Wear 267 (2009) 1856–1864 Contents lists available at ScienceDirect Wear journal homepage: www.elsevier.com/locate/wear Erosive wear of hardfaced Fe–Cr–C alloys at elevated temperature C. Katsich a,∗ , E. Badisch a , Manish Roy b , G.R. Heath c , F. Franek a,d a AC 2 T research GmbH, Viktor Kaplan-Straße 2, 2700 Wiener Neustadt, Austria b Defence Metallurgical Research Laboratory, Kanchanbagh P.O., Hyderabad, 500258, India c Castolin Eutectic International, P.O. Box 360, 1001 Lausanne, Switzerland d Vienna University of Technology, Floragasse 7, 1040 Vienna, Austria article info Article history: Received 17 September 2008 Received in revised form 10 February 2009 Accepted 5 March 2009 Available online 18 March 2009 Keywords: Fe-based Hardfacing alloy Tool steel Erosion Erosion efficiency Elevated temperature abstract Many engineering components are subjected to erosive wear at elevated temperature. As erosive wear at elevated temperature is governed by the synergistic effect of erosive wear and oxidation, it is possible to modify surfaces of the components in order to achieve improved performances. In view of the above, two different types of hardfacing alloys of Fe–Cr–C were designed incorporating Nb, Mo and B to ensure improved performances at elevated temperature. In order to achieve the above objective, mild steel was hardfaced with these alloys under optimised gas metal arc welding (GMAW) condition. The microstruc- tures of the hardfaced coating was characterised with the help of optical microscopy (OM) and scanning electron microscopy (SEM). The mechanical properties of these coatings were obtained by means of micro indenter. Erosive wear of these coatings was evaluated for four different temperatures, for two different impact angles and at one impact velocity. The morphologies and the transverse sections of the worn sur- faces are examined with SEM. The erosive wear of these coatings were compared with conventional M2 tool steel. Results indicate that erosion rate of these coatings increases with increase of test temperature and impact angles. Among various coatings, Fe–Cr–C coating containing higher amount of Nb, Mo and B exhibits best erosion resistance particularly at elevated temperature. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Erosive wear at elevated temperature is an important material removal mechanism for large number of engineering components. A list of components subjected to such condition is given in Table 1 [1–3]. The material removal under such condition is governed by the synergistic effect of erosion and oxidation [4]. The synergy between erosion and oxidation, in turn, is determined by the thickness, pli- ability, morphology, adhesion characteristics and toughness of the oxide scale. The state-of-the-art of erosive wear at elevated tem- perature has been reviewed comprehensively [5]. Hardfacing is one of the methods to modify surfaces and the tribological performances without changing the bulk prop- erties of components. Important hard facing alloys are Fe–Cr–C and Fe–C–B. Recently, synthetic multiphase composite reinforced with WC are also available. In this method of surface modifica- tion, both the coating and the substrate material is melted giving rise to a good metallurgical bond between the coating and the substrate [6,7]. Rapidly solidified fine grain microstructure con- taining finely distributed hard carbide phases give rise to a surface ∗ Corresponding author. Tel.: +43 2622 8160024; fax: +43 2622 8160099. E-mail address: katsich@ac2t.at (C. Katsich). coating having excellent combination of hardness and tough- ness. Fe–Cr–C and Fe–C–B alloys are well known for their excellent performances under severe wear conditions [8,9]. Investigation of microstructure reveals that these materials have hypoeutectic, eutectic and hypereutectic microstructures [10]. When the concen- tration of C is high, a large amount of M 7 C 3 carbides is formed. For Fe–Cr–C hardfacing alloy, having hypereutectic structure, pri- mary M 23 C 6 carbides are surrounded by cubic Cr–Fe and M 23 C 6 eutectic structure. In this kind of structure lamellar eutectic resists the spreading of crack along the grain boundary. These particu- lar materials are without WC and hence are relatively cheaper. Additionally these alloys do not contain expensive Ni. It is also to be stated that these materials can be used at higher temperature [8,11,12]. The gas metal arc welding (GMAW) process is used when a good weld appearance and a high quality of the weld are required. In this process, an electric arc is formed between a flux-cored wire electrode and the base metal. A kind of inert gas or a mixture of inert gases protects the arc region from contamination. This semi- automatic or automatic process allows a high deposition rate and is appropriate for hardfacing. The main objective of the present work is to evaluate the influ- ence of temperature on erosion behaviour of two different types 0043-1648/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.wear.2009.03.004