The Influence of the Heat-Affected Zone Mechanical Properties on the Behaviour of the Welding in Transverse Plate-to-Tube Joints

Abstract

Eurocode 3 establishes the component method to analytically characterize the structural joints between beam and columns. When one of the members involved in the joint is a hollow section (i.e., a tube) there is a lack of information for the specific components present in the joint. There are two different ways to bridge the gap: experimental testing on the actual beam column joints involving tubular sections; or numerical modelization, typically by means of finite element analysis. For this second option, it is necessary to know the actual mechanical properties of the material. As long as the joint implies a welding process, there is a concern related to how the mechanical properties in the heat-affected zone (HAZ) influence the behavior of the joint. In this work, some coupons were extracted from the HAZ of the beam-column joint. The coupons were tested and the results were implemented in the numerical model of the joint, in an attempt to bring it closer to the experimental results of the tested joints.

The Resistance of Welded Joints of Galvanized RHS Trusses with Different Vent Hole Geometries

“…For weld modeling, the same material properties as those of the corresponding welded brace member were adopted. Some previous research [24,38] carried out in similar situations has confirmed that differences when the base material properties of the steel are also used to model the welds are not noticeable. Although some gaps were smaller than those in EN-1993-1-8 [4], the tests were carried out prior to the formulation of the code, and they were used in this research only for validation of the numerical model.…”

“…Although pre-galvanizing countermeasures should be considered to avoid cases of brittle cracking resulting from hot-dip galvanizing on cold-formed tubes [21,22], when the process is carried out correctly, this embrittlement effect has been found to be negligible, even in hot-dip galvanized welded joints submitted to fatigue loads [23]. Together with all the previous statements, we can assume that the heat-affected zone (HAZ) in structural steel, and particularly in HSS, does not affect the welded joint behavior [24].…”

“…However, this was not really modeled in the previous work mentioned, which only considered an estimation of the thermal effects of the weld process. This lack of geometrical weld modeling is solved in this new paper, and the thermal effects mentioned were neglected, since neither the bibliography nor the previous work carried out by the authors [24] showed any appreciable influence of this factor. •…”

Probability life calculation model of beam element application and study in welded structures reliability analysis

“…Scholars divide the vicinity of weld into weld seam, overheated zone, normalized zone, partial normalized zone and grain refined zone in detail. 35 Because the mechanical properties of the weld material are better than those of the base material, using the fatigue coefficient of the base material instead of the weld material coefficient can obtain a safer design criterion. Moreover, the decrease of mechanical properties in heat affected zone is caused by the increase of austenite and the coarsening of grain, so it can be regarded as the increase of initial defect distribution.…”

Comparative behaviour of ‘I beam- RHS column’ joints with and without web weld

“…(2) For welds, comments regarding the mechanical properties in the heat-affected zone [23] where considered. The nominal yield limit and ultimate strength values provided by the electrode manufacturer were used, being f y =500 MPa and f u =570 MPa respectively.…”