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| 3. |
- Grenmyr, Gustav, 1982, et al.
(författare)
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Analysis of Tool Wear in CGI Machining
- 2008
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Ingår i: Proceedings of International Multi-Conference on Engineering and Technological Innovation, June 29th - July 2nd, 2008 – Orlando, Florida, USA. ; Volume I, s. 34-39
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Konferensbidrag (refereegranskat)
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| 4. |
- Grenmyr, Gustav, 1982, et al.
(författare)
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Investigation of tool wear mechanisms in CGI machining
- 2011
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Ingår i: International Journal of Mechatronics and Manufacturing Systems. - : Inderscience publisher. - 1753-1039 .- 1753-1047. ; 4:1, s. 3-18
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Tidskriftsartikel (refereegranskat)abstract
- 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%.
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| 5. |
- Grenmyr, Gustav, 1982
(författare)
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Investigation on the Influence of Nodularity in Machining of Compacted Graphite Iron (CGI)
- 2008
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Stringency of environmental legislation on emission rates and increasing vehicle performance requirements are pushing the automotive and heavy truck industries to find new solutions for their diesel engines. Two potential opportunities to address these challenges involve increased combustion pressure to obtain more efficient combustion or reducing the weight of the engine. Seeking a solution through the commonly used diesel engine material, gray cast iron, is not possible due to limiting mechanical properties. But Compacted Graphite Iron (CGI) is known to be a suitable material which can meet these new demands. Despite this promise, however, the use of CGI has been limited due to difficulties in its machinability. To overcome this obstacle, better performing and suitable tools is a key factor. A good way to approach this challenge is to gain an understanding of the load picture on the tool and wear mechanisms. In this study, a systematic approach is presented for understanding the cutting process when machining Compacted Graphite Iron (CGI) materials of different nodularity with coated cemented carbide inserts. Cutting forces, tool temperature and tool wear are investigated. The tool temperature was measured with an Infra Red (IR) camera and modelled according to FEM (Finite Element Method) to estimate the temperature in the cutting zone where the IR camera was unable to function. Experimental data from cutting forces, quick-stop tests (e.g. shear plane angle), contact length measurement, tensile test and the results of the IR camera measurements were used, both to calibrate and to validate the temperature model. The results showed that increasing nodularity led to higher cutting forces and temperature. Increasing nodularity had an impact on wear at moderate and high cutting speed, but not at lower cutting speed. By classifying the wear mechanisms, we gained knowledge that may be used in tool design. The results demonstrate the need for complementing the IR camera temperature measurement with modelling to get an estimate of the temperatures in the cutting zone.
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| 6. |
- Nayyar, Varun, 1981, et al.
(författare)
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Machinability of Compacted Graphite Iron (CGI) and Flake Graphite Iron (FGI) with coated carbide
- 2013
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Ingår i: International Journal of Machining and Machinability of Materials. - 1748-5711 .- 1748-572X. ; 13:1, s. 67-90
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Tidskriftsartikel (refereegranskat)abstract
- Compacted Graphite Iron (CGI) has an important role in manufacturing of new generation engines. Better strength of CGI, as compared to flake graphite iron (FGI), allows CGI engine to perform at higher peak pressure. This can give higher fuel efficiency and lower emission rate. However, the machinability of CGI is poor as compared to FGI. The machinability of CGI is an area that needs to be studied in a better way to cut the production cost of the engine. It is a well known fact that the as-cast engine block has varying microstructure and mechanical properties due to different cooling rates at different locations of such a geometrically complex component. This has highlighted the need for studying machinability as a function of microstructural and mechanical properties so that the machining process could be optimized. For this reason, machinability of 18 different types of CGI materials along with two FGI materials has been studied in turning operation. The criteria used for comparison of machinability were tool life and cutting forces. A model for relating tool life to the mechanical properties of CGI has been developed and the machinability of the different CGIs has also been compared with flake graphite iron (FGI). A model for resultant cutting force as a function of mechanical properties and cutting parameters has been developed. It has been seen that, while machining CGI and FGI, the tool life is found to decrease drastically with increase in hardness, ultimate tensile strength and pearlite content. The highest tool life is almost 6 times of the least tool life noticed out for the 18 different types of CGI. The best tool life given by CGI is still almost half of that for the FGI materials used for comparison, although the force value measured for FGI was comparatively higher than from the ferritic CGI materials.
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| 7. |
- Tasdelen, Bulent, 1980, et al.
(författare)
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MACHINING OF GRAY CAST IRONS AND COMPACTED GRAPHITE IRON
- 2007
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Ingår i: The Swedish Production Symposium 2007.
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Konferensbidrag (refereegranskat)abstract
- Abstract: The aim of this paper is to compare the machinability of gray cast iron and compactedgraphite iron (CGI), in terms of tool life and microstructure. Two gray cast irons with differentgraphite morphologies and one CGI were tested. After the tool life tests with carbide and CubicBoron Nitride (CBN) inserts, microstructural changes on the machined surfaces wasinvestigated and SEM analysis of the inserts were performed. The results show that CBNperformed much better than Carbide tools when machining gray cast irons but did not workwhen machining CGI due to high diffusional wear. The shorter and thicker graphite flakes forone of the gray cast iron caused different chip contact and wear mechanism on the inserts. Thecomparison of machinability and tool wear gave better understanding of the wear mechanism ofCGI.
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