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  • Item
    Dry Sliding Wear Behavior of Super Duplex Stainless Steel AISI 2507: A Statistical Approach
    (De Gruyter Open Ltd peter.golla@degruyter.com, 2016) Davanageri, M.; Narendranath, S.; Kadoli, R.
    The dry sliding wear behavior of heat-treated super duplex stainless steel AISI 2507 was examined by taking pin-on-disc type of wear-test rig. Independent parameters, namely applied load, sliding distance, and sliding speed, influence mainly the wear rate of super duplex stainless steel. The said material was heat treated to a temperature of 850°C for 1 hour followed by water quenching. The heat treatment was carried out to precipitate the secondary sigma phase formation. Experiments were conducted to study the influence of independent parameters set at three factor levels using the L27 orthogonal array of the Taguchi experimental design on the wear rate. Statistical significance of both individual and combined factor effects was determined for specific wear rate. Surface plots were drawn to explain the behavior of independent variables on the measured wear rate. Statistically, the models were validated using the analysis of variance test. Multiple non-linear regression equations were derived for wear rate expressed as non-linear functions of independent variables. Further, the prediction accuracy of the developed regression equation was tested with the actual experiments. The independent parameters responsible for the desired minimum wear rate were determined by using the desirability function approach. The worn-out surface characteristics obtained for the minimum wear rate was examined using the scanning electron microscope. The desired smooth surface was obtained for the determined optimal condition by desirability function approach. © 2016 M. Davanageri et al., published by De Gruyter Open 2016.
  • Item
    Influence of ageing time on hardness, microstructure and wear behaviour of AISI2507 super duplex stainless steel
    (Institute of Physics Publishing helen.craven@iop.org, 2017) Davanageri, M.; Narendranath, S.; Kadoli, R.
    The effect of ageing time on hardness, microstructure and wear behaviour of super duplex stainless AISI 2507 is examined. The material was solution treated at 1050 °C and water quenched, further the ageing has been carried out at 850 °C for 30 min, 60 min and 90 min. The chromium (Cr) and molybdenum (Mo) enriched intermetallic sigma phase (?) were found to precipitate at the ferrite/ austenite interface and within the ferrite region. The concentration of intermetallic sigma phase (?), which was quantified by a combination of scanning electron microscopy and image analysis, increases with increasing ageing time, leading to significant increase in the hardness. The x-ray diffraction (XRD) and energy dispersive x-ray (EDX) was employed to investigate the element distribution and phase identification. Wear characterstics of the aged super duplex stainless steel were measured by varying normal loads, sliding speeds, sliding distance and compared with solution treated (as-cast) specimens. Scanning electron microscopy was used to assist in analysis of worn out surfaces. The outcomes suggested that the increase in percentage of sigma phase increases hardness and wear resistance in heat-treated specimens compared to solution treated specimens (as-cast). © 2017 IOP Publishing Ltd.
  • Item
    Modeling and Optimization of Wear Rate of AISI 2507 Super Duplex Stainless Steel
    (Springer Netherlands rbk@louisiana.edu, 2019) Davanageri, M.B.; Narendranath, S.; Kadoli, R.
    The present work attempts to study the parameters influencing wear, namely, applied load, heat-treated temperature, sliding velocity, and sliding distance using statistical Design of Experiments (DOE) and Response Surface Methodology (RSM). The wear behavior of super duplex stainless steel was evaluated under dry sliding conditions. A three-level Central Composite Design (CCD) based non-linear model was used to establish input-output relationship based on the collected experimental input-output data. Surface plots were used to study the influence of applied load, heat-treated temperature, sliding distance, and sliding velocity on the wear rate of super duplex stainless steel. The wear rate was observed to vary nearly non-linearly with applied load and linearly with the rest of the input parameters. Analysis of Variance (ANOVA) was conducted to test the statistical adequacy of the non-linear model developed. Applied load and heat-treated temperature were found to have a more positive contribution towards the wear rate than other parameters. Although the sliding velocity had a negligible effect, its interaction with applied load and heat-treated temperature had a significant impact on the wear rate. The regression equation developed was tested for its prediction precision with the help of 20 test cases. Further, attempts were also made to determine the optimum combination of input parameters that minimize the wear rate using the Desirability Function Approach (DFA). The objective of minimizing the wear rate was met with the highest desirability value of 1. Confirmation experiments were conducted for the determined optimal set of input parameters of 20 test cases resulting in an average absolute percent deviation in prediction of 6.34% and 5.58%. © 2018, Springer Science+Business Media B.V., part of Springer Nature.