| 1. |
- Nayyar, Varun, 1981, et al.
(författare)
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An Experimental Investigation of Machinability of Graphitic Cast Iron Grades; Flake, Compacted and Spheroidal Graphite Iron in Continuous Machining Operations
- 2012
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Ingår i: Procedia CIRP. - : Elsevier BV. - 2212-8271. ; :1, s. 488-493
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Konferensbidrag (refereegranskat)abstract
- In this study the machinability of different grades of cast iron has been studied in terms of cutting temperatures, cutting forces, tool life, deformed chip thickness and contact length in different continuous machining operations. The tests performed were: external turning, boring and face turning. Pearlitic Flake Graphite Iron (FGI), Compacted Graphite Iron (CGI) and Spheroidal Graphite Iron (SGI) materials were selected for making the experiments. Later the machinability was also compared with ferritic SGI material. The cutting temperature has been measured with the help of thermocouple insisted inserts. These inserts were having 2 junctions; 0.55 and 1.2 mm away from the cutting edge on the clearance face. It has been seen that the cutting temperature on the clearance face has not shown any significant difference for different grades of cast irons. However, the tool life and the cutting forces have shown significant differences. The face turning tests were performed in both dry and wet conditions to see the importance of cutting fluids for different grades of cast iron. It has been seen that the CGI and SGI requires cutting fluid in a continuous machining operation. It has been seen that CGI and SGI require cutting fluid in a continuous machining operation. Later the wear mechanisms of different grades were also studied for dry and wet conditions in a boring operation. Both CGI and SGI have shown adhesion as a wear mechanism under dry conditions as compared to abrasive wear in wet conditions with a cutting speed of 300 m/min. The results can be input to designing a suitable insert for CGI and SGI and highlights the importance of using cutting fluids while machining CGI and SGI in a continuous turning operation.
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| 2. |
- Nayyar, Varun, 1981, et al.
(författare)
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An experimental investigation of temperature and machinability in turning of compacted graphite irons
- 2012
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Ingår i: International Journal of Materials and Product Technology. - 0268-1900. ; 43:1-4, s. 102-121
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Tidskriftsartikel (refereegranskat)abstract
- The life and the performance of an insert in metal cutting are mainlydependent on the heat that is generated in the contact zones on the tool rakeface with chips and on the flank face with the transient and machined surfaces.According to tool life standard, the wear on the flank face is usually taken as adecision for tool life. This occurs because of contact stresses, temperature andfriction between tool workpiece contacts. Hence, knowledge of temperature onthe flank face becomes important. The temperature on the flank face hasbeen measured in this work for different CGI materials having differentmicrostructure and physical properties in a turning operation. It has been seenthat there is no significant difference of flank temperature, while machiningdifferent CGI materials having hardness from (140 to 236 HBW). Fortemperature measurement, special inserts integrated with gold-platinumthermocouple on the flank face were used. It has been noticed that the materialshaving 31% resultant cutting force difference and six to eight times tool lifedifference have almost same temperature on the flank face measured atdifferent distances from the edge line of the insert.
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| 3. |
- Nayyar, Varun, 1981, et al.
(författare)
-
An experimental investigation of temperature and machinability in turning of compacted graphite irons
- 2011
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Ingår i: Int. J. Machining and Machinability of Materials.
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- The life and the performance of an insert in metal cutting are mainlydependent on the heat that is generated in the contact zones on the tool rakeface with chips and on the flank face with the transient and machined surfaces.According to tool life standard, the wear on the flank face is usually taken as adecision for tool life. This occurs because of contact stresses, temperature andfriction between tool workpiece contacts. Hence, knowledge of temperature onthe flank face becomes important. The temperature on the flank face hasbeen measured in this work for different CGI materials having differentmicrostructure and physical properties in a turning operation. It has been seenthat there is no significant difference of flank temperature, while machiningdifferent CGI materials having hardness from (140 to 236 HBW). Fortemperature measurement, special inserts integrated with gold-platinumthermocouple on the flank face were used. It has been noticed that the materialshaving 31% resultant cutting force difference and six to eight times tool lifedifference have almost same temperature on the flank face measured atdifferent distances from the edge line of the insert.
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| 4. |
- Nayyar, Varun, 1981, et al.
(författare)
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An Experimental Investigation of the Influence of Cutting Edge Geometry on the Machinability of Compacted Graphite Iron
- 2013
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Ingår i: International Journal of Manufacturing, Materials, and Mechanical Engineering. - : IGI Global. - 2156-1680 .- 2156-1672. ; 3:1, s. 1-25
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Tidskriftsartikel (refereegranskat)abstract
- Compacted graphite iron (CGI) is considered as the potential replacement of flake graphite iron (FGI) for the manufacturing of new generation high power diesel engines. Use of CGI, that have higher strength and stiffness as compared to FGI, allows engine to perform at higher peak pressure with higher fuel efficiency and lower emission rate. However, not only for its potential, CGI is of an area of interest in metal cutting research because of its poor machinability as compared to that of FGI. The higher strength of CGI causes a faster tool wear rate in continuous machining operation even in low cutting speed as compared to that for FGI. This study investigated the influence of cutting edge geometry at different cutting parameters on the machinability of CGI in terms of tool life, cutting force and surface roughness and integrity in internal turning operation under wet condition. It has been seen that the cutting edge radius has significant effect on tool life and cutting forces. The results can be used to select optimum cutting tool geometry for continuous machining of CGI.
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| 5. |
- Nayyar, Varun, 1981, et al.
(författare)
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Machinability of Compacted Graphite Iron (CGI), a Microstructural and Mechanical Properties Comparison Approach
- 2009
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Ingår i: Swedish Production Symposium 09.
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Konferensbidrag (refereegranskat)abstract
- Compacted Graphite Iron (CGI) has an important role in manufacturing of new generation engines. Better strength of CGI allows engines to perform at higher pressure and also to have better efficiency with lower emission rate. 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 know 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 Gray Cast Iron (GCI) materials has been studied in turning operation. 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 grey cast iron (GCI) for reference. The criteria used for comparison of machinability are tool life and cutting forces. When machining CGI, 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 GCI reference material, although the force value measured for GCI was comparatively higher than for some of the CGI materials.
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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. |
- Nayyar, Varun, 1981, et al.
(författare)
-
Temperature in Turning of Compacted Graphite Iron Materials having different Physical properties and Microstructure
- 2011
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Ingår i: Swedish Production Symposium.
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Konferensbidrag (refereegranskat)abstract
- The life and the performance of an insert in metal cutting are mainly dependent on theheat that is generated in the contact zone on the tool rake and on the flank face with thetransient and machined surfaces. According to tool life standard the wear on the flankface is usually taken as a decision for tool life. Hence knowledge of temperature on theflank face becomes important. The temperature on the flank face has been measured inthis work for different CGI materials having different microstructure and physical propertiesin a turning operation. It has been seen that there is no significant difference of tooltemperature noticed while machining different CGI materials having hardness from (140-236 HBW). For temperature measurement, special inserts assisted with gold-platinumthermocouple on the flank face were used. It has been noticed that the materials having31% resultant force difference and 8-6 times tool life difference have almost sametemperature on the flank face measured at different distances from the edge line of theinsert.
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| 8. |
- Tasdelen, Bulent, 1980, et al.
(författare)
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An Experimental Study to Understand the Effect of Cooling Media at Metal Cutting
- 2007
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Ingår i: Maunsrcipt Elsevier- CIRC.
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Tidskriftsartikel (refereegranskat)abstract
- Dry and Semi-Dry machining has gained interest in the last years because of the new environmental legislations and the possibility to decrease the machining cost. However, the role of cutting media such as emulsion, compressed air and Minimum Quantity Lubrication (MQL) on the chip formation has not been understood yet. The mechanical and thermodynamical conditions in the cutting zone affects the properties of work piece material under cutting and these conditions change with the application of cutting media. In this work a medium alloyed forged steel was machined with assistance of emulsion, MQL and only compressed air and the results are compared to dry machining in terms of chip colour, micro structure, white-etching band and contact area between chip and the insert rake face. It was observed that white-etching band, which is believed to be ferrite, forms both on the chip upper free side and chip back side for all conditions. In emulsion cutting, this band has finest grains and with dry cutting it has largest grains proving a slower cooling with dry cutting. Not a big difference was observed on white-etching band when MQL, compressed air and dry machining are compared. However, it was observed that cooling ability of MQL and compressed air has affected the contact area when the media was applied on rake face.
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| 9. |
- Tasdelen, Bulent, 1980, et al.
(författare)
-
An Experimental Study to Understand the Effect of Cooling Media in Metal Cutting
- 2011
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Ingår i: International Conference on Materials Science, Metal & Manufacturing (M3 2011).
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Konferensbidrag (refereegranskat)abstract
- Dry and Semi-Dry machining has gained interest in the last years because of the new environmental legislations and the possibility to decrease the machining cost. However, the role of cutting media such as emulsion, compressed air and Minimum Quantity Lubrication (MQL) on the chip formation has not been understood yet. The mechanical and thermo dynamical conditions in the cutting zone affects the properties of work piece material under cutting and these conditions change with the application of cutting media. In this work medium alloyed forged steel was machined with assistance of emulsion, MQL and only compressed air and the results were compared to dry machining in terms of chip color, micro structure, white-etching band and contact area between chip and the insert rake face. It was observed that white-etching band, which is believed to be ferrite, forms both on the chip upper free side and chip back side for all conditions. In emulsion cutting, this band has finest grains and with dry cutting it has largest grains proving a slower cooling with dry cutting. Not a big difference was observed on white-etching band when MQL, compressed air and dry machining were compared. However, it was observed that thermo-mechanical effect of air in MQL and compressed air supply has affected the contact area when the media was applied on rake face.
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| 10. |
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