamation process and the post-process determinations of the ignition losses and granular structures of the removed dust, the proper work parameters of the experimental reclaimer were selected. The allowable value of the ignition losses as well as the main fraction of the reclaimed matrix being similar to fresh sand was assumed as the main criteria of the positive assessment of the process. Within the presented investigations, a periodically operating device for rotor-mechanical reclamation was developed. The possibility of changing the intensity and time of the reclamation treatment as well as the triboelectric system of the dust-amount measuring were applied in this device. Tests were performed for the spent moulding sand with phenol-resol resin Carbophen 5692 hardened by CO2. This sand represents the moulding sand group with a less harmful influence on the surroundings for which the recovery of the quartz matrix utilising the reclamation requires stricter control of the parameters of the reclamation process and reclaim quality.

6

Zastosowanie skaningowej kalorymetrii różnicowej (DSC) w odlewnictwie

Gracz Beata

Laboratorium - Przegląd Ogólnopolski

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2021

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nr 2

26--33

PL

Skaningowa kalorymetria różnicowa (DSC) jest jedną z najczęściej stosowanych laboratoryjnych technik analizy termicznej, znajdującą również zastosowanie przemysłowe. Celem niniejszego artykułu jest przedstawienie definicji, podstaw teoretycznych oraz możliwości zastosowania skaningowej kalorymetrii różnicowej w przemyśle odlewniczym. Zaprezentowano w nim wykorzystanie DSC w analizie różnic struktury fazowej odlewów ze stopu AI-Zn-Mg, wykonanych w technologii masy bentonitowej oraz odlewaniu kokilowym.

EN

Differential scanning calorimetry (DSC) is one of the most commonly used laboratory thermal analysis techniques, also finding industrial applications. The aim of this article is to present the definition, theoretical basis and the possibility of applying differential scanning calorimetry in the foundry industry. As an example of application, this article presents the results of the DSC analysis of AI-Zn-Mg alloy cast made in two different types of casting processes (sand mold and permanent mold).

7

The Influence of Moulding Sand Type on Mechanical and Thermal Deformation

Grabarczyk A., Major-Gabryś K., Dobosz S. M., Jakubski J., Bolibruchová D., Brůna M., Pastirčák R.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

347--351

EN

Casting industry has been enriched with the processes of mechanization and automation in production. They offer both better working standards, faster and more accurate production, but also have begun to generate new opportunities for new foundry defects. This work discusses the disadvantages of processes that can occur, to a limited extend, in the technologies associated with mould assembly and during the initial stages of pouring. These defects will be described in detail in the further part of the paper and are mainly related to the quality of foundry cores, therefore the discussion of these issues will mainly concern core moulding sands. Four different types of moulding mixtures were used in the research, representing the most popular chemically bonded moulding sands used in foundry practise. The main focus of this article is the analysis of the influence of the binder type on mechanical and thermal deformation in moulding sands.

8

Selection of Hardening Technology of Moulding Sand with Hydrated Sodium Silicate Binder Devoted to Aluminum Alloys Ablation Casting

Major-Gabryś K., Hosadyna-Kondracka M., Grabarczyk A., Kamińska J.

Archives of Metallurgy and Materials

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2019

|

Vol. 64, iss. 1

359--364

EN

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.

9

Wpływ sposobu nagrzewania i grubości rdzeni pomiarowych wykonanych z oliwinowych mas formierskich z krzemianem sodu na odkształcalność badaną na urządzeniu DMA Hot-Distortion

Stachowicz M., Paduchowicz P.

Prace Instytutu Odlewnictwa

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2018

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Vol. 58, no. 4

277--293

PL

W artykule podjęto tematykę wpływu podwyższonej temperatury na oliwinowe masy formierskie i rdzeniowe ze spoiwem nieorganicznym z grupy niemodyfikowanych gatunków uwodnionego krzemianu sodu. Sporządzone w warunkach laboratoryjnych masy na osnowie piasku oliwinowego formowano w kształtki prostopadłościenne do badania przemieszczenia wolnego końca rdzenia pomiarowego w warunkach otoczenia o podwyższonej temperaturze. W celu utwardzenia, wykonane z mas oliwinowych, kształtki poddawano szybkiemu nagrzewaniu mikrofalowemu w piecu z generatorem częstotliwości fali elektromagnetycznej f = 2,45 GHz i mocy wyjściowej 1000 W, w czasie 180 s. Badania przeprowadzono na kształtkach prostopadłościennych formowanych we wnęce o wymiarach: 25,9 × G × 120,4 mm, gdzie G = 6 lub 8, lub 10 mm. Pomiary przemieszczeń wolnego końca kształtek rdzeni pomiarowych przeprowadzono na zautomatyzowanym urządzeniu laboratoryjnym DMA Hot- Distortion. W trakcie pomiarów zastosowano trzy sposoby ogrzewania powierzchni prostopadłościennych kształtek spotykanych w technice pomiarowej odkształceń H-D (Hot Distortion Test): grzanie od dołu, grzanie od dołu i od góry (Modified Hot Distortion Test) oraz ogrzewanie tylko od góry. Przemieszczenie wolnego końca kształtek prostopadłościennych, w zależności od grubości oraz sposobów ogrzewania ich powierzchni, posłużyło do wstępnej oceny zachowania utwardzonych mikrofalowo mas oliwinowych z krzemianem sodu w warunkach otoczenia o podwyższonej temperaturze.

EN

The article raises the issue of the influence of increased temperature on olivine moulding and core sands with an inorganic binder from the group of unmodified kinds of hydrated sodium silicates. Produced at laboratory conditions, moulding sands with an olivine sand matrix were formed into cuboidal specimens to test the deformation of the free measuring core end at conditions of increased temperature. In order to harden, the measuring cores made of olivine moulding sands fast microwave heating was applied to which used was a furnace with an electromagnetic wave frequency generator f = 2.45 GHz and output power of 1000 W, in the time period of 180 s. Tests were carried out on cuboidal specimens moulded in a cavity with the dimensions 25.9 × G × 120.4 mm, where G = 6 or 8 , or 10 mm. Measurements of deformation of the free specimen end of the measuring cores were conducted on an automated laboratory DMA Hot-Distortion apparatus. During the measurements three techniques were used to heat the surfaces of cuboidal specimens which are applied in the Hot Distortion Test: heating from the bottom, heating from the bottom and the top (Modified Hot Distortion Test), and heating only from the top. The deformation of the free end of cuboidal specimens, depending on the thickness and heating techniques of their surfaces, served for the initial assessment of the behaviour of microwave hardened olivine moulding sands with sodium silicate at conditions of increased temperature.

10

Thermal Utilization of the Post Reclamation Dust from Molding Sand with Furan Resin in Test Unit

Holtzer M., Dańko R., Dańko J.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

15--18

EN

Mechanical reclamation process of spent moulding sands generate large amounts dusts containing mainly rubbed spent binding agents and quartz dust. The amounts of post-reclamation dusts, depending of the reclamation system efficiency and reclaim dedusting system, can reach 5-10% in relation to the total reclaimed moulding sand. This dust due to the high content of the organic substances is a threat to the environment and therefore requires the storage on landfills specially adapted for this type of waste. On the other hand, the presence of organic substances causes that these dusts have relatively high energy values that could be used. However, at present there is no coherent, environmentally friendly concept for the management of this type of dust. The paper presents the results of tests of thermal utilization the dusts (as a source of energy) were carried out at AGH University of Science and Technology. Thermal utilization of dusts was carried out in the co-burning with carbon carriers process or in individual burning (Patent PL 227878 B1 and patent application PL - 411 902).

11

Research of Emission of Commercial Binders Used in ALPHASET Technology - Estimated Quantitative Analysis

Roczniak A., Holtzer M., Kmita A.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 1

109--114

EN

The results of investigations of three commercial binders applied in the Alphaset technology marked as: Sample E , Sample T and Sample S are presented in the hereby paper. These samples were subjected to the pyrolysis process at a temperature of 900°C (inert atmosphere, He 99.9999). The gas chromatograph coupled with the mass spectrometer and pyrolizer (Py-GC/MS) were used in the study. The identification of gases emitted during the thermal decomposition was performed on the basis of the mass spectral library. The obtained results indicate a certain diversification of emitted gases. Among the pyrolysis products the following harmful substances were identified: furfuryl alcohol, formaldehyde, phenol and also substances from the BTEX (benzene, toluene and ethylobezneze and xylenes) PAHs (Polycyclic Aromatic Hydrocarbons) and VOC groups (Volatile Organic Compounds). Therefore, from the environment protection point of view performing systematic investigations concerning the harmfulness of binders applied in the moulding and core sands technology, is essential.

12

Modified Hot Distortion Test to Investigate the Effect of the Inorganic Binder on the High-Temperature Behaviour of Physically Hardened Moulding Sands

Stachowicz M.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

45--50

EN

This study is an attempt to determine by Hot Distortion Test (HDT) the impact of physical methods of hardening inorganic binders in the moulding sands on phenomena caused by influence of thermal energy from heating elements with a temperature of 900°C +/- 10°C. Medium silica sand-based moulding mixtures were densified and then hardened using two physical methods: microwave heating at a frequency of 2.45 GHz or classical drying at a temperature of 110°C. Sodium silicate bonded sand (SSBS) with five unmodified kinds of hydrated sodium silicates subjected to two different types of hardening method were assessed in terms of their behaviour in high temperature. Thermal behaviour by means of deformation measurement was carried out with a modified Hot Distortion Test (mHDT). Due to this advanced, but unstable by appropriate standards Hot Distortion Test gives an opportunity to measure thermoplastic deformations (L) in moulding sands in many aspects, such as time of annealing. Research carried out in this way exposed differences between inorganic binders with molar module ranging from 3.4 to 2.0. It was established that deformations under the influence of high temperature last the longest in SSBS containing binders with molar module ranging from 3.4 to 2.9. Similarly, for these types of moulding sands the method of hardening the binder is found to be essential for increasing/decreasing the rate of thermoplastic deformations during the annealing of samples. The samples of SSBS made with binders with molar module from 2.5 to 2.0 are found to be excessively susceptible to thermoplastic deformation as a result of heating them in high environmental temperature presence.

13

Influence of sand base preparation on properties of chromite moulding sands with sodium silicate hardened with selected methods

Stachowicz M., Granat K., Pałyga Ł.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 1

379--383

EN

The paper presents a research on the relation between thermal preparation of chromite sand base of moulding sands containing sodium silicate, hardened with selected physical and chemical methods, and structure of the created bonding bridges. Test specimens were prepared of chromite sand - fresh or baked at 950°C for 10 or 24 hours - mixed with 0.5 wt.% of the selected non-modified inorganic binder and, after forming, were hardened with CO2 or liquid esters, dried traditionally or heated with microwaves at 2.45 GHz. It was shown on the grounds of SEM observations that the time of baking the base sand and the hardening method significantly affect structure of the bonding bridges and are correlated with mechanical properties of the moulding sands. It was found that hardening chromite-based moulding mixtures with physical methods is much more favourable than hardening with chemical methods, guaranteeing also more than ten times higher mechanical properties.

14

Effect of Temperature on Chromite-Based Moulding Sands Bonded with Sodium Silicate

Stachowicz M., Kamiński M., Granat K., Pałyga Ł.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 2

95--100

EN

In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within 100 to 1200°C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.

15

Konwersja materiałowo-technologiczna w produkcji odlewów korpusów dla gazownictwa

Asłanowicz M., Kaczmarek J., Ościłowski A., Żurawski A.

Przegląd Odlewnictwa

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2016

|

Vol. 66, nr 3-4

124--128

PL

Odlewnia Ferro-Term Sp. zo.o. w Topoli Królewskiej funkcjonuje niespełna 10 lat. Powołana została do życia, jako uzupełnienie pro¬gramu produkcyjnego realizowanego od 1989 roku przez macierzystą firmę Ferro-Term. W założeniu odlewnia miała wypełnić na rynku polskim lukę produkcyjną w segmencie jednostkowych i małoseryjnych odlewów, ze szczególnym uwzględnieniem skomplikowanych, wysokojakościowych odlewów ze stopów żelaza. Odlewnia obecnie produkuje odlewy z żeliwa szarego, sferoidalnego, staliwa w szerokiej gamie gatunków, łącznie ze stopowymi. Zastosowane technologie odlewnicze spełniają najwyższe normy UE, zarówno pod względem nowoczesności jak i ochrony środowiska. Kierownictwo odlewni dużą wagę przywiązuje do pozyskiwania zamówień od klientów z bardzo wymagających branż, tj. m. in. gazownictwa, energetyki, przemysłu maszyn drogowych itp. Jednym z przykładów takiej współpracy jest podjęcie produkcji odlewów dla łódzkiej firmy COMMON S.A., czołowego w kraju producenta gazomierzy turbinowych, rotorowych i zwężkowych, stosowanych do przesyłu gazu. Odlewy dla COMMON S.A. wymagają szczególnych własności, w tym szczególnie szczelności przy bardzo wysokim ciśnieniu, rzędu 160 bar. Korpusy gazomierzy produkowane są z żeliwa sferoidalnego, a w ostatnim czasie ze staliwa. Nowe rynki jakie zdobywa firma COMMON S.A. stawiają coraz wyższe wymagania jakościowe, których spełnienie pozwala na rywalizację z dostawcami o najwyższej renomie.

EN

Ferro-Term I.I.C. in Topola Królewska operates less than 10 years. In was set up as a supplementation of the production program realised- since 1989 by the parent house Ferro-Term. This foundry was to fill in the production gap in the segment of individual and small-series castings with specially taken into account complicated, high-quality castings of ferrous alloys. Currently, this foundry produces castings of grey and spheroidal cast iron, of cast steel of a wide grades, togęther with alloyed cast steel. The applied casting technologies meet the highest EU standards in respect of a modernity as well as the environment protection. The management attaches a lot of significance to receiving orders from customers of very demanding sectors such as the gas engineering, power engineering, road machines industry and others. One of examples of such cooperation is the castings production for the company from Łódź, COMMON S.A., the main producer of turbine, rotor and orifice gas-meters applied for gas transmissions. Castings for the COMMON Company require special properties including tightness at very high pressures, of the order of 160 bar Gas-meters bodies are produced of spheroidal cast iron and – in the last period - of cast steel. New markets won by the COMMON S.A. Company demand higher and higher quality, which meeting allows to compete with suppliers of the highest renown.

16

Effect of Temperature on Chromite-Based Moulding Sands Bonded with Sodium Silicate

Stachowicz M., Kamiński M., Granat K., Pałyga Ł.

Archives of Foundry Engineering

|

2016

|

Vol. 16, iss. 4

147--152

EN

In the paper, a research on effects of baking temperature on chromite sand base of moulding sands bonded with sodium silicate is presented. Pure chromite sand and its chromite-based moulding sand prepared with use of sodium silicate were subjected to heating within 100 to 1200 °C. After cooling-down, changes of base grains under thermal action were determined. Chromite moulding sand was prepared with use of 0.5 wt% of domestic made, unmodified sodium silicate (water-glass) grade 145. After baking at elevated temperatures, creation of rough layer was observed on grain surfaces, of both pure chromite sand and that used as base of a moulding sand. Changes of sand grains were evaluated by scanning microscopy and EDS analyses. It was found that changes on grain surfaces are of laminar nature. The observed layer is composed of iron oxide (II) that is one of main structural components of chromite sand. In order to identify changes in internal structure of chromite sand grains, polished sections were prepared of moulding sand hardened with microwaves and baked at elevated temperatures. Microscopic observations revealed changes in grains structure in form of characteristically crystallised acicular particles with limited magnesium content, intersecting at various angles. EDS analysis showed that these particles are composed mostly of chromium oxide (III) and iron oxide (II). The temperature above that the a.m. changes are observed in both chromite-based moulding sand and in pure chromite sand. The observed phenomena were linked with hardness values and mass of this sand.

17

Effect of Sand Wetting on Physically Hardened Moulding Sands Containing a Selected Inorganic Binder. Part 1

Stachowicz M., Granat K., Pałyga Ł.

Archives of Foundry Engineering

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2016

|

Vol. 16, iss. 1

73--78

EN

In the paper, an attempt was made to evaluate the effect of preliminary wetting of high-silica base during preparation of moulding sands containing a selected grade of sodium water-glass, designed for hardening by traditional drying or by electromagnetic microwaves at 2.45 GHz. In the research, some water was dosed during stirring the sandmix before adding 1.5 wt% of the binder that was unmodified sodium water-glass grade 137, characterised by high molar module within 3.2 to 3.4. Scope of the examinations included determining the effect of wetting the base on mechanical parameters like compression, bending and tensile strength, as well as on technological parameters like permeability, abrasion resistance and apparent density. The research revealed a significant positive effect of adding water to wet surfaces of high-silica base grains on mechanical properties and quality of moulding sands hardened by physical methods, in particular by microwave heating.

18

Effect of Sand Wetting on Physically Hardened Moulding Sands Containing a Selected Inorganic Binder. Part 2

Stachowicz M., Granat K., Pałyga Ł.

Archives of Foundry Engineering

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2016

|

Vol. 16, iss. 1

79--84

EN

In the paper, an attempt is made to explain the previously observed increased effectiveness of utilising hydrated sodium water-glass grade 137 after hardening moulding sands with selected physical methods. In the modified process of preparing sandmixes, during stirring components, water as a wetting additive was introduced to the sand-binder system. Presented are examination results of influence of faster microwave heating and slower traditional drying of the so-prepared moulding sands on their tensile and bending strength, calculated per weight fraction of the binder. The measurement results were confronted with SEM observations of linking bridges and with chemical analyses of grain surfaces of high-silica base. On the grounds of comprehensive evaluation of hardened moulding sands, positive effects were found of the applied physical process of binder dehydration and presence of the wetting additive. It was observed that introduction of this additive during stirring, before adding the binder, improves flowing the binder to the places where durable linking bridges are created. It was also found that the applied methods of hardening by dehydration enable creation of very durable linking bridges, strongly connected with the sand base, which results in damages of high-silica grain surfaces, when the bridges are destroyed.

19

Studies on Aluminosilicate of Palygorskites Group Used as a Binder in Green Sands System

Grabowska B., Drożyński D., Kaczmarska K., Mrówka N.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 1 spec.

31--36

EN

The possibility of application of aluminosilicate from the palygorskite (attapulgite) group as a potential substitute for bentonite in green sand system application were evaluated. The effectiveness of the application of this aluminosilicate as a binder in sand grains was determined based on the results of the determination flowability, apparent density, permeability, compacability, wear resistance and compressive, tensile and shear strength of the green sands with attapulgite participation or with a mixture of bentonite-attapulgite. The results with the properties obtained for the green sand bonded by bentonite were compared. Based on these results, it was found that attapulgite as a main binder material in the green sand does not guarantee the respective properties of moulding (e.g. it was observed low green strength properties, high apparent density of mixture, low compaction and very low wear resistance). It was recognized that the natural form of attapulgite require modification in order to obtain the appropriate properties of moulding sands, which is the subject of future work within the scope of the development application of aluminosilicate in foundry industry.

20

Prediction of Properties of Microwave-Hardened Sandmixes Containing Water-Glass with Use of Neural Networks

Stachowicz M., Pałyga Ł., Granat K.

Archives of Foundry Engineering

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2015

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Vol. 15, iss. 2

99--104

EN

Presented are results of a research on the possibility of using artificial neural networks for forecasting mechanical and technological parameters of moulding sands containing water-glass, hardened in the innovative microwave heating process. Trial predictions were confronted with experimental results of examining sandmixes prepared on the base of high-silica sand, containing various grades of sodium water-glass and additions of a wetting agent. It was found on the grounds of obtained values of tensile strength and permeability that, with use of artificial neural networks, it is possible complex forecasting mechanical and technological properties of these materials after microwave heating and the obtained data will be used in further research works on application of modern analytic methods for designing production technology of high-quality casting cores and moulds.