Title: Modelling and optimisation of the post-weld heat treatment of γ′ precipitation and hardness on Inconel X-750 using the response surface methodology

Authors: Prachya Peasura; Bovornchok Poopat

Addresses: Department of Production Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, 10140, Thailand ' Department of Production Engineering, Faculty of Engineering, King Mongkut's University of Technology Thonburi (KMUTT), Bangkok, 10140, Thailand

Abstract: This work describes a post-weld heat treatment (PWHT) for Inconel X-750. The following PWHT variables were examined: the solution temperature, PWHT temperature, and PWHT time. In this research, the application of the response surface methodology and Box-Behnken design in a mathematical model was investigated and optimised. The resulting materials were examined using optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM) in the fusion zone (FZ). The experimental results reveal that using a full quadratic model with the proposed mathematical model of the γ′ precipitation size and γ′ hardness in the FZ, the obtained correlation of the hardness and γ′ precipitate size showed a reasonable linear relationship.

Keywords: post-weld heat treatment; solution temperature; PWHT temperature; PWHT time; Inconel X-750; response surface methodology; RSM; precipitate size; hardness; modelling; optimisation; Box-Behnken design; mathematical modelling.

DOI: 10.1504/IJMPT.2016.075494

International Journal of Materials and Product Technology, 2016 Vol.52 No.3/4, pp.238 - 259

Received: 03 Dec 2014
Accepted: 13 Mar 2015

Published online: 11 Mar 2016 *

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