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- Englisch (3)
Schlagworte
- Welding simulation (3)
- Eigenspannungen (2)
- Martensitbildung (2)
- Martensite kinetic (2)
- Residual stresses (2)
- Schweißsimulation (2)
- Sensitivity analysis (2)
- Sysweld (2)
- C-Mn steels (1)
- CCT sensitivity (1)
Continuous cooling transformation (CCT) behavior affects the transient state of
material properties employed in a numerical welding simulation, having a direct influence
on the developing stress state. Three different CCT diagrams for S355J2 steel
were employed to understand the influence of variations in CCT behavior on the numerical
calculation of welding-induced residual stresses. The CCT diagrams were
constructed from transformation data contained in the Sysweld software database,
measured dilatometric data from Gleeble experiments, and transformation data calculated
from the JMatPro software. The calculated transverse and longitudinal residual
stress distributions provided a qualitative correction only in comparison to experimental
measurements, with the largest deviation occurring near the weld
interface. Overall, the results indicate a weak dependency of the calculated residual
stresses due to anticipated CCT variations. The most significant effect on the calculated
residual stresses was shown to be related to the proportion of formed martensite.
It is suggested that CCT data of approximate accuracy is sufficient for reliable
calculation of welding-induced residual stresses.
The usage of continuous cooling transformation (CCT) diagrams in numerical welding simulations is state of the art. Nevertheless, specifications provide limits in chemical composition of materials which result in different CCT behavior and CCT diagrams, respectively. Therefore, it is necessary to analyze the influence of variations in CCT diagrams on the developing residual stresses. In the present paper, four CCT diagrams and their effect on numerical calculation of residual stresses are investigated for the widely used structural steel S355J2 + N welded by the gas metal arc welding (GMAW) process. Rather than performing an arbitrary adjustment of CCT behavior, four justifiable data sets were used as input to the numerical calculation: data available in the Sysweld database, experimental data acquired through Gleeble dilatometry tests, and TTT/CCT predictions calculated from the JMatPro and Edison Welding Institute (EWI) Virtual Joining Portal software. The performed numerical analyses resulted in noticeable deviations in residual stresses considering the different CCT diagrams. Furthermore, possibilities to improve the prediction of distortions and residual stress based on CCT behavior are discussed.