Thermomechanical simulation of an industrial quenching process applied to a centrifugal pump impeller

Abstract

The thermomechanical behaviour during the quenching process of a centrifugal pump impeller made of white iron is studied in this work. The analysis is carried out using a coupled thermomechanical formulation that is discretized within the context of the finite element method. The material response is described by means of a thermoplastic model that includes phase-change effects. In particular, a heat treatment consisting in cooling from the austenizing temperature is presented with the aim of assessing the failure occurrence of the part at the end of the process. Three different criteria written in terms of the stresses and plastic deformations developed during the cooling stage are specifically compared to evaluate the final mechanical damage. The study is focused on two impeller configurations, with 4 and 5 blades, where fracture occurs in the former during its industrial production. The numerical results obtained in this work for these two cases confirm that the proposed methodology realistically predicts their failure possibilities.