doi:10.3723/ut.38.013 Underwater Technology, Vol. 38, No. 1, pp. 13–16, 2021
Non-linear finite element analysis of a Ti6Al4V/Inconel 625 joint obtained by explosion welding for sub-sea applications
Technical Paper
www.sut.org
Pasqualino Corigliano* Department of Engineering, University of Messina, Contrada di Dio - 98166, Messina, Italy Received 13 August 2020; Accepted 11 January 2021
Abstract Industries have shown interest in the use of dissimilar metals to make corrosion-resistant materials combined with good mechanical properties in marine environments. Explosive welding can be considered a good method for joining dissimilar materials to prevent galvanic corrosion. The aim of the present study was to simulate the non-linear behaviour of a Ti6Al4V/Inconel 625 welded joint obtained by explosion welding from the values of the tensile ultimate strength and yielding strength of the parent materials. The present study compared the stress-strain curve from tensile loading obtained by the non-linear finite element analysis with the experimental stress-strain curve of a bimetallic joint. The applied method provides useful information for the development of models and the prediction of the structural behaviour of Ti6Al4V/Inconel 625 explosive welded joints. Keywords: explosive welded joints, non-linear finite element analysis, marine structures
1. Introduction The task of joining different materials represents an important challenge, and in recent decades the explosion welding technique has become popular. Developments in explosive welding have been reviewed by Findik (2011), and bimetallic welded joints for marine application have been investigated by Young and Banker (2004). The predominant explosive welded joint used in the marine industry is the Al/Steel type joint for shipbuilding applications, and several experimental investigations have been reported (Corigliano et al., 2018a; 2018b; Kaya, 2018; Han et al., 2003; Li et al., 2015; Findik, 2011; McKenney and Banker, 1971; Acarer and Demir, 2008; Chao et al., 1997). In addition to the Al-steel joint, other dissimilar materials can be used in marine environments, such as stainless steel and Inconel 625 joints (Milititsky et al., 2010). * Contact author. Email address: pcorigliano@unime.it
Industries have shown interest in deeper-depth drilling, creating the need for new materials that can fulfil more requirements such as protection from corrosion, reduction of self-weight and higher strength (Alemán et al., 1995). Within this context, stainless steel alloys could be replaced by titanium alloys, which have a good combination of strength, creep resistance and resistance to corrosion. Since titanium has a higher potential than most other metals commonly used in seawater piping systems, it is the other metal, and not titanium, that becomes corroded. If another metal with equal galvanic potential is used (i.e. Alloy 625) throughout the system, galvanic corrosion will not occur (Francis et al., 2020). It has been shown that Ti – Inconel (Nickel alloy 625) coupling can be used for marine applications, as they belong to the same group (Francis et al., 2020). However, if traditional welding techniques are used, these materials would be difficult to join, and corrosion would not be avoided. Explosion welding for bimetallic materials has been developed to overcome such difficulties, using material of high strength metallurgically bonded to a thin corrosionresistant clad alloy. The aim of the present study was to simulate the non-linear behaviour of a Ti6Al4V/Inconel 625 joint produced by explosion welding starting from the values of the tensile ultimate strength and yielding strength of the parent metals, and to observe differences in experimental tests. In recent work, Topolski et al. (2016) investigated the microstructure and properties of a bimetallic Ti6Al4V/Inconel 625; this investigation served as reference for the comparison of the non-linear finite element analysis of the present study. The present author has previously applied procedures, based on finite element analysis (FEA) and validated by means of experimental data, for the analysis of Al-Steel explosive welded joints under static and fatigue loadings (Corigliano et al., 2018a; 2018b), 13
