Hot machining of hardened steels with coated carbide inserts

Lajis, Mohd Amri and Amin, A. K. M. Nurul and Karim, A.N. Mustafizul and Che Daud, Mohd Radzi and Ginta, Turnad Lenggo (2009) Hot machining of hardened steels with coated carbide inserts. American Journal of Engineering and Applied Sceices, 2 (2). pp. 421-427. ISSN 1941-7020

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Abstract

Problem statement: The benefits of easier manufacture of hardened steel components can be substantial in terms of reduced machining costs and lead times compared to the traditional route involving machining of the annealed state followed by heat treatment, grinding/EDM and manual finishing. But machinability of hard material through conventional machining is hindered due to excessive wear of the cutting tools and differently in achieving desired quality of the machined surface. In end milling the cutting tool is not in constant operation and so undergoes a heat cycle during the intermittent cutting. This alternate heating and cooling of the inserts lead to the thermal cracks and subsequently failure of the tool. Approach: This study was conducted to investigate the effect of preheating through inductive heating mechanism in end milling (vertical milling center) of AISI D2 hardened steel (56-62 HRC) by using coated carbide tool inserts. Apart from preheating, two other machining parameters such as cutting speed and feed were varied while the depth of cut was kept constant. Results: Tool wear phenomenon and machined surface finish were found to be significantly affected by preheating temperature and other two variables. Preheating temperature of 335°C coupled with cutting speed of 40 m min-1, depth of cut of 1.0 mm and feed of 0.02 mm/tooth resulted in a noticeable reduction in tool wear rate leading to a maximum tool life 188.55 min. In addition, cutting speed of 56.57 m min-1 together with feed of 0.044 mm/tooth and depth of cut 1.0 mm at which maximum VMR (9500 mm3) was secured provides a better surface finish with minimum surface roughness 0.25 μm leaving a possibility of skipping the grinding and polishing operations for certain applications. Conclusion/Recommendation: Through the end milling of preheated AISI D2 hardened steel by using TiAlN coated carbide cutting tool it can be concluded that an overall enhanced machinability is achievable by preventing catastrophic damage of the cutting tool at higher levels of feed and cutting speed.

Item Type:	Article (Journal)
Additional Information:	2872/1013
Uncontrolled Keywords:	Hot machining, hardened steels, tool wear and surface roughness
Subjects:	T Technology > TA Engineering (General). Civil engineering (General) > TA401 Materials of engineering and construction
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Engineering Kulliyyah of Engineering > Department of Manufacturing and Materials Engineering
Depositing User:	Dr. A.K.M. Nurul Amin
Date Deposited:	18 Jul 2011 09:44
Last Modified:	27 Mar 2012 13:54
URI:	http://irep.iium.edu.my/id/eprint/1013

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