TITLE:
Residual Stress and Fracture Toughness Study in A516 Gr70 Steel Joints Welded and Repaired by Arc Processes
AUTHORS:
Régis de Matos Curvelo de Barros, Mauricio David Martins das Neves
KEYWORDS:
Weld Repair, Weld Fatigue, Weld J Integral, Residual Stress, Microharness
JOURNAL NAME:
Engineering,
Vol.15 No.11,
November
28,
2023
ABSTRACT: Structural components made of steel are used in several areas and require
welding for assembly. In some situations, repair of the weld bead, also
performed by electric arc welding, can be used to correct, and eliminate any
discontinuities. However, electric arc welding causes the presence of residual
stresses in the joint, which can impair its performance and not meet specific
design requirements. In this paper, welded joints made of ASTM A 516 GR 70
steel plates, with a thickness of 30.5 mm, welded by the MAG—Metal Active Gas process (20% CO2)
and using a “K” groove were analysed. The joints were manufactured with seven welding passes on each side of the groove.
After welding, one batch underwent repair of the bead by TIG welding
(Tungsten Insert Gas) and another batch underwent two repairs by TIG welding.
Were presented results of the behaviour of the residual stress profile measured
by X-ray diffraction and the Vickers microhardness profile in the joints as
well the fracture toughness in the conditions only welded and submitted to
repairs. The results indicated that the greater number of repair passes reduced
the residual compressive stress values obtained in the material manufacturing
process and caused a stabilization on the Vickers hardness values. It was
concluded that compressive residual stresses did not play a major role in the
R-curve results. The presence of discontinuities in the welded joint caused
greater influence on the behaviour of the R curve.