Journal of Materials Processing Technology 212 (2012) 402–407 Contents lists available at SciVerse ScienceDirect Journal of Materials Processing Technology j o ur nal ho me p age : www.elsevier.com/locate/jmatprotec Tool steel and copper coatings by friction surfacing –A thermography study K. Prasad Rao a,∗ , A. Veera Sreenu a , H. Khalid Rafi a , M.N. Libin b , Krishnan Balasubramaniam b a Materials Joining Laboratory, Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036, India b Machine Design Section, Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai 600 036, India a r t i c l e i n f o Article history: Received 6 August 2011 Received in revised form 30 September 2011 Accepted 30 September 2011 Available online 7 October 2011 Keywords: Infrared thermography Solid state coating Thermal profile Friction surfacing a b s t r a c t Infrared thermography was used to record thermal profiles during friction surfacing. Thermal profiles for different sets of consumable rod/substrates (tool steel/steel; copper/steel and copper/copper) were recorded and analyzed. The thermal profiles showed distinct stages of plastic deformation with respect to temperature. The mechanism of bonding or no-bonding was discussed based on thermal profile data. It was found that a metallurgically bonded coating can be obtained if the flow stress of the plasticized material is comparable with the localized stress developed due to axial loading. © 2011 Elsevier B.V. All rights reserved. 1. Introduction Friction surfacing is a useful technique of depositing solid state coatings on substrates for obtaining enhanced surface properties. It involves an initial rubbing of a consumable rod against a flat sub- strate for a definite dwell time followed by a relative movement of rod and substrate (Fig. 1). Earlier studies carried out by Madhusudhan Reddy et al. (2009) and Khalid Rafi et al. (2010a,b) showed few metallic rod/substrate combinations that resulted in friction surfaced coatings while the studies carried out by Arunsankar (2010) on few other metallic combinations could not produce any successful coatings. Further, the study by Liu et al. (2008) on understanding the mechanism during friction surfacing was limited to material transfer and the bonding mechanisms of friction surfaced coatings are not yet clearly probed. It is necessary to understand the thermal phenom- ena that take place during the entire process of coating formation as it can influence the coating formation. However, measuring temperatures at the interface of rotating components will have practical difficulties if conventional methods are applied. Infrared (IR) thermography is a convenient, non-contact method for mea- surement of temperature fields for friction surfacing. The IR camera measures temperature variations based on irradi- ance of an object surface. IR camera has been used for temperature measurement in the past for different domains. Thomann and Frisk ∗ Corresponding author. Tel.: +91 44 22574760; fax: +91 44 22574752. E-mail addresses: kpr@iitm.ac.in, jyothipr@gmail.com (K. Prasad Rao). (1968) used IR camera for heat-transfer studies, Matte et al. (2009), Huang et al. (2007), Bruggemann et al. (2000), and Mathieu et al. (2006) utilized the non-contact feature of IR camera for welding and fatigue studies, Pastor et al. (2008) used it for non-destructive flaw testing, and Marinetti and Vavilov (2010) studied different aspects of corrosion using IR camera. Reported studies in open lit- erature on thermal profiles during friction surfacing process are limited (Meola and Carlomagno, 2004; Khalid Rafi et al., 2011). In this work, it is aimed to study the feasibility of obtaining surface coatings of various ferrous and non-ferrous rods on different sub- strates. It was also aimed to understand the coating mechanisms by recording thermal profiles generated at the coating/substrate interface by using infrared thermography. 2. Experimental work Consumable rod/substrate combinations studied are as follows: (a) tool steel D2 rod on steel substrate (‘D2 ′ is a tool steel grade des- ignated by AISI-SAE containing high carbon and high chromium), (b) commercially pure (CP) copper rod on steel substrate and (c) CP Cu rod on CP Cu substrate. Dimension of the substrate was 300 mm × 200 mm × 10 mm; and the consumable rod was: 15 mm diameter and 100 mm length. The range of parameters (Axial load: 2–20 kN; rod rotation speed (RPM); 100–2500 RPM; dwell time 30–80 s) used in earlier studies (Bedford et al., 2001; Sreenu, 2010), were applied for the above consumable rod/substrate combina- tions. Chisel test was carried out to find any de-bonding at the interface between coating and substrate. Chisel test gives first hand information about the coating integrity. A chisel was hammered 0924-0136/$ – see front matter © 2011 Elsevier B.V. All rights reserved. doi:10.1016/j.jmatprotec.2011.09.023