scholarly journals Fatigue Performance of High- and Low-Strength Repaired Welded Steel Joints

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 293
Author(s):  
Jan Schubnell ◽  
Phillip Ladendorf ◽  
Ardeshir Sarmast ◽  
Majid Farajian ◽  
Peter Knödel
Keyword(s):  
Cyclic Loading ◽  
Gas Metal Arc Welding ◽  
Crack Depth ◽  
Destructive Testing ◽  
Welded Steel ◽  
Railway Bridges ◽  
Residual Stress State ◽  
Metal Arc Welding ◽  
Original Specimen ◽  
Steel Joints

Large portions of infrastructure buildings, for example highway- and railway bridges, are steel constructions and reach the end of their service life, as a reason of an increase of traffic volume. As lifetime extension of a commonly used weld detail (transverse stiffener) of these structures, a validated approach for the weld repair was proposed in this study. For this, welded joints made of S355J2+N and S960QL steels were subjected to cyclic loading until a pre-determined crack depth was reached. The cracks were detected by non-destructive testing methods and repaired by removal of the material around the crack and re-welding with the gas metal arc welding (GMAW). Then, the specimens were subjected to cyclic loading again. The hardness, the weld geometry, and the residual stress state was investigated for both the original- and the repaired conditions. It was determined that nearly all repaired specimens reached at least the fatigue life of the original specimen.

Mechanical properties and microstructural characteristics of rotating arc-gas metal arc welded carbon steel joints

2021 ◽  
Vol 30 (1) ◽  
pp. 49-58
Author(s):  
Nallasamy Sankar ◽  
Sudersanan Malarvizhi ◽  
Visvalingam Balasubramanian
Keyword(s):  
Mechanical Properties ◽  
Carbon Steel ◽  
Weld Metal ◽  
Gas Metal Arc Welding ◽  
Ferrite Matrix ◽  
Metal Arc Welding ◽  
Rotating Arc ◽  
Steel Joints ◽  
Welding Processes ◽  
Lamellar Pearlite

Abstract The main problem associated with high thickness carbon steel plate's narrow range or “V” groove welding in conventional welding processes is the sagging of the molten pool due to gravity, which in turn leads to defects formation and deteriorates mechanical properties. This problem could be overcome by the rotating arc gas metal arc welding (RA-GMAW) technique. This investigation aims to evaluate mechanical properties and metallurgical characteristics of high thickness IS2062 Gr-B carbon steel joints welded by RA-GMAW technique. The experimental results show that RA-GMAW joint exhibited higher (598 MPa) tensile strength, higher hardness (220 HV) at weld metal region, and lower impact toughness (137 J) than the unwelded base metal. This is due to the presence of fine acicular ferrite and widmanstatten ferrite matrix mixed with fine lamellar pearlite microstructure in the weld metal region.

Integration of Welding, NDT, Mechanical Testing and Field Control When Using an ECA Flaw Acceptance Criteria in Pipeline Construction

2018 ◽  
Author(s):  
Junfang Lu ◽  
Bob Huntley ◽  
Luke Ludwig ◽  
Axel Aulin ◽  
Andy Duncan
Keyword(s):  
Mechanical Testing ◽  
Gas Metal Arc Welding ◽  
Probability Of Detection ◽  
Destructive Testing ◽  
Acceptance Criteria ◽  
Pipeline Construction ◽  
High Productivity ◽  
Metal Arc Welding ◽  
Field Control ◽  
Girth Welds

The fracture mechanics based engineering critical assessment (ECA) method has been accepted as a fitness for service (FFS) approach to defining weld flaw acceptance criteria for pipeline girth welds. Mechanized gas metal arc welding (GMAW) processes are commonly used in cross country pipeline girth weld welding because of the advantages in good quality and high productivity. With the technical advancements of non-destructive testing (NDT) techniques, automated ultrasonic testing (AUT) has greatly improved flaw characterization, sizing and probability of detection during weld inspection. Alternative weld flaw acceptance criteria are permitted in pipeline construction code to assess the acceptability of mechanized girth welds using an ECA. The use of an ECA based weld flaw acceptance criteria can significantly reduce the construction cost. Mechanized girth weld acceptance criteria have been progressively transitioned from workmanship standards into using fitness for service based ECAs. To successfully deliver an ECA on a pipeline project, a multidisciplinary approach must be taken during the welding design and construction stages. Welding, NDT, mechanical testing and field control are all integral elements of pipeline construction. All these four elements have to be fully integrated in order to implement the ECA and achieve the overall integrity of a pipeline. The purpose of this paper is to discuss the importance of the integration of these four elements necessary for proper implementation of the ECA weld flaw acceptance criteria.

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