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1

The use of combined quality management instruments to analyze the causes of non-conformities in the castings of the cover of the rail vehicle bearing housing

Czerwińska Karolina, Piwowarczyk Adam

Production Engineering Archives

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2022

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Vol. 28, Iss. 3

289--294

EN

The most critical activities influencing the success of each company are continuous improvement of the quality of manufactured products and monitoring of the production process. Skillful use of available technologies and quality management tools allows for eliminating casting non-conformities and preventing their repetition in the future. The research aimed to analyze the types of defects occurring in castings, the location of their most frequent occurrence areas, and to identify the causes of defects in castings of bearing housings used in rail vehicles. The benefits of a combination of quality management tools for diagnosing material discontinuities in the analyzed castings are presented in this article.

2

The Process of Vacuum Formation in the Shrinkage Cavity at Castings Crystallization

Khrychikov V., Semenov O., Meniailo H., Aftandiliants Y., Gnyloskurenko S.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 4

79--84

EN

The formation process of one of the most common casting defects, a shrinkage depression concerned to shrinkage cavity, was studied. The methodology, device and the experimental set up were developed to study the shrinkage cavity growth. The kinetics of vacuum formation in the cavity of the spherical casting of Al-Si-Mg alloy at its solidification in the sand-and-clay form was investigated. The data were analysed taking in mind the temperature variation in the centre of crystallizing casting. The causes of the shrinkage depression in castings were clarified. It was determined that atmospheric pressure leads to the retraction and curvature of metal layer on the surface of the casting with lower strength below which the shrinkage cavity is formed. To avoid such defects it was recommended to use the external or internal chills, feeders and other known technological methods. Deep shrinkage cavities inside the castings could be removed with an air flow through a thin tubular needle of austenitic steels for medical injections.

3

The Effect of the Return Material Implementation into the Production of Silumin Casts on Technological and Economic Indicators of Production Process

Gaspar S., Majernik J., Trytek A., Podaril M., Benova Z.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 1

69--76

EN

The production of high pressure die casts also brings difficulties regarding the processing of the waste material. It is mainly formed by runners, overflows and other foundry supplements used and, in the case of machines using the cold chamber, also the remainder from this chamber. As this material is often returned to the production process, we refer to it as return material. In the production process, it is therefore essential to deal with the proportion issue of return material against primary material that can be added to the melt to maintain the required cast properties. The submitted article monitors the quality properties of the alloy, selected mechanical properties of casts and porosity depending on the proportion of the return material in the melt. At the same time, the material savings are evaluated with regards to the amount of waste and the economic burden of the foundries. To monitor the above-mentioned factors, series of casts were produced from the seven melting process variants with a variable ratio of return to the primary material. The proportion ratio of return material in the primary alloy was adjusted from 100% of the primary alloy to 100% of the return material in the melting process. It has been proven that with the increasing proportion of the return material, the chemical composition of the melt changes, the mechanical properties of the alloy decrease and the porosity of the casts increases. Based on the results of the tests and analyzes, the optimal ratio of return and primary material in the melting process has been determined. Considering the prescribed quality of the alloy and mechanical properties, concerning the economic indicator of the savings, the ratio is set at 70:30 [%] in favor of the primary material.

4

Scanning Electron Microscopy as a Tool for Castings Quality Analysis

Jezierski Jan, Dojka M., Stawarz M., Dojka R.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 1

53--61

EN

Nowadays, the best castings’ manufacturers have to meet very demanding requirements and specifications applicable to mechanical properties and other characteristics. To fulfill those requirements, more and more sophisticated methods are being used to analyze the internal quality of castings. In many cases, the commonly used Non-Destructive Methods, like X-ray or ultrasonic testing, are not enough to ensure precise and unequivocal evaluation. Especially, when the properties of the casting only slightly fail the specification and the reasons for such failures are very subtle, thus difficult to find without the modern techniques. The paper presents some aspects of such an approach with the use of Scanning Electron Microscopy (SEM) to analyze internal defects that can critically decrease the performance of castings. The paper presents the so-called bifilm defects in ductile and chromium cast iron, near-surface corrosion caused by sulfur, micro-shrinkage located under the risers, lustrous carbon precipitates, and other microstructure features. The method used to find them, the results of their analysis, and the possible causes of the defects are presented. The conclusions prove the SEM is now a powerful tool not only for scientists but it is more and more often present in the R&D departments of the foundries.

5

Some Possibilities of Using Statistical Methods While Solving Poor Quality Production

Lakomá R., Čamek L., Lichý P., Kroupová I., Radkovský F., Obzina T.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 1

18--22

EN

This paper presents an overview of a research on six practical cases that were solved in a precise casting company where parts are cast by the mean of the low-wax casting method (investment casting) in order to decrease poor quality production. The steel cast parts production technology by the lost-wax method requires the detailed work procedures observation. On the base of statistical processing data of given types of casting products, it was possible to assess the significance of each particular checking events by using the statistical hypothesis testing. The attention was focused on wax and ceramic departments. The data in technological flow were compared before and after the implementation of the change and statistical confirmative influences were assessed. The target consisted in setting such control manners in order to get the right conditions for decreasing poor quality parts. It was evidenced that the cast part defect cause correct identification and interpretation is important.

6

Methodology for Diagnosing the Causes of Die-Casting Defects, Based on Advanced Big Data Modelling

Okuniewska A., Perzyk M. A., Kozłowski J.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 4

103--109

EN

The purpose of this paper was to develop a methodology for diagnosing the causes of die-casting defects based on advanced modelling, to correctly diagnose and identify process parameters that have a significant impact on product defect generation, optimize the process parameters and rise the products’ quality, thereby improving the manufacturing process efficiency. The industrial data used for modelling came from foundry being a leading manufacturer of the high-pressure die-casting production process of aluminum cylinder blocks for the world's leading automotive brands. The paper presents some aspects related to data analytics in the era of Industry 4.0. and Smart Factory concepts. The methodology includes computation tools for advanced data analysis and modelling, such as ANOVA (analysis of variance), ANN (artificial neural networks) both applied on the Statistica platform, then gradient and evolutionary optimization methods applied in MS Excel program’s Solver add-in. The main features of the presented methodology are explained and presented in tables and illustrated with appropriate graphs. All opportunities and risks of implementing data-driven modelling systems in high-pressure die-casting processes have been considered.

7

Investigation of Particle Filtration in Aluminium Alloy

Baumann Benedict, Keßler A., Hoppach E., Wolf G., Szucki M., Hilger O.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 3

70--80

EN

The objective of this work is to gain a deeper understanding of the separation effects and particle movement during filtration of non-metallic inclusions in aluminum casting on a macroscopic level. To understand particle movement, complex simulations are performed using Flow 3D. One focus is the influence of the filter position in the casting system with regard to filtration efficiency. For this purpose, a real filter geometry is scanned with computed tomography (CT) and integrated into the simulation as an STL file. This allows the filtration processes of particles to be represented as realistically as possible. The models provide a look inside the casting system and the flow conditions before, in, and after the filter, which cannot be mapped in real casting tests. In the second part of this work, the casting models used in the simulation are replicated and cast in real casting trials. In order to gain further knowledge about filtration and particle movement, non-metallic particles are added to the melt and then separated by a filter. These particles are then detected in the filter by metallographic analysis. The numerical simulations of particle movement in an aluminum melt during filtration, give predictions in reasonable agreement with experimental measurements.

8

Evaluation of the Cause and Consequences of Defects in Cast Metal-Ceramic Composite Foams

Popielarski P., Sika R., Czarnecka-Komorowska D., Szymański P., Rogalewicz M., Gawdzińska K.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 1

81--88

EN

In this research, the quality of manufactured cast metal-ceramic foams (manufactured using blowing gas) was tested. The causes responsible for defect formation in the composite foams and their consequences were analyzed using the FMEA (Failure Mode and Effects Analysis) method, which is a useful tool for minimizing losses caused by low product quality. This method involves analytically determining correlations between the cause and consequences of potential product defects, and it takes into account the criticality factor (risk). The FMEA analysis showed that pore breaks were the most "critical defect" (with the highest number of effects on the product, the Risk Priority Number, affecting the quality of the composite foam). The second most critical defect was discontinuities in the foam frame structure. Destruction or damage to the foam structure (although very rare) deprived the composite foam of its primary function, which is to reinforce the product. The third most critical defect was non-uniform foam pore size.

9

The Effect of Metal Pouring Conditions on the Formation of Defects in the Casting

Sowa L., Skrzypczak T., Kwiatoń P.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 2

31--36

EN

The mathematical model and numerical simulations of the solidification of a cylindrical casting, which take into account the process of the mould cavity filling by liquid metal and the feeding of the casting through the conical riser during its solidification, are proposed in the paper. The interdependence of thermal and flow phenomena were taken into account because they have an essential influence on solidification process. The effect of the pouring temperature and pouring velocity of the metal on the solidification kinetics of the casting was determined. In order to obtain the casting without shrinkage defects, an appropriate selection of these parameters was tried, which is important for foundry practice. The velocity fields have been obtained from the solution of Navier-Stokes equations and continuity equation, while temperature fields from solving the equation of heat conductivity containing the convection term. In the solidification modelling the changes in thermo-physical parameters as a function of temperature were considered. The finite element method (FEM) was used to solve the problem.

10

The Comparative Analysis of the Inclusion Removal Efficiency of Different Fluxes

Máté M., Tokár M., Fegyverneki G., Gyarmati G.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 2

53--58

EN

The Comparative Analysis of the Inclusion Removal Efficiency of Different Fluxes

11

Some Possibilities of Using Statistical Methods While Solving Poor Quality Production

Lakomá R., Čamek L., Lichý P., Kroupová I., Radkovský F., Obzina T.

Archives of Foundry Engineering

|

2020

|

Vol. 20, iss. 1

18--22

EN

This paper presents an overview of a research on six practical cases that were solved in a precise casting company where parts are cast by the mean of the low-wax casting method (investment casting) in order to decrease poor quality production. The steel cast parts production technology by the lost-wax method requires the detailed work procedures observation. On the base of statistical processing data of given types of casting products, it was possible to assess the significance of each particular checking events by using the statistical hypothesis testing. The attention was focused on wax and ceramic departments. The data in technological flow were compared before and after the implementation of the change and statistical confirmative influences were assessed. The target consisted in setting such control manners in order to get the right conditions for decreasing poor quality parts. It was evidenced that the cast part defect cause correct identification and interpretation is important.

12

Open Atlas of Defects as a Supporting Knowledge Base for Cast Iron Defects Analysis

Sika R., Rogalewicz M., Kroma A., Ignaszak Z.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 1

55--60

EN

A significant development of the foundry industry contributes to the creation of high reliability and operational strength castings so that they meet specific standards in accordance with customers’ needs. This technology, however, is inseparably connected with casting defects in finished products. Cast products are subject to various defects which are considered acceptable or not, which is conditioned by the alloy chemical composition and strength characteristics, that is, generally – qualities to be agreed between the foundry and the customer. It is the latter that led the authors to research on designing a tool enabling the most reliable possible assessment of the emerging casting defects, which after proper consultations can be repaired and the casting – sold. The paper presents an original tool named the Open Atlas of Defects (OAD), developed for the last few years to support the evaluation of cast iron defects using Non-Destructive Testing (NDT) casting defects analysis tools (DCC card – Demerit Control Chart, Pareto-Lorenz analysis and ABC analysis). The OAD tool structure was presented as an integral part of the original system module for acquisition and data mining (A&DM) in conjunction with the possibilities of using selected tools for defect analysis support on the example of cast iron casting.

13

Numerical Model of Solidification Including Formation of Multiple Shrinkage Cavities

Skrzypczak T., Sowa L., Węgrzyn-Skrzypczak E.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 1

37--42

EN

Presented paper shows the mathematical and numerical approaches for modelling of binary alloy solidification solved by the Finite Element Method (FEM). The phenomenon of shrinkage cavities formation process is included in the numerical model. Multiple macroscopic cavities can be modelled within the single casting volume. Solid, liquid and gaseous phases with different material properties are taken into account during solidification process. Mathematical model uses the differential equation of heat diffusion. Modification of specific heat is used to describe the heat releasing during liquid-solid phase change. Numerical procedure of shrinkage cavities evolution is based on the recognition of non-connected liquid volumes and local shrinkage computation in the each of them. The recognition is done by the selection of sets of interconnected nodes containing liquid phase in the finite element mesh. Original computer program was developed to perform calculation process. Obtained results of temperature and shrinkage cavities distributions are presented and discussed in details.

14

Cause-effect Analysis Using A&DM System for Casting Quality Prediction

Sika R., Ignaszak Z.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 2

5--12

EN

The paper indicates the significance of the problem of foundry processes parameters stability supervision and assessment. The parameters, which can be effectively tracked and analysed using dedicated computer systems for data acquisition and exploration (Acquisition and Data Mining systems, A&D systems) were pointed out. The state of research and methods of solving production problems with the help of computational intelligence systems (Computational Intelligence, CI) were characterised. The research part shows capabilities of an original A&DM system in the aspect of selected analyses of recorded data for cast defects (effect) forecast on the example of a chosen iron foundry. Implementation tests and analyses were performed based on selected assortments for grey and nodular cast iron grades (castings with 50 kg maximum weight, casting on automatic moulding lines for disposable green sand moulds). Validation tests results, applied methods and algorithms (the original system’s operation in real production conditions) confirmed the effectiveness of the assumptions and application of the methods described. Usability, as well as benefits of using A&DM systems in foundries are measurable and lead to stabilisation of production conditions in particular sections included in the area of use of these systems, and as a result to improvement of casting quality and reduction of defect number.

15

The Influence of the Proportion of Charge from Waste Materials on the Quality of High Pressure Castings

Schlafka P., Bydałek A. W.

Archives of Foundry Engineering

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2019

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iss. 2

21--24

EN

Nowadays, the most popular production method for manufacturing high quality casts of aluminium alloys is the hot and cold chamber die casting. Die casts made of hypereutectoid silumin Silafont 36 AlSi9Mg are used for construction elements in the automotive industry. The influence of the metal input and circulating scrap proportion on porosity and mechanical properties of the cast has been examined and the results have been shown in this article. A little porosity in samples has not influenced the details strength and the addition of the circulating scrap has contributed to the growth of the maximum tensile force. Introducing 80% of the circulating scrap has caused great porosity which led to reduce the strength of the detail. The proportion of 40% of the metal input and 60% of the circulating scrap is a configuration safe for the details quality in terms of porosity and mechanical strength.

16

The Influence of Riser Shape on Feeding Effectiveness of Solidifying Casting

Sowa L., Skrzypczak T., Kwiatoń P.

Archives of Foundry Engineering

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2019

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iss. 4

91--94

EN

The mathematical model and numerical simulations of the solidification of a cylindrical shaped casting, which take into account the process of filling the mould cavity by liquid metal and feeding the casting through the riser during its solidification, are presented in the paper. Mutual dependence of thermal and flow phenomena were taken into account because have an essential influence on solidification process. The effect of the riser shape on the effectiveness of feeding of the solidifying casting was determined. In order to obtain the casting without shrinkage defects, an appropriate selection of riser shape was made, which is important for foundry practice. Numerical calculations of the solidification process of system consisting of the casting and the conical or cylindrical riser were carried out. The velocity fields have been obtained from the solution of momentum equations and continuity equation, while temperature fields from solving the equation of heat conductivity containing the convection term. Changes in thermo-physical parameters as a function of temperature were considered. The finite element method (FEM) was used to solve the problem.

17

Influence of Silica Sand on Surface Casting Quality

Beňo J., Adamusová K., Merta V., Bajer T.

Archives of Foundry Engineering

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2019

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iss. 2

5--8

EN

The current casting production of castings brings increased demands for surface and internal quality of the castings. Important factors, that influence the quality of casted components, are the materials used for the manufacture of moulds and cores. For the preparation and production of moulds and cores, in order to achieve a low level of casting defects, then it used a high quality input materials, including various types of sands, modified binders, additives, etc. However, even the most expensive raw materials are not a guarantee to achieve the quality of production. It is always necessary to choose the appropriate combination of input material together with an appropriate proposal for the way of the production, the metallurgical treatment of cast alloy, etc. The aim of this paper is to establish the basic principles for the selection of the base core mixtures components – sands to eliminate defects from the tension, specifically veining. Various silica sand, which are commonly used in foundries of Middle Europe region, were selected and tested.

18

Wpływ czynników produkcyjnych na jakość wysokociśnieniowych odlewów wykonanych ze stopów z grupy Al-Si - analiza z wykorzystaniem diagramu Ishikawy

Poloczek Ł., Kiełbus A.

Zarządzanie Przedsiębiorstwem

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2018

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Vol. 21, nr 4

2--8

EN

Production of products required by the customer quality is one of the most important issues related to the management company. So far, quality control of the product was carried out at the end of the production process. It is increasingly giving way to projects aimed at bringing about a situation in which the number of defective products will be significantly reduced. In this situation, it becomes necessary to take action to identify the causes of major importance for the final result of the production process. For this purpose they are increasingly used quality management tool. The article presents the use of Ishikawa cause-effect diagram to identify the causes of casting defects in high pressure die casting Al-Si alloys.

19

Analysis of a Castings Quality and Metalworking Technology. Treasure of the Bronze Age Axes

Garbacz-Klempka A., Kaczmarek Ł., Kwak Z., Kozana J., Piękoś M., Perek-Nowak M., Długosz P.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 3

179--285

EN

Cast axes are one of the most numerous categories of bronze products from earlier phases of the Bronze Age found in Poland. They had multiple applications since they were not only used objects such as tools or weapons but also played the prestigious and cult roles. Investigations of the selected axes from the bronze products treasure of the Bronze Age, found in the territory of Poland, are presented in the hereby paper. The holder of these findings is the State Archaeological Museum in Warsaw. Metallurgical investigations of axes with bushing were performed in respect of the casting technology and quality of obtained castings. Macroscopic observations allowed to document the remains of the gating system and to assess the range and kind of casting defects. Light microscopy revealed the microstructure character of these relicts. The chemical composition was determined by means of the X-ray fluorescence method with energy dispersion (ED-XRF) and by the scanning electron microscopy with X-ray energy dispersion analysis in micro-areas (SEM-EDS). The shape and dimensions of cores, reproducing inner parts of axes were identified on the basis of the X-ray tomography images. Studies reconstructed production technology of the mould with gating system, determined chemical composition of the applied alloys and casting structures as well as revealed the casting defects being the result of construction and usage of moulds and cores.

20

Quality evaluation of iron casting EN-GJL-200 produced on the disamatic line

Boroń K.

Acta Innovations

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2018

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no. 29

36--40

EN

This article discusses the issues concerning the quality of casting surface with a small unit weight manufactured on the Disamatic automatic casting lines in a flaskless mould with a vertical parting line. The research was conducted in manufacturing conditions in one of the casting facilities in the country. The identification of casting defects for a monthly manufacturing cycle was made and agreed that the main causes of scrap casting are defects on the raw surface: lumps of moulding sand which after removal form cavities and draws as well as defects of gas origin such as blowholes. There are also defects of form namely short runs. In the later part of the work, the research results of the properties of moulding sand were presented and casting defects were selected the occurrence of which is connected with the quality of moulding sands.