An Improved Simulation of Temperature Field in PMHW of Ti-6Al-4V Alloy

Abstract

ABSTRACTThis paper describes a coaxial plasma–MIG hybrid welding (PMHW) method to improve the welding quality of titanium alloy plates. Aiming at the temperature field analysis of a Ti-6Al-4V alloy plate in the PMHW process, an improved hybrid heat source model capable of accurately characterising the heat input of a hybrid arc on workpieces and the arc deflection phenomenon, is proposed. Experiments were conducted on 4-mm Ti-6Al-4V plates in PMHW surfacing, and a corresponding simulation analysis was performed. To calculate the weld geometry, a weld pool shape was used in accordance with the experimental results. The results showed that, as plasma current increased from 60 A to 80 A, the weld reinforcement and offset Δd decreased, and the size of the weld pool increased. Plasma arc power had a greater effect on the length than on the width of the molten pool. Hybrid arcs had a stronger penetrating ability; hence, achieving deep penetration welding and high welding efficiency in the PMHW of the Ti-6Al-4V alloy was easier. Microstructure analysis showed that the Ti-6Al-4V alloy base metal zone was organised by α- and β-phase transformations; β grains in the weld zone were internally formed by a mixture of Weischer tissue and net basket tissue; and the size of β grains in the heat-affected zone decreased with the increase in the distance from the weld.Keywords: plasma–MIG hybrid weldingmodeling and simulationtemperature fieldtitanium alloyDisclaimerAs a service to authors and researchers we are providing this version of an accepted manuscript (AM). Copyediting, typesetting, and review of the resulting proofs will be undertaken on this manuscript before final publication of the Version of Record (VoR). During production and pre-press, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal relate to these versions also. AcknowledgmentsThe generous support of Guangdong Welding Institute (China-Ukraine E.O. Paton Institute of Welding) is also highly acknowledged.Conflicts of InterestThe authors declare no conflicts of interest.