Welding simulation of steels welded with low transformation temperature (LTT) filler materials

Examensarbete för masterexamen

Please use this identifier to cite or link to this item: https://hdl.handle.net/20.500.12380/239160
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Type: Examensarbete för masterexamen
Master Thesis
Title: Welding simulation of steels welded with low transformation temperature (LTT) filler materials
Authors: Esfahani, Minaalsadat Mirhendi
Abstract: Welding is a thermal process that creates residual stresses due to a combination of thermal expansion, plastic flow and phase transformation. By using filler material which has a composition that transforms to phase transformation to Martensite at low temperatures, the residual stress state can become more favorable. The purpose of this thesis is to develop a numerical tool to evaluate temperature evolution, phase transformations and residual stresses developing during multi-pass plate-to-plate welding using LTT filler. The commercially available finite element (FE) software Abaqus v6.13 (Simulia 2013) was used for the numerical simulations. In the current thesis a transient 3D simulation of a moving heat source with a distributed heat flux is performed. First a repeated analysis of a single pass weld is performed to validate Abaqus as a good simulation software for welding simulation. Then a heat transfer analysis of a plate with 3 pass of weld is performed. Two different heat source models are used and compared. The Abaqus user subroutine DFLUX is used to define the welding torch heat input as a volumetric heat flux. The subroutine is developed in the FORTRAN language. The heat source travels along the weld line to simulate the torch movement. In the next phase of the work, Metallurgical analysis is performed to model the phase transformation during and after welding. User subroutine Hetval is used to model phase transformation. Finally, the data from the previous heat transfer analysis and metallurgical analysis are used as an input file for a mechanical analysis.
Keywords: Materialvetenskap;Produktion;Grundläggande vetenskaper;Hållbar utveckling;Övrig bearbetning/sammanfogning;Metallurgisk process- och produktionsteknik;Materials Science;Production;Basic Sciences;Sustainable Development;Other processing/assembly;Metallurgical process and manufacturing engineering
Issue Date: 2016
Publisher: Chalmers tekniska högskola / Institutionen för material- och tillverkningsteknik
Chalmers University of Technology / Department of Materials and Manufacturing Technology
Series/Report no.: Diploma work - Department of Materials and Manufacturing Technology, Chalmers University of Technology : 181/2016
URI: https://hdl.handle.net/20.500.12380/239160
Collection:Examensarbeten för masterexamen // Master Theses (IMS)

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