A New Approach to Simulate HSLA Steel Multipass Welding through Distributed Point Heat Sources Model

Mechanical properties of welded joints depend on the way heat flows through the welding passes. In multipass welding the reheating of the heat affected zone (HAZ) can form local brittle zones that need to be delimited for evaluation. The difficulty lies in the choice of a model that can simulate mul...

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Bibliographic Details
Published inMetals (Basel ) Vol. 8; no. 11; p. 951
Main Authors Ferreira, Dario, Alves, Antonio, Cruz Neto, Rubelmar, Martins, Thiago, Brandi, Sérgio
Format Journal Article
LanguageEnglish
Published Basel MDPI AG 01.11.2018
Subjects
API 5L X80 steel
Boundary conditions
distributed point heat sources model
Filler metals
Flux core wire welding
Gas metal arc welding
Heat affected zone
Heat sources
Heat transfer
Heat transmission
Heating
High strength low alloy steels
local brittle zone
Local brittle zones
Mechanical properties
medium thick plate model
Microstructure
Photomacrographs
Physical properties
Radiation
Short circuits
Simulation
Software packages
Temperature
Temperature dependence
Thick plates
Welded joints
Welding fluxes
welding thermal cycles
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Summary:Mechanical properties of welded joints depend on the way heat flows through the welding passes. In multipass welding the reheating of the heat affected zone (HAZ) can form local brittle zones that need to be delimited for evaluation. The difficulty lies in the choice of a model that can simulate multipass welding. This study evaluated Rosenthal’s Medium Thick Plate (MTP) and the Distributed heat Sources (DHS) of Mhyr and Gröng models. Two assumptions were considered for both models: constant and temperature-dependent physical properties. It was carried out on a multipass welding of an API 5L X80 tube, with 1016 mm (42″) external diameter, 16 mm thick and half V-groove bevel, in the 3G up position. The root pass was welded with Gas Metal Arc Welding (GMAW) process with controlled short-circuit transfer. The Flux Cored Arc Welding (FCAW) process was used in the filling and finishing passes, using filler metal E111T1-K3M-JH4. The evaluation criteria used were overlapping the simulated isotherms on the marks revealed in the macrographs and the comparison between the experimental thermal cycle and those simulated by the proposed models. The DHS model with the temperature-dependent properties presented the best results and simulated with accuracy the HAZ of root and second welding passes. In this way, it was possible to delimit the HAZ heated sub-regions.
ISSN:2075-4701
2075-4701
DOI:10.3390/met8110951