Title: The effect of nitriding on the toughness and bending resistance of tool steels

Authors: Jan Vatavuk, Lauralice C.F. Canale, George E. Totten, Sergio G. Cardoso

Addresses: Departamento de Engenharia de Materiais, Universidade Presbiteriana Mackenzie, Sao Paulo, SP, Brazil. ' Departamento de Engenharia de Materiais, Aeronautica e Automobilistica, Escola de Engenharia de Sao Carlos, Universidade de Sao Paulo, Av. Trabalhador Sao-carlense 400, Sao Carlos, SP 13566–590, Brazil. ' Department of Mechanical and Materials Engineering, Portland State University, P.O. Box 751, Portland OR 97207–0751, USA. ' Departamento de Engenharia de Materiais, Universidade Presbiteriana Mackenzie, Sao Paulo, SP, Brazil

Abstract: Recently a detailed study was performed with the nitrided and non-nitrided tool steels AISI H13, AISI D2, AISI D6, AISI M2 and K340. Different nitriding processes, including gas, salt bath and also salt bath plus diffusion heat treatment, were performed and compared. The performance of the tool steels was evaluated using bending tests and impact tests. Microstructure characterisation was performed using optical microscopy. The nitriding treatment prompts a reduction in the rupture modulus and absorbed energy in an unnotched impact specimen. Lower mechanical properties were obtained in the gas nitrided samples due to the deeper diffusion layers achieved by these thermochemical processes. The reduction in the white layer thickness by the diffusion treatment in the salt nitrided samples has no effect on the mechanical response of the tested samples. The results show that the impact absorption energy tests have the worst effect in terms of reduction due to the nitriding processes.

Keywords: nitriding; tool steels; toughness; bending resistance; impact tests; microstructure.

DOI: 10.1504/IJMMP.2008.022036

International Journal of Microstructure and Materials Properties, 2008 Vol.3 No.4/5, pp.563 - 575

Published online: 17 Dec 2008 *

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