ALBUQUERQUE, S. F.; http://lattes.cnpq.br/9012965466299574; ALBUQUERQUE, Siderley Fernandes.
Resumen:
The objective of this study was to evaluate the influence of robotic and
mechanized welding processes on the microstructure and mechanical
properties of welded joint of API 5LX80 steel used in pipelines to transport oil
and gas. For this plates of this steel were welded by manual Shielded Metal
Arc Welding (SMAW) process with interpasses temperatures of 473 e 673 K,
and using AWS E8010-G electrode as filler metals ; robotized Flux Cored Arc
Welding (FCAW) process, using AWS E71T-1C wire with a diameter of 1.2 mm
and Ar25%C02 as consumable and mechanized Gas Tungsten Arc Welding
(GTAW) process, for the root pass using AWS ER70S-3 with a diameter of
3mm and Ar as consumable .
The weld metals microconstituent and columnar and equiaxials grains
percentual and the granulometry and extension of the Heat Affected Zone
(HAZ) and a qualitative analysis of microconstituents present in this region
using optical and scanning electronic microscopy were performed. The
microstructural analysis was related with the weld metals Charpy impact test
results and with the welded joint Vickers microhardness profiles The results
indicated that the weld metals obtained by automatized welding process
presented the greatest Acicular Ferrite percentuais and a shorter and more
refined HZA which promoted the best results of the impact test.
