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Investigation of the Effect of Microstructures on CGI Machining
KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
KTH, School of Industrial Engineering and Management (ITM), Production Engineering.
2007 (English)Conference paper, Published 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.

Place, publisher, year, edition, pages
2007.
Series
Trita-IIP, ISSN 1650-1888 ; 07-06
Keyword [en]
Microstructure, CGI, face milling, machinability, mechanical properties, section effect, cutting forces, tool wear
National Category
Production Engineering, Human Work Science and Ergonomics
Identifiers
URN: urn:nbn:se:kth:diva-25918OAI: oai:DiVA.org:kth-25918DiVA: diva2:360784
Conference
Swedish Production Symposium, Gothenburg, Sweden, 2007
Note
QC 20101104Available from: 2010-11-04 Created: 2010-11-04 Last updated: 2011-11-21Bibliographically approved
In thesis
1. Characterization of factors interacting in CGI machining: machinability - material microstructure - material physical properties
Open this publication in new window or tab >>Characterization of factors interacting in CGI machining: machinability - material microstructure - material physical properties
2008 (English)Licentiate 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.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2008. ix, 43 p.
Series
Trita-IIP, ISSN 1650-1888 ; 08-11
Keyword
CGI, Compacted Graphite Iron, milling, cast iron, machinability, material microstructure, material physical properties, CGI, kompaktgrafitjärn, fräsning, gjutjärn, skärbarhet, mikrostruktur, materialegenskaper
National Category
Production Engineering, Human Work Science and Ergonomics
Identifiers
urn:nbn:se:kth:diva-9258 (URN)978-91-7415-158-9 (ISBN)
Presentation
2008-11-14, M311, Brinellsalen, Brinellvägen 68, Stockholm, 10:00 (Swedish)
Opponent
Supervisors
Projects
OPTIMA CGI
Note
QC 20101105Available from: 2008-11-07 Created: 2008-10-14 Last updated: 2011-05-19Bibliographically approved
2. Criteria for Machinability Evaluation of Compacted Graphite Iron Materials: Design and Production Planning Perspective on Cylinder Block Manufacturing
Open this publication in new window or tab >>Criteria for Machinability Evaluation of Compacted Graphite Iron Materials: Design and Production Planning Perspective on Cylinder Block Manufacturing
2011 (English)Doctoral 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.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2011. xiii, 75 p.
Series
TRITA-IIP, ISSN 1650-1888 ; 2011-10
Keyword
Metal Cutting, Compacted Graphite Iron (CGI), Machinability, Design of Experiments (DoE), Inverse Finite Element (FE) Modelling, Simulated Milling Method
National Category
Production Engineering, Human Work Science and Ergonomics
Research subject
SRA - Production
Identifiers
urn:nbn:se:kth:diva-48430 (URN)978-91-7501-159-2 (ISBN)
Public defence
2011-12-02, F3, Lindstedtsväg 26, KTH, Stockholm, 09:00 (English)
Opponent
Supervisors
Projects
MERA - OPTIMA CGIFFI - OPTIMA phase two
Funder
XPRES - Initiative for excellence in production research
Note

QC 20111121

Available from: 2011-11-21 Created: 2011-11-18 Last updated: 2017-05-23Bibliographically approved

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