Wyniki wyszukiwania - Biblioteka Nauki

1

Wspomaganie diagnostyki wad odlewów narzędziami zarządzania jakością

100%

Łybacki W. , Zawadzka K.

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2008

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tom Vol. 28, nr 1

89-101

PL

Przedstawiono sposób analizy wad odlewów oparty na koncepcji ważonego diagramu Ishika-wy. Znany diagram Ishikawy, po określeniu zbioru przyczyn głównych i zbioru podprzyczyn, uzupełniono o wagi cząstkowe. Przypisanie poszczególnym przyczynom i podprzyczynom wag pozwala wyodrębnić na wykresie Ishikawy przyczyny najistotniejsze i wyeliminować mniej ważne. Na konkretnym przykładzie przedstawiono metodykę analizy wad odlewów, ilustrując kolejne kroki odpowiednimi tabelami i rysunkami.

EN

The way of casting defects analysis based on the conception of Ishikawa balanced diagram has been presented. Attributing to respective reasons and sub reasons weights allows isolating on Ishi-kawa's diagram the most important reasons and eliminating the less important ones. By way of a concrete example methodology of casting defects diagnosis has been illustrated with tables and figures.

2

Characteristics of defects present in industrial steel castings due to metal-mould reactions

100%

Kalandyk B. , Zapała R. , Rakowska A.

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2009

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tom Vol. 54, iss. 2

289-297

EN

Studies were made on surface defects formed in industrial steel castings. It has been concluded that the defects are formed due to an interaction between molten metal and moulding sand constituents. The microscopic analysis indicated strong non-homogeneity of the examined defects in respect of both structure and chemical composition. Basing on the examinations carried out under the scanning electron microscope, it was observed that within each defect two characteristic regions could be distinguished. One of them was formed of the silica sand grains, while the other contained a complex oxide phase, the chemical composition of which depended on the type of protective coating and the cast steel grade.

PL

Przeprowadzono badania wad powierzchniowych powstałych na przemysłowych odlewach staliwnych. Stwierdzono, że powstałe wady są rezultatem oddziaływania ciekłego metalu ze składnikami masy formierskiej. Przeprowadzona analiza mikroskopowa wskazuje na silną niejednorodność badanych wad pod względem budowy i składu chemicznego. Na podstawie badań przeprowadzonych z wykorzystaniem elektronowego mikroskopu skaningowego stwierdzono, że w obrębie każdej z nich można wyróżnić dwa charakterystyczne obszary. Jeden z nich tworzą ziarna piasku kwarcowego, natomiast drugi obszar stanowi złożona faza tlenkowa, której skład chemiczny zależy od rodzaju powłoki ochronnej i gatunku staliwa.

3

Zapewnienie jakości na wydziale odlewni ciśnieniowej LUMEL S.A. - analiza wad siluminowego odlewu pokrywy

75%

Mutwil J. , Michalski M. , Breitkopf-Jarowicz K. , Tomasik K.

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2006

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tom R. 6, nr 21/1

247-254

PL

Na przykładzie konkretnego detalu przedstawiono problematykę zapewnienia jakości na wydziale odlewni ciśnieniowej LUMEL S.A.. Przedstawiono wyniki badań nad przyczynami powstawania wad w odlewie ciśnieniowym pokrywy wytwarzanej z siluminu okołoeutektycznego.

EN

On example of concrete detail the problematic of quality assurance in LUMEL S.A. die casting foundry has been presented. The examination results on causes of casting defects formation in cover die-casting manufactured from quasi-eutectic silumin have been presented.

4

Zapewnienie jakości na wydziale odlewni ciśnieniowej LUMEL S.A. - analiza wad siluminowego odlewu obudowy zaworu

75%

Mutwil J. , Michalski M. , Kędzierska A. , Psikus Z.

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2006

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tom R. 6, nr 21/1

255-262

PL

Na przykładzie konkretnego detalu przedstawiono problematykę zapewnienia jakości na wydziale odlewni ciśnieniowej LUMEL S.A.. Przedstawiono wyniki badań nad przyczynami powstawania wad w odlewie ciśnieniowym obudowy zaworu wytwarzanej z siluminu okołoeutektycznego.

EN

On example of concrete detail the problematic of quality assurance in LUMEL S.A. die casting foundry has been presented. The examination results on causes of casting defects formation in valve housing die-casting manufactured from quasi-eutectic silumin have been presented.

5

Attribute-based knowledge representation in the process of defect diagnosis

75%

Górny Z. , Kluska-Nawarecka S. , Wilk-Kołodziejczyk D.

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2010

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tom Vol. 55, iss. 3

819-826

EN

The problem of casting defects diagnosis includes several distinct areas in which only the relevant global perspective allows for a satisfactory solution of the diagnostic task. One of these areas relates to knowledge about the parameters of the possible occurrence of defects. This knowledge is the more valuable, the more extensive it is, and the more numerous are the sources it has been acquired from. It should be combined into a coherent whole and given the form allowing for component processing. The paper proposes a solution in which the methods of knowledge engineering and artificial intelligence have been used. In this solution, a very important role is played by formalisms and inference algorithm design as they have a decisive impact on the effectiveness of the diagnostic process. A new solution proposed in this paper is to use attribute table as, a tool supporting the identification of defects. To this purpose the table has been developed (as on open system) in which descriptions of defects from various sources (international literature, expert’s knowledge, production data) was collected. The entire system creates a consistent methodological approach, enabling more comprehensive treatment of the diagnostic process, what should be noted as a new solution of the problem. All this results in increased efficiency and reliability of the diagnostic process.

PL

Problem diagnostyki wad wyrobów odlewniczych obejmuje kilka odrębnych dziedzin, dla których dopiero odpowiednie globalne spojrzenie pozwala na satysfakcjonujące rozwiązanie zadań diagnostycznych. Jedna z tych dziedzin dotyczy wiedzy o parametrach możliwości wystąpienia wad. Wiedza ta jest tym bardziej cenna im jest bardziej rozległa, pozyskana z wiekszej ilości źródeł. Taką wiedzę należy połączyć w spójna całość i nadać jej forme umożliwiającą przetwarzanie komponentowe. W artykule zaproponowano rozwiązanie, w którym wykorzystane zostały inżynieria wiedzy oraz metody sztucznej inteligencji. W omawianym rozwiązaniu bardzo ważną rolę odgrywaja formalizmy oraz konstrukcja algorytmu wnioskowania gdyż mają one decydujący wpływ na efektywność procesu diagnostycznego. Całość systemu tworzy spójne podejście metodyczne, umożliwiające bardziej kompleksowe traktowanie procesu diagnostycznego. Równocześnie, zastosowanie alternatywnych rozwiązań modułu określajacego przyczyny wady (logika rozmyta, LPR, logika klasyczna), pozwala na dostosowanie procedur decyzyjnych do aktualnych kompetencji użytkownika, umożliwiając działania w warunkach niepewności. Wszystko to składa się na zwiększenie efektywności i wiarygodnosci procesu diagnostycznego.

6

Discontinuities in metal composite cast materials

75%

Gawdzińska K.

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2007

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tom Vol. 7, iss. 1

65-68

EN

While examining the quality of composite alloys it is impossible to neglect defects connected with the structural continuity of these materials. This article briefly describes a mechanism of fracture formation in metal composite alloys with reinforcement saturated by a liquid alloy matrix. These defects are illustrated by metallographic study results (macroscopic and microscopic examinations were performed with a scanning electron microscope).

7

Contribute to quantitative identification of casting defects based on computer analysis of X-ray images

75%

Ignaszak Z. , Popielarski P. , Krawiec K.

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2007

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tom Vol. 7, iss. 4

89-94

EN

The forecast of structure and properties of casting is based on results of computer simulation of physical processes which are carried out during the casting processes. For the effective using of simulation system it is necessary to validate mathematica-physical models describing process of casting formation and the creation of local discontinues, witch determinate the casting properties. In the paper the proposition for quantitative validation of VP system using solidification casting defects by information sources of II group (methods of NDT) was introduced. It was named the VP/RT validation (virtual prototyping/radiographic testing validation). Nowadays identification of casting defects noticeable on X-ray images bases on comparison of X-ray image of casting with relates to the ASTM. The results of this comparison are often not conclusive because based on operator's subjective assessment. In the paper the system of quantitative identification of iron casting defects on X-ray images and classification this defects to ASTM class is presented. The methods of pattern recognition and machine learning were applied.

8

Knowledge representation of casting metal defects by means of ontology

63%

Kluska-Nawarecka S. , Smolarek-Grzyb A. , Wilk-Kołodziejczyk D. , Adrian A.

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2007

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tom Vol. 7, iss. 3

75-78

EN

The scattered nature of information requires implementation of appropriate tools and system solutions. The conception of decentralized diagnostic system of casting metal defects, in which the methods of concept classification in the form of ontology are used, has been presented in the article. Also, the general rules of ontology creation, model division into modules, the hierarchy of classes and their instances have been introduced. There has been provided an example of ontology construction for casting defects.

9

Structural causes of defects in a cast iron mill roll

63%

Krawczyk J.

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2008

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tom Vol. 8, iss. 2

93-98

EN

This paper describes an analysis of a defective microstructure of a mill roll. For this purpose, a piece of a broken roll was collected. That roll was made of mottled cast iron. Its microstructure consisted of modular graphite, transformed ledeburite and a matrix composed of bainite and martensite. Metallographic investigations were performed nearby the fracture in the roll. Observations were conducted on polished sections, first not etched, and then etched, which allowed us to trace carefully the propagation of the fracture. There was found a strict correlation between the microstructure of the roll and the progress occurring in the crack. It was ascertained that the basic reason for the damage to the roll was banded precipitations of ledeburitic cementite. In addition, cementite formed a continuous network. Another microstructure defects of that roll are also precipitations of secondary carbides on the boundaries of former grain of austenite as well as the occurrence of upper bainite in its matrix. The results obtained hereunder allow broadening the data base relative to the genesis of damages to mill rolls, which in future will permit one to design a proper microstructure of cast iron mill rolls. Proper microstructure of cast iron mill roll should be shaped at the stage of designing the chemical composition, conditions of crystallization or heat treatment if any.

10

Influence of aluminium on the formation of pinholes in cast irons

63%

Elbel T. , Hampl J. , Vladik R. , Koukal R.

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2008

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tom Vol. 8, iss. 2

27-32

EN

Purpose: This study concerns the formation of pinholes in castings by reaction between cast iron with compacted graphite and green sand mould. Methodology: Experiments were done on bar castings moulded in green bentonite mixtures without carbonaceous matters. Moulding sand moisture and aluminium content in the melt were purposely changed. Metal was melted in a 100 kg furnace by remelting the uniform charge of return material. Metal was inoculated all at once in a ladle and modified in a reaction chamber in a mould or as sandwich method in a pouring ladle. Findings: The formation of pinholes was not caused by high moisture of the mould but this defect was sensible to aluminium content in metal. In castings with high aluminium content > 0.2 % the pinholes occurred in high numbers, and namely under low and also high moistures [> 4 %]. In previous melts with aluminium contents < 0.02 % defects occurred in small range. Practical implications: Thus the conclusions known from literature about the influence of Al on pinholes occurrence in cast irons were confirmed. Oxygen activity in metal during its flowing and cooling in the mould was also measured but this quantity was not changed too in dependence on pinholes content. Morphological analyses near the defect have indicated that it is a physical type of pinholes caused by hydrogen. Originality: A number of works were aimed at explanation of causes of pinholes formation in lamellar graphite iron castings and spheroidal graphite ones. But this defect is formed in castings from compacted graphite cast iron too and the research was aimed just to this material. The contribution is in such a way an exceptional one.

11

The oolitization rate determination of bentonite moulding mixtures

63%

Miksovsky F. , Lichy P.

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2008

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tom Vol. 8, iss. 2

103-106

EN

Bentonite mixtures belong and will always belong among the most widespread sand mixtures for the "green sand" technology of castings production. This technology's essential advantage is bentonite mixtures application reversibility in the closed circulation after composition modifications and circulation losses replenishment. After the casting of a mould, the surrounding sand mixture is strained by the solidifying casting heat and bentonite degradation occurs. In case of appropriate conditions the oolitization occurs. This phenomenon is specific only for bentonite-bonded mixtures. The oolitization of opening material silica grains brings a number of negative as well as positive features with it. It is not only a technological problem but economical and ecological as well because for minimization of mixture regeneration with a help of new sand it is necessary to know bentonite mixtures quality control tools even in term of the oolitization rate. This paper deals with the description of undemanding physical method of the oolitization rate evaluation with a help of powder density assessment and its examination with actual sand mixtures which were obtained from the Czech Republic foundry plants. There are foundry plants of heavier weight castings and in one case there was an operation where bentonite mixtures regeneration was applied. Moreover, the oolitization effect on metal penetration in test castings was verified.

12

Defects in Al casting alloy in contact with Ni coat - as the Frenkla effect

63%

Grabala K. , Patejuk A.

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2007

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tom Vol. 7, iss. 2

7-10

EN

The subjects of analysis of this work are the defects occurring in the contact area of aluminium and nickel. The purpose of this work was to do a model research. The research concerns the mechanism of the occurrence of the defects in the area of contact: aluminium alloy - nickel coat. The model research describes the making of joints between the above mentioned metals in the warming temperature lower than the time of melting temperature of aluminium and the time of welding. It was affirmed that these defects appear as the result of special diffusion - presented in professional literature as the Kirkendall - Frenkla. The made analysis of results allowed to define parameters and factors of pores - appearing it defined plane shifting in the line of parting between the metals. Appearing of three zones of diffusive alloy was observed in the contact area of given (examined) metals. Observed phenomenon of the Frenkl porosity appeared in the area of the occurrence of the Al3Ni and Al3Ni + Al phases.

13

Stress models for an assessment of the impact of casting defects on static and fatigue cast material strength

63%

Piekło J. , Pysz S. , Maj M.

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2010

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tom Vol. 55, iss. 3

899-903

EN

This paper describes the possibility of using analytical and numerical models of a void-type casting defect to determine the growth of local stress in the defect environment during static and time-varying mode of loading. The value of this stress may be one of the factors deciding about the admission of casting to operation. The analysis of the proposed models was conducted on the example of a pressure valve made from the cast iron of EN GJS 400-15 grade.

PL

Niniejsza praca przedstawia możliwość zastosowania analitycznych i numerycznych modeli wady odlewniczej typu pustki do określenia lokalnego wzrostu naprężenia w jej otoczeniu w statycznym jak i zmiennym w czasie obciążeniu. Wartość tego naprężenia może być jednym z czynników decydujących o dopuszczeniu odlewu do eksploatacji. Analizę zaproponowanych modeli przeprowadzono na przykładzie odlewu zaworu ciśnieniowego wykonanego z żeliwa EN GJS 400-15.

14

Zastosowanie metod sztucznej inteligencji do klasyfikacji wad w odlewach ze stopów Al-Si-Cu

63%

Dobrzański L. A. , Krupiński M. , Sokolowski J. H.

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2006

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tom R. 6, nr 22

598-605

PL

Praca dotyczy oceny jakości elementów np. korpusów silników samochodowych ze stopów aluminium wytworzonych metodą Cosworth, przy wykorzystaniu analizy obrazów zdjęć cyfrowych uzyskanych w wyniku rentgenograficznych badań defektoskopowych tychże elementów. Uzyskane wyniki decydują o tym, czy wytworzony produkt jest odpadem poprodukcyjnym czy też nie, co ma na celu zmniejszenie liczby wytwarzanych produktów niespełniających kryteriów kontroli technicznej. W pracy przedstawiono opracowaną, komputerowo wspomaganą metodę oceny jakości odlewów, na podstawie morfologii wad, przy zastosowaniu narzędzi sztucznej inteligencji.

EN

This paper presents the analysis of automotive alloy castings of engine heads and blocks. The technological process applied for these Al-Si alloy castings, EN AC-AISi7Cu3Mg type, was Cosworth. AIso, it includes the development of the methodology of image analysis of casting defects. They were achieved by the defectoscopic X-ray analysis of AI-Si-Cu alloy elements, EN AC-AISi7Cu3Mg type. Besides, it contains both the manner of classification of casting defects by means of artificial intelligence, including neural networks and the application of the developed methodology in the form of a system of computer programmes for quality controI.

15

Effects of finishing on the surface quality of precision castings

63%

Patejuk A. , Poniatowska M.

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2007

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tom Vol. 7, iss. 1

93-96

EN

The paper presents some manufacturing problems concerning leaded brass casting using the precision casting method. It shows that the quality of the alloy depends on the intermetalic phase compounds known as hard inclusions that are formed in the alloy. The intrusions, composed mainly of iron, have also negative influence on obtaining good quality i.e. smooth surfaces of products. One of the methods to improve surface smoothness proposed by authors is to apply additional copper plating and fine polishing.

16

An establish attempt of reasons of machining splinter formation in AC44200 alloy high pressure die castings

63%

Mutwil J.

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2008

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tom Vol. 8, iss. 3

159-166

EN

A problem of splinter formation during machining the AC44200 alloy high pressure die casting has been experimental investigated. In order to establish the reason of this occurrence a set of 200 high pressure die casting of the tensile strength samples have been prepared. The tensile tests were carried out using a Zwick Z050 universal testing machine. JM-SPC program has been used for statistical analysis of test results. A large variability of tensile strength results has been found. In order to find the reason of this variability the fracture surface investigations (macrographs for all of samples and SEM micrographs for chosen samples) have been carried out. It has been establish that in all cases a significant decrease of tensile strength was caused by presence of inclusions or porosity. In lot of cases the inclusions have a form of oxide film.

17

Mechanisms and mechanics of porosity formation in ductile iron castings

63%

Perzyk M. , Witemberg-Perzyk D.

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2007

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tom Vol. 7, iss. 4

147-150

EN

Shrinkage defects in ductile iron castings can be of two basic types: shrinkage cavities associated with the liquid contraction prior to the expansion period of the iron as well as the porosity, which may appear even if the liquid shrinkage is fully compensated. In the present paper two possible mechanisms of the porosity are presented and analyzed. The first one is the Karsay's mechanism based on the secondary shrinkage concept. The second one is the mechanism acting during the expansion period of the iron, first suggested by Ohnaka and co-authors and essentially modified by the present authors. The mechanical interactions between casting and mould are determined for the both mechanisms. Their analysis leads to the conclusion, that porosity forms during expansion period of the melt. The direct cause is the negative pressure which appears in the central part of the casting due to the differences in expansion coefficients of the fast cooling surface layer and slow cooling inner region. Observations concerning feeding behavior of ductile iron castings, based on this mechanism, agree well with industrial practice. The secondary shrinkage is not only needless to induce the porosity, but the corresponding mechanism of its occurrence, proposed by Karsay, does not seem to be valid.

18

Investigation of cogs defects reason in green sand moulds

51%

Bast J. , Simon W. , Abdullah E.

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2010

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tom Vol. 55, iss. 3

749-755

EN

The parameters during the moulding process of green sand directly affect casting quality. In-sufficient compaction can result in rough casting surfaces and even breakage. Too much compaction requires more energy, can cause casting defects due to low gas permeability and break of cogs and causes more wear on the pattern and equipment. Depending on the moulding process parameters, the properties of the moulding sand and the geometry of the pattern, different regions in the mould experience different cohesion and adhesion forces resulting in varying mould properties. The effect of different moulding parameters was examined by small compaction sensors and a new measuring device for the determination of cohesion in the cog area and adhesion forces at the contour of cog pattern. By optimizing of moulding parameters it is possible to produce casting without cog breaking and high surface quality. These results allow foundry personnel to monitor, adjust and optimise the moulding process.

PL

Parametry procesu formowania z zastosowaniem mas klasycznych bezpośrednio wpływają na jakość odlewów. Niewłaściwe zagęszczenie może być przyczyną dużej chropowatości powierzchni odlewów a nawet uszkodzeń form. Zbyt duże zagęszczenie wymaga większych nakładów energetycznych i może powodować wady odlewów spowodowane małą przepuszczalnością, oberwaniem garbów (wystepów) form, a także jest przyczyną zwiększonego zużycia oprzyrządowania modelowego. W zależności od parametrów procesu formowania oraz właściwości masy formierskiej w różnych obszarach formy występują zróżnicowane wartości sił adhezji i kohezji wywołujące zmienne właściwości formy. Wpływ zróżnicowanych parametrów formowania był badany przy użyciu małych czujników zagęszczenia oraz nowego urządzenia do określenia sił kohezji w obszarze garbu formy oraz sił adhezji na powierzchni modelu odwzorowujacej wnękę. Optymalizacja parametrów formowania umożliwia eliminacje wad odlewów spowodowanych oberwaniem garbów oraz otrzymanie odlewów o wysokiej jakości powierzchni. Przedstawione wyniki umożliwiają personelowi odlewni monitorowanie, nastawianie parametrów i optymalizowanie procesu formowania.