Wear behaviour of advanced multilayer coating pvd-tiaIn in dry machining of AISI D2 hardened steel
Machining hardened steel is currently receiving increasing attention as a prospective alternative to the grinding and electrical machining (EDM) which mostly accepted as traditional methods of machining materials with hardness (>45 HRC). The reason is that it offers a comparable surface finish, s...
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| Format: | Thesis |
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2013
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| Online Access: | http://eprints.uthm.edu.my/5448/ http://eprints.uthm.edu.my/5448/1/NOR_AIN_BT_JAMIL_HOSNI.pdf |
| Summary: | Machining hardened steel is currently receiving increasing attention as a prospective alternative to the grinding and electrical machining (EDM) which mostly accepted as traditional methods of machining materials with hardness (>45 HRC). The reason is that it offers a comparable surface finish, shorter cycle time, fewer process steps, lower production cost and higher flexibility. In order to demonstrate its advances, it is important for a critical hard machining processes enable to run in optimal conditions based on specified objectives and practical constraints. This study was conducted to investigate the life and wear mechanisms of the tool, machined surface integrity such as roughness, microhardness beneath the surface and white layer in end milling of AISI D2 hardened steel (58-62 HRC) in dry machining condition. Sandvik PVD-TiAlN coated carbide cutting tool was used on a vertical machining centre (VMC). The cutting conditions including cutting speed (Vc): 80-120 m/min, radial depth of cut (ae): 3-5 mm and depth of cut (ap) is kept constant at 0.5 mm. From the results, it was found that the highest acceptable value of tool life and volume of material removal was obtained at the lowest radial depth of cut of 3 mm and the lowest cutting speed of 80 m/min. This indicates that this value of radial depth of cut and cutting speed is more suitable for machining hardened steel materials. The machined surface experienced microstructure alteration and increment in microhardness on the top white layer of the machined surface. Severe microstructure alteration was observed when the tool became dull. In addition, surface roughness values obtained were within the limit (<4 μm) specified by ISO standard for machining. Thus, the investigation on relationship of tool wear performance and surface integrity in machining AISI D2 hardened steel using coated carbide tool will lead to the development of optimum range of cutting parameters which promoting maximum productivity, maximum tool life and acceptable surface integrity of the workpiece. Hence, a good understanding of the relationship between tool wear performance and surface integrity can be used as the basis of future development of tooling and workpiece respectively. Finally, the potential of cutting performances of coated carbide insert in machining AISI D2 hardened steel could be revealed and have evidences to replace expensive cutting tools such as Polycrystalline Cubic Boron Nitride (PCBN) which its price 4-5 times higher than coated carbide insert. |
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