Tesis
Analysis and estimation of extension of the fusion zone and sub-regions of the heat affected zone through neural networks in weld beads produced by GMAW process
Fecha
2021-06-23Registro en:
CAIO, Leandro Bruno Alves. Analysis and estimation of extension of the fusion zone and sub-regions of the
heat affected zone through neural networks in weld beads produced by GMAW process. 2021. xx, 97 f., il. Dissertação (Mestrado em Sistemas Mecatrônicos)—Universidade de Brasília, Brasília, 2021.
Autor
Caio, Leandro Bruno Alves
Institución
Resumen
This study aims to evaluate the use of sensor fusion, based on neural networks,
to estimate the extension of the fusion zone and of the sub-regions of heat affected zone
in GMAW processes. Three samples were produced by depositing weld beads composed
by AWS ER70S-6 wire on SAE 1020 steel plates varying the welding voltage, travel
speed, and wire-feeding speed. Furthermore, the deposition parameters were varied
during the deposition in each of the samples. The infrared radiation profiles emitted from
the samples were gathered using the thermographic camera. The final microstructure was
characterized by Optical Microscopy, Scanning Electron Microscopy and X-ray
Diffraction. Finally, estimation models of the microstructure of weld beads are developed.
The results obtained showed a gradual reduction in the fractions of the predominant
phases of the fusion zone until the existence of only primary and perlite ferrite as the
distance from the melting line increases. With the data obtained by thermography,
microscopy and the welding parameters acquired by the interface, 6 network models (A
to F) were proposed testing different configurations. The Model F with 17 and 15 neurons
in the 1st and 2nd hidden layers trained with Bayesian Regularization and 4 training
cycles showed good results in comparison with the other models (average error of 12.9%)
and was satisfactory in terms of practicality in estimate of the microstructure of the
welded region.