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Vadiraj A.,Ashok Leyland Technical Center | Balachandran G.,Kalyani Carpenter Special Steels Ltd. | Kamaraj M.,Indian Institute of Technology Madras | Kazuya E.,Nagaoka University of Technology
Materials and Design | Year: 2011

The effect of tempering temperature (100-600 °C) on the hardness and wear resistance of a series of quenched and tempered hypereutectic alloyed gray cast irons has been studied in this work. Hardness was observed decreases with increase in tempering temperature and this trend is influenced by alloying additions and the volume of graphite flakes. Hardness of alloyed gray irons is also influenced by solid solution strengthening of tempered ferrite and carbide content and their distribution. The wear loss of alloyed cast irons was found to be lowest at a tempering temperature of 100 °C and 400 °C. The optimum tempering temperature is 400 °C with moderate hardness and low wear rate. This has been attributed to strengthening of the matrix at this temperature. Beyond 400 °C, the wear rate increases significantly due to carbide coagulation. © 2010 Elsevier Ltd.

Balachandran G.,Kalyani Carpenter Special Steels Ltd. | Vadiraj A.,Ashok Leyland Technical Center | Kamaraj M.,Indian Institute of Technology Madras | Kazuya E.,Nagaoka University of Technology
Materials and Design | Year: 2011

Three groups of hypereutectic cast irons alloyed with Cu, Ni and microalloying additive like Ti and Nb were examined for its hardness and wear resistance in the austempered (360 °C/3. h) and quenched and tempered conditions at varying tempering temperatures. It is observed that the cast irons in the quenched and tempered condition showed good wear resistance and moderate hardness at 400 °C. This was comparable with the wear resistance in austempered condition. The study also showed that in quenched and tempered condition, increasing Cu content in cast irons improved its wear resistance moderately while increasing Ni content has decreased its wear resistance. The presence of strong carbide formers (Nb, Ti) did not give significant improvement in wear resistance in quenched and tempered condition. Even in austempered alloys, higher Cu content increases its wear resistance and higher Ni content decreases their wear resistance. The austempered alloys showed ausferritic microstructure with 20% austenite phase which enhances wear resistance through transformation induced plasticity effect. On the other hand, the quenched and tempered alloys showed good wear resistance at 400. °C due to fine tempered carbides in the matrix. © 2011 Elsevier Ltd.

Hariharan K.,Ashok Leyland Ltd. | Kalaivani K.,Ashok Leyland Ltd. | Balachandran G.,Ashok Leyland Ltd. | Balachandran G.,Kalyani Carpenter Special Steels Ltd.
Materials and Manufacturing Processes | Year: 2012

In the present work, double foil butt resistance seam welding in an automotive floor component has been investigated. The possibility of reducing foil from the existing configuration is evaluated. Mechanical properties of the single and double foil weld configuration are compared using tensile tests. The fractography of failed location is analyzed, and the force distribution in base metal and welded specimen is derived analytically to explain the observations in tensile tests. The microstructure and hardness profile of both the weld configurations and their influence on the mechanical properties are analyzed. The weld defect is analyzed using ultrasonic inspection technique. Based on the evaluation of metallurgical characterization and mechanical properties evaluation, the number of foils in an automotive floor component has been optimized. Cost savings of around 30% in the welding process is achieved by foil optimization. © Taylor and Francis Group, LLC.

Dhanasekaran S.,Advanced Engineering Group | Balachandran G.,Kalyani Carpenter Special Steels Ltd.
SAE Technical Papers | Year: 2011

Austempered Ductile Iron (ADI) has emerged in the recent years as a technologically important engineering material. Heat treatment of ductile iron in a salt bath at a temperature range between 250 and 450°C produces ADI. The advantages of ADI are excellent strength, fracture toughness and wear resistance that suit the service conditions of automobile components. It is further considered as an economic substitute for forged steels in certain automobile components. In this present investigation, spheroidal graphite iron, with as-cast ferritic microstructure was cast into automobile components of two different thicknesses. The components were initially austenized and suitably austempered. The effect of austempering heat treatment on the microstructure and mechanical properties were analyzed. The study demonstrates a significant improvement in the ferrite volume fraction and mechanical properties in thinner components. Copyright © 2011 SAE International and Copyright © 2011 SIAT, India.

Balachandran G.,Kalyani Carpenter Special Steels Ltd. | Balasubramanian V.,Kalyani Carpenter Special Steels Ltd.
Advanced Materials Research | Year: 2013

Stainless steel bar and wire products that cater to the high technology application in defence, nuclear, aerospace, oil field and chemical engineering is an area poised for rapid growth in India. The advancing capabilities of alloy steel plants in India have enabled mastering of techniques to make a wide variety of stainless steels. However, there are increasing challenges to meet the advanced property requirements, which call for a basic understanding on the structure property relationship that are influenced by appropriate alloy design and down-stream processing. The special steel industry cater to a wide variety of stainless steels namely ferritic, martensitic, austenitic and precipitation hardenable categories for meeting requirements of high technology. One of the process for making the primary stainless steels is Vacuum Oxygen Decarburisation process. For advanced applications, the primary melted steel is again secondary refined using electroslagremelting for the management of solidification structures and control of inclusions. In the austenitic grades, the hot forged and hot rolled heat treated steels, careful choice of chemistry controls the delta ferrite content and ensures uniformity of the grain size in the product during deformation processing and heat treatment. In the martensitic stainless steel grades, focus is given to delta ferrite, grain size control and appropriate tempering treatment. In the precipitation hardenable steels grades the aging reactions and hot deformation range have to be optimised for deriving specified mechanical properties. Special grades are produced using non ESR and ESR routes to meet high temperature applications such as turbine blades and bolting. In these grades control of delta ferrite content, carbides, carbo-nitrides in the matrix has a deep influence on the mechanical and sub zero fracture properties. In the ferritic stainless steel grade grain size control is critical. The presentation would bring forth the correlation between the alloy design, processing and properties that were achieved in the products mentioned above to meet some of the challenging requirements. © (2013) Trans Tech Publications, Switzerland.

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