NUMERICAL STUDY OF THERMAL AND STRUCTURAL STRAINS IN MULTIPASS GMAW SURFACING AND REBUILDING

1 Gawrońska Elżbieta
Co-authors:
1 Winczek Jerzy
Institution:
1 Czestochowa University of Technology, Czestochowa, Poland, EU, elzbieta.gawronska@icis.pcz.pl, winczek@gmail.com
Conference:
24th International Conference on Metallurgy and Materials, Hotel Voronez I, Brno, Czech Republic, EU, June 3rd - 5th 2015
Proceedings:
Proceedings 24th International Conference on Metallurgy and Materials
Pages:
655-660
ISBN:
978-80-87294-58-1
ISSN:
2694-9296
Published:
12th January 2015
Proceedings of the conference were published in Web of Science and Scopus.
Metrics:
255 views / 89 downloads
Abstract

The paper presents the calculations of temperature field, volume fractions of structural components and strains during multipass GMAW surfacing of a prismatic element made of S235 steel. The bimodal heat source model is used in the description of temperature field. The solution takes into consideration the heating caused by the welding heat source during overlaying subsequent weld beads and self-cooling of already padded areas. The highest temperatures enable to determine characteristic heat-affected zones. The critical temperatures A1 and A3 are used to determine partial and full austenitic transformation zones, while the temperature of solidus is used to determine the fusion line. Kinetics of phase changes during heating is limited by temperature values at the beginning (A1) and at the end (A3) of austenitic transformation. In order to quantitatively describe the dependence of structure and material quality on temperature and transformation time of over-cooled austenite during surfacing, time-temperature-transformation at continuous cooling (TTT) welding diagram is used. The structural and thermal expansion coefficient values are determined on the basis of authors’ own dilatometric research. For calculations are used authors’ programs made in Borland Delphi. The results are presented in the form of temperature and volume phase fraction distributions in the element’s cross section as well as thermal cycles of volume phase fractions and strains at selected points.

Keywords: multipass welding, temperature field, phase transformation, strains, GMA

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