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  • 1.
    Berglund, Anders
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Characterization of factors interacting in CGI machining: machinability - material microstructure - material physical properties2008Licentiate thesis, comprehensive summary (Other scientific)
    Abstract [en]

    The Swedish truck industry is forced to find new material solutions to achieve lighter engines with increased strength. Customers and new environmental regulations demand both higher specific power and more environmentally friendly trucks, and this places a rising pressure on the manufactures. This demand could be met by increasing the peak pressure in the cylinders. Consequently, a more efficient combustion is obtained and the exhaust lowered. This however exposes the engine to higher loads and material physical properties must therefore be enhanced.

    Today, alloyed gray iron is the predominantly used engine material. This material cannot meet the requirements of tomorrow’s engines. Compacted Graphite Iron has good potential to be the replacement; it opens new design opportunities with its superior strength, which can lead to smaller, more efficient engines and additional power. The question is: how will manufacturing be affected?

    The main goal of this thesis is to identify and investigate the main factors’ effect and their individual contributions on CGI machining.  When the relationship between the fundamental features; machinability, material microstructure, and material physical properties, are revealed, then the CGI material can be optimized, both regarding the manufacturing process and design requirements. The basic understanding is developed mainly through experimental analysis. No attempt has been made to optimize the material to be used as engine material in this thesis.

    The thesis demonstrates the importance of having good casting process control. It also illustrates the microstructural properties’ effects on CGI machinability, and what new aspects of machining must be taken into account, compared to gray iron.

  • 2.
    Berglund, Anders
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Criteria for Machinability Evaluation of Compacted Graphite Iron Materials: Design and Production Planning Perspective on Cylinder Block Manufacturing2011Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The Swedish truck industry is looking for new material solutions to achieve lighter engines with increased strength to meet customer demands and to fulfil the new regulations for more environmentally friendly trucks. This could be achieved by increasing the peak pressure in the cylinders. Consequently, a more efficient combustion is obtained and the exhaust lowered. This, however, exposes the engine to higher loads and material physical properties must therefore be enhanced. One material that could meet these demands is Compacted Graphite Iron (CGI). Its mechanical and physical properties make it ideal as cylinder block material, though there are drawbacks concerning its machinability as compared to other materials that are commonly used for the same purpose. Knowledge about machining of the material and its machinability is consequently inadequate.

    The main goal of this thesis is to identify and investigate the effect of the major factors and their individual contributions on CGI machining process behaviour. When the relationship between the fundamental features; machinability, material microstructure, and material physical properties, are revealed, the CGI material can be optimized, both regarding the manufacturing process and design requirements. The basic understanding of this is developed mainly through experimental analysis as, e.g., machining experiments and material characterization.

    The machining model presented in this thesis demonstrates the influence of material and process parameters on CGI machinability. It highlights machinability from both design and production planning perspectives. Another important objective of the thesis is an inverse thermo−mechanical FE model for intermittent machining of CGI. Here, experimental results obtained from a developed simulated milling method are used as input data, both to calibrate and validate the model. With these models, a deeper understanding is obtained regarding the way to achieve a stable process, which is the basis for future optimization procedures. The models can therefore be used as a foundation for the optimization of CGI component manufacturing.

  • 3.
    Berglund, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Archenti, Andreas
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Analytical Modelling of CGI Machining System Dynamic Behaviour2009In: Proceedings of The Internationl 3´rd Swedish Production Symposium / [ed] B.G. Rosén, Göteborg: The Swedish Production Academy , 2009, 348-357 p.Conference paper (Refereed)
  • 4.
    Berglund, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Grenmyr, G.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Kaminski, J.
    Analysis of compacted graphite iron machining by investigation of tool temperature and cutting force2008In: 1st International Conference on Process Machine Interactions: Hannover, Germany, 2008Conference paper (Other academic)
  • 5.
    Berglund, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Investigation of the Effect of Microstructures on CGI Machining2007Conference paper (Refereed)
    Abstract [en]

    The aim of this investigation is to evaluate the effect of microstructures on CGI machining and to compare to gray iron reference material. Special designed workpieces, to reproduce real situations, were machined in face milling. The project planning was based on factorial analysis of design of experiments. The results showed that the strongest parameter affecting tool life is the pearlite content. Furthermore it is clear that due to imprecision of manufacturing process it is difficult to obtain test specimens with homogenous microstructures and corresponding varying mechanical properties, when the specimen presents a complex geometrical form. Thin sections found in walls tend to have higher nodularity, resulting in spherical graphite. To refine the investigation of the effect of microstructures on CGI machining it would be preferred to use test specimens without holes or slots to minimise noise in the factor analysis.

  • 6.
    Berglund, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Richnau, Kerstin
    Scania CV AB, Materials Technology.
    Effect of carbide promoting elements on CGI material processing2010In: Proceedings of the CIRP 2nd International Conference Process Machine Interactions, 2010Conference paper (Refereed)
    Abstract [en]

    Due to environmental regulations, the industry uses both new and recycled material for the casting of new components. In the heavy truck industry, great effort is put into the purchasing of “good quality” recycled/scrap material to be used for casting CGI (compacted graphite iron) cylinder blocks and cylinder heads. Scrap material with a large concentration of carbide promoting elements reduces the machinability drastically due to carbides. The effect of carbide promoting elements on CGI machinability needs to be investigated in order to produce high quality engine components in an economically satisfactory way. This study presents the effect of the carbide promoting elements of chromium, manganese and molybdenum on CGI material processing. 17 unique CGI materials with different material chemical composition were studied. Material testing, milling experiments and image analysis of microstructure were performed on all materials, mapping the process machine interaction. The results show that all carbide promoting elements, but especially chromium, reduce the tool life in CGI milling. The results also illustrate the interaction between concentration of carbide promoting elements, material strength and machinability.

  • 7.
    Berglund, Anders
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Svensson, Henrik
    Swerea SWECAST AB.
    The Effect of Interlamellar Distance in Pearlite on CGI Machining2009In: ICME 2009: International Conference on Mechanical Engineering, 2009, 33-44 p.Conference paper (Refereed)
    Abstract [en]

    Swedish truck industry is investigating the possibilityfor implementing the use of Compacted Graphite Iron (CGI) in theirheavy duty diesel engines. Compared to the alloyed gray iron usedtoday, CGI has superior mechanical properties but not as goodmachinability. Another issue that needs to be addressed whenimplementing CGI is the inhomogeneous microstructure when thecast component has different section thicknesses, as in cylinderblocks. Thinner sections results in finer pearlite, in the material, withhigher strength. Therefore an investigation on its influence onmachinability was needed. This paper focuses on the effect thatinterlamellar distance in pearlite has on CGI machinability andmaterial physical properties. The effect of pearlite content andnodularity is also examined. The results showed that interlamellardistance in pearlite did not have as large effect on the materialphysical properties or machinability as pearlite content. The paperalso shows the difficulties of obtaining a homogeneousmicrostructure in inhomogeneous workpieces.

  • 8.
    Grenmyr, Gustav
    et al.
    Chalmers, Dept Mat & Mfg Technol.
    Berglund, Anders
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Kaminski, Jacek
    Chalmers, Dept Mat & Mfg Technol.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
    Analysis of Tool Wear in CGI Machining2008In: IMETI 2008: INTERNATIONAL MULTI-CONFERENCE ON ENGINEERING AND TECHNOLOGICAL INNOVATION, VOL I, PROCEEDINGS, 2008, 34-39 p.Conference paper (Refereed)
    Abstract [en]

    In this study the tool wear and wear mechanisms on coated cemented carbide inserts were investigated in turning of Compacted Graphite Iron (CGI) materials with different nodularity. Investigation of how small changes in nodularity affect the wear behaviour of inserts in CGI machining has not earlier been done. The inserts were examined in LOM, SEM and in EDX. The tool wear could on the basis of their wear appearance be classified in three different wear categories; A, B and C. In the wear category A, abrasive wear, adhesive wear and delamination wear could be seen. In the wear category B, the predominant wear mechanism was chipping. The wear appearance in wear category C indicated attrition wear and dissolution via diffusion. Classification of the wear mechanisms gave knowledge that could be used in tool design. The results showed that increasing nodularity has impact on wear at moderate and high cutting speed but not at lower cutting speed. Machining of all materials at high cutting speed, 400 m/min, led to complete degradation of the edge line. A small difference in nodularity from 5% to 20% has more significant impact on wear than from 20% to 62%. This seemed to be correlated with the difference in ultimate tensile strength between the materials.

  • 9.
    Grenmyr, Gustav
    et al.
    Chalmers University of Technology, Department of Materials and Manufacturing Technology.
    Berglund, Anders
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Kaminski, Jacek
    Chalmers, Dept Mat & Mfg Technol.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Investigation of tool wear mechanisms in CGI machining2011In: International Journal of Mechatronics and Manufacturing Systems, ISSN 1753-1039, Vol. 4, no 1, 3-18 p.Article in journal (Refereed)
    Abstract [en]

    In this study, the tool wear, including wear mechanisms on coated cemented carbide inserts were investigated in the turning of Compacted Graphite Iron (CGI) materials with varying nodularity. The results showed that increasing nodularity, in the range of 5–62%, affects wear at moderate and high cutting speeds without having the same impact at lower cutting speeds. A small difference in nodularity, in the lower range, such as an increase from 5% to 20%, has a more significant impact on wear than an increase from 20% to 62%.

  • 10.
    Grenmyr, Gustav
    et al.
    Chalmers University of Technology, Department of Materials and Manufacturing Technology.
    Berglund, Anders
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Kamiski, Jacek
    Chalmers University of Technology, Department of Materials and Manufacturing Technology.
    Nicolescu, Cornel Mihai
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Analysis of machining Compacted Graphite Iron (CGI) by join Investigation of Tool Temperature, Cutting Force and Tool Wear2008Conference paper (Refereed)
    Abstract [en]

    In this study a systematic approach for understanding the cutting process in CGI machining is be presented. Tool wear, tool temperature, measured with an IR camera,and cutting forces were investigated. CGI material properties were studied and contact zones on the inserts analysed. Quick stop tests were performed and a FEM temperature model, built on both experimental- and modelled data developed. The experimental data were used, both to calibrate and validate the temperature model. The results showed that increasing nodularity led to higher cutting forces and temperature. Increasing nodularity had impact on wear at moderate and high cutting speed but not at lower cutting speed. Classification of the wear mechanisms gave knowledge that could be used for tool design.The results demonstrate the need of complementing the IR camera temperature measurement with modelling to acquire an estimation of the temperatures in the cutting zone.

  • 11.
    Nayyar, Varun
    et al.
    Chalmers University of Technology.
    Svensson, Henrik
    Swerea SWECAST AB.
    König, Mathias
    Scania CV AB.
    Berglund, Anders
    KTH, School of Industrial Engineering and Management (ITM), Production Engineering, Machine and Process Technology.
    Nyborg, Lars
    Chalmers University of Technology.
    Investigation of microstructure and material properties for 18 different graphitic cast iron model materials with focus on Compacted Graphite Iron (CGI)2013In: International Journal of Microstructure and Materials Properties, ISSN 1741-8410, E-ISSN 1741-8429, Vol. 8, no 4/5, 262-282 p.Article in journal (Refereed)
    Abstract [en]

    The higher mechanical strength of Compacted Graphite Iron (CGI) than Flake Graphite Iron (FGI) makes it very useful material for several commercial components. The knowledge of microstructure and hence the mechanical properties and machinability is very important for the CGI to used efficiently in manufacturing. The complex geometry of cast components makes it difficult to produce adequate microstructure in the whole component.

    Adequate material properties can be achieved by having good knowledge about the correlations between the casted geometry, graphite morphology and pearlite content. In the presented paper, 18 different model materials have been analysed extensively, concerning the effect of chemical composition, solidification and cooling rate on the nodularity, pearlite content, interlamellar spacing in pearlite, hardness and mechanical properties. Later, the cutting force measurement tests were performed on some of the materials and it was found that the forces have a strong positive correlation with pearlite content and the tensile strength of the materials.

1 - 11 of 11
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