Abstract:
The state of residual stress in welded joints is a well-studied topic, and many
methodsof residual stress measurement are now available. However, far less is
known aboutthe transient strains which occur during the welding process, even
though these are thedirect cause of residual stresses. Efforts to model welding
processes usually includetransient stresses and strains among their results, but
in general these models can onlybe easily compared against experimentally
measured residual stresses: there is a lackof published data covering strain in
the transient regime.In this study, electrical resistance strain gauges were
used to measure transient strainsduring welding, and comparison is made between
these measurements and the resultsfrom a sequential thermo-mechanical finite
element model of the process. Well-definedmechanical boundary conditions were
used for the experiments to ease interpretationof the measured strain data, and
to enable close approximation with the boundaryconditions of the computational
model. The transient biaxial state of strain wasmeasured during Gas Metal Arc
Welding (GMAW) of S355 steel samples in a bead-onplateconfiguration. Measured
transient strains were found to be consistent betweensamples, and showed good
agreement with the modelling results. It is hoped thatfuture study of welding
transient strains will aid in the optimisation of in-processmethods to reduce
residual stress, such as rolling and quench cooling.
