Title: Multi-response optimisation of the deep cryogenic treatment for 21-4N valve steel

Authors: M. Arockia Jaswin; D. Mohan Lal

Addresses: Department of Mechanical Engineering, Aksheyaa College of Engineering, Puludivakkam, Chennai 603 314, India. ' Department of Mechanical Engineering, College of Engineering Guindy, Anna University Chennai, Chennai 600 025, India

Abstract: This paper deals with the optimisation of the deep cryogenic treatment process for 21-4N valve steel to maximise the tensile strength, hardness and wear resistance using Grey-Taguchi method. The factors considered for the optimisation are the cooling rate, soaking temperature, soaking period and aging temperature, each at three different levels. Nine experimental trials based on the L9 (34) orthogonal array were conducted. The analysis of variance (ANOVA) is performed to identify the significant contribution of parameters. A confirmation test is conducted to validate the test result. The improvement in tensile strength, hardness and wear resistance from the untreated samples to the deep-cryo treated samples at the optimised treatment condition are 11.87%, 15.32% and 27.8% respectively. The result of the confirmation experiment shows that the responses are improved simultaneously through the optimal combination of the deep cryogenic treatment parameters obtained from the proposed method.

Keywords: valve steel; deep cryogenic treatment; DCT; Taguchi methods; grey relational analysis; GRA; analysis of variance; ANOVA; tensile strength; hardness; wear resistance; cooling rate; soaking temperature; soaking period; aging temperature.

DOI: 10.1504/IJEDPO.2011.043569

International Journal of Experimental Design and Process Optimisation, 2011 Vol.2 No.4, pp.357 - 372

Published online: 11 Oct 2014 *

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