Journal of Surface Engineered Materials and Advanced Technology, 2013, 3, 295-302 http://dx.doi.org/10.4236/jsemat.2013.34040 Published Online October 2013 (http://www.scirp.org/journal/jsemat) Experimental Investigation of the Effect of Working Parameters on Wire Offset in Wire Electrical Discharge Machining of Hadfield Manganese Steel Ashok Kumar Srivastava 1* , Surjya Kanta Pal 2 , Probir Saha 3 , Karabi Das 4 1 Centre of Excellence in Materials Science & Engineering, Department of Metallurgical Engineering, OP Jindal Institute of Technol- ogy Raigarh, Chhattisgarh, India; 2 Department of Mechanical Engineering, IIT Kharagpur, West Bengal, India; 3 Department of Me- chanical Engineering, IIT Patna, Bihar; 4 Department of Metallurgical and Materials Engineering, IIT Kharagpur, West Bengal, India. Email: * ashok.iitkgp@yahoo.co.uk Received July 25 th , 2013; revised August 20 th , 2013; accepted September 15 th , 2013 Copyright © 2013 Ashok Kumar Srivastava et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT In this study, a series of tests have been conducted in order to investigate the machinability evaluation of austenitic Hadfield manganese steel in the Wire Electrical Discharge Machine (WEDM). Experimental investigations have been carried out to relate the effect of input machining parameters such as pulse on-time (T on ), pulse off-time (T off ), wire feed (W F ), and average gap voltage (V) on the wire offset in WEDM. No analytical approach gives the exact amount of off- set required in WEDM and hence experimental study has been undertaken. In this paper, a mathematical model has been developed to model the machinability evaluation through the response surface methodology (RSM) capable of pre- dicting the response parameter as a function of T on , T off , W F and V. The samples are tested and their average prediction error has been calculated taking the average of all the individual prediction errors. The result shows that this mathema- tical model reflects the independent, quadratic and interactive effects of the various machining parameters on cutting speed in WEDM process. Keywords: Hadfield Manganese Steel; WEDM; Pulse Time; Wire Offset; Average Gap Voltage; Response Surface Methodology 1. Introduction Hadfield manganese steel, with a composition of Fe- 1.2%C-13%Mn, is a remarkable engineering alloy in that it is soft and ductile in the fully austenitic phase form. However, when deformed, it rapidly work-hardens, even though it may suffer considerable wear from non-impact abrasive conditions, and impacting or gouging deforma- tion quickly causes it to work-harden [1]. This property makes the steel very useful in applications where heavy impact and abrasion are involved, such as within a jaw crusher, impact hammer, rail-road crossing (frog), etc. [2]. Wire Electrical Discharge Machining (WEDM) is an electro thermal production process in which thin single- strand metal wire in conjunction with de-ionized water (used to conduct electricity) cuts through metal by the use of heat from electrical sparks [3]. WEDM is a widely accepted and non-traditional machining process is used to manufacture components with intricate shapes and profiles [4]. WEDM is found to be an extremely potential electrothermal process [5,6], since it can be used in ma- chining of high strength and temperature resistive (HSTR), and it is hard and difficult to machine conductive engi- neering materials with intricate shapes. WEDM is a wide- spread technique used in industry for high-precision ma- chining of all types of conductive materials such as met- als, metallic alloys, graphite, or even some ceramic ma- terials, of any hardness [4,7,8]. Wire-EDM is capable of producing a fine, precise, corrosion-resistance and wear- resistance surface [9]. WEDM uses a series of voltage pulses, usually in rectangular form, of magnitudes of up to 400 V and those of the frequencies of the order of 5 kHz - 200 kHz, applied between the electrodes, which are separated by a small gap, typically 10 - 100 microns [10]. A thin 0.05 - 0.30 mm diameter wire performs as the electrode in WEDM and the gap between the wire and work piece is flooded with deionized water, which acts as the dielectric. Material is eroded ahead of the * Corresponding author. Copyright © 2013 SciRes. JSEMAT