Numerical investigation of the influence of FSW parameters on the heat and mass transfer of austenitic stainless steels

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RESEARCH PAPER

Numerical investigation of the influence of FSW parameters on the heat and mass transfer of austenitic stainless steels Yuri C. da Silva1

2 · Jorge F. dos Santos3 · Francisco Marcondes2 · Cleiton Silva2 ´ · Francisco J. V. Oliveira Junior

Received: 12 March 2020 / Accepted: 13 August 2020 © International Institute of Welding 2020

Abstract The friction stir weld (FSW) method was developed in 1991 by The Welding Institute (TWI) and is very useful for manufacturing components with low fusion weldability. The success of this relatively new technique is due, in part, to an appropriate combination of some parameters. In order to understand the influence of the parameters such as rotation speed, axial force, and welding velocity, simulations were carried out using the AISI 304L stainless steel. In this work, the process was considered to be a 3D non-Newtonian fluid and the heat input was calculated from the friction between the tool and the plate and from the plastic deformation. The thermal results were compared with the experimental results from the thermocouple measurements. Furthermore, the material flow was related to the formation of defects observed in the experimental welds. The results of the simulation were able to determine the temperature distribution and heat flow, as well as to predict defects in the welding. The simulated viscosity values enabled the prediction of the parameters most likely to cause the formation of flashes. In addition, the injection of inert particles into the model made it possible to predict the formation of wormholes. Keywords FSW · Numerical simulation · Heat transfer · Mass transfer · wormholes

Recommended for publication by Commission III - Resistance Welding, Solid State Welding, and Allied Joining Process.  Yuri C. da Silva

[email protected] Francisco J. V. Oliveira J´unior [email protected] Jorge F. dos Santos [email protected] Francisco Marcondes [email protected] Cleiton Silva [email protected] 1

Department of Teaching, Crate´us Campus, Federal Institute of Education, Science and Technology of Cear´a - IFCE, Crat´eus, CE 63708-260, Brazil

2

Department of Metallurgical and Materials Engineering, Center of Technology, Campus of Pici, Universidade Federal do Cear´a - UFC, Fortaleza, CE 60455-760, Brazil

3

Helmholtz-Zentrum Geesthacht GmbH, Institute of Materials Research, Materials Mechanics, Solid State Joining Processes, Geesthacht, 21502, Germany

1 Introduction Since the advent of friction stir welding (FSW) in 1991, which was developed by The Welding Institute (TWI) [1], different materials have been welded successfully by this technique including stainless steels. Initially, the FSW technique was used for low melting point alloys such as aluminum and magnesium. Thomas and Nicholas [2] described the advantages of FSW in aluminum alloys for the transportation industries. However, the development of new materials for the FSW tool has enabled other metals, such as steels, to be welded by the FSW technique. Nandan et al. [3] describe