International Refereed Journal of Engineering and Science (IRJES) ISSN (Online) 2319-183X, (Print) 2319-1821 Volume 6, Issue 11 (November 2017), PP. 34-40 www.irjes.com 34 | Page The Effects of Heat Treatment on the Mechanical Properties of Camshaft Made of Ductile Cast Iron Bahadır Karaca 1 ,Mehmet ŞİMŞİR 2 1 ESTAŞ Eksantrik San. ve Tic. A.Ş. Sivas/Turkey 2 University of Cumhuriyet, Engineering Faculty, Department of Metallurgy and Materials Eng., Sivas/Turkey Corresponding Author: Bahadır Karaca1 Abstract: The aim of this study is to investigate the effects of heat austempering and induction hardening on the wear properties of GGG60 ductile cast iron for cam shaft production. For this purpose, cam shafts have been produced by sand mould casting method. For nodulizing process, Fe-Si-Mg alloy has been used and Fe-Si-Ba- Ca-Al alloy for inoculation process. The casting has been done between 1410-1420°C and the pouring time was between 11-13 sec. The casted cam shafts and tensile test samples have been austenitized at 900°C temperatures and 90 min. time under controlled furnace atmosphere. The austenitized camshafts and tensile test samples have been quenched into the molten salt bath at 360°C temperature and held 30-60-90 min’s. and then cooled in air. By this way, austempering heat treatment has been applied. After that, surface hardening process was conducted by induction hardening machine with medium frequency. Microstructure of cam shafts and tensile test samples have been examined by optical and mechanical tests (hardness and wear tests) have been performed. Results show that austempering heat treatment increases the wear resistance of cam shaft as-cast condition. Wear resistance of the cam shaft increases with increasing austempering temperature, time and induction hardening. The lowest weight loss, 0.712mg/500m, has been obtained from the induction hardened cam shaft austempering at 360°C and 90 min. time. Keywords: Camshaft, Austenitizing, Austempering, Mechanical Properties, Microstructure I. INTRODUCTION The production of camshafts used in engines, it is carried out with the casting and machining techniques. Today, camshafts are produced from gray, nodular graphite cast iron, because of many advantages, and also machining of steel. Nodular cast iron (ductile iron) is more convenient and easier in terms of production costs compared to production of machining methods. At the same time, it is %10 lighter than steels. Austempered ductile iron (ADI) compared with steel; it has low material and production cost, low density, good process ability and a high vibration damping ability. As a result of the superior properties, it has started being used in many fields and became the subject of this study [1-2]. ADI are commonly used in structural material that should be good wear resistance and tensile strength as camshaft has an important task in engine in automotive industry. These advantages make ADI attractive in industrial applications [3-4].In ADI, ausferrite (austenite+ferrite) matrix structure is formed in austempering process that differs from bainitic structure being formed in steels. Therefore, it has different mechanical properties. When the literature is reviewed, it is noted that researches on this subject have been going on [5-7]. It is known from literature, mechanical properties of ductile iron are improved after applying austempering heat treatment [8-9]. However, the effect of induction hardening process on the properties of ADI was not seen in the literature. The aim of this study is to investigate the effects of austempering and induction hardening on microstructure and wear properties of small sectioned camshaft. II. EXPERIMENTAL STUDY 2.1 Material and Method Mould sand that will be used in the camshaft casting was prepared. Melting process is conducted in induction furnaces. The chemical composition was analyzed by spectrometer and ATAS Termal Analysis equipment. Table 1 shows the chemical composition of cast iron used in camshaft production.