Experimental investigations on cryo-machining of Hastelloy C-276 with tool wear characteristics
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Sådhanå (2020)45:240 https://doi.org/10.1007/s12046-020-01477-0
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Experimental investigations on cryo-machining of Hastelloy C-276 with tool wear characteristics J KESAVAN* and V SENTHILKUMAR Department of Production Engineering, National Institute of Technology, Tiruchirappalli 620 015, India e-mail: [email protected] MS received 17 November 2019; revised 6 June 2020; accepted 29 July 2020 Abstract. The super alloy exhibits great strength and fatigue behaviour when nickel (Ni) is present in major quantities. Moreover, it possesses good corrosive resistant behaviour at high temperatures. However, these alloys are very difficult to machine under normal machining conditions due to their great strength and low heat dissolution. In this work, machining was performed on Hastelloy C276 under various machining conditions (speed, feed and depth) and environments (dry and cryogenic). Liquid nitrogen was used as a coolant in the machining region. The machinability of Hastelloy C276 was investigated with machining forces, temperature, surface roughness and hardness under different cutting conditions. Turning experiments that resulted from passing LN2 drastically reduced temperature by up to 40%. Machining forces were minimal under cryogenic machining due to its effective lubrication property. Surface finish of the machined area improved by about 26% under cryogenic conditions. Both dry and cryogenic machining improved the hardness of the work material. The high cooling efficiency of LN2 improved hardness of the machined surface was about 8-15%. Chip width and side-flow of chip material were reduced under cryogenic cooling. Moreover, adhesion and abrasion wear were observed minimally in cryogenic machining compared to dry machining. But no significant difference was observed in notch wear for both types of machining. Machinability of Hastelloy C276 significantly improved when LN2 used as a cutting fluid. Keywords.
Hastelloy; superalloy; cryogenic machining; roughness; chip morphology; tool wear.
1. Introduction Currently, Ni based super alloys are used for high temperature applications due to their mechanical strength, creep resistance, wear resistance and corrosion resistance even at high temperatures. Aircraft engine components, check valves in petrochemical industries and reactors in nuclear power plants are some of the applications of Ni based super alloys. Some Ni based alloys like, Incoloy, Hastelloy and Inconel have potential to survive in critical environments that are highly influenced by temperature and corrosion [1–4]. Most engineering industry components are made by machining processes that produce a final component with the desired shape, size and quality. Machinability and surface quality of the work material depends on cutting parameters and the cutting environment of the machining process [5]. Thakur and Gangopadhyay [6] stated that cutting parameters and cutting environment of machining processes predominantly influence surface integrities of Ni
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