The objective of this work was to evaluate the heat affected zone characteristics and weld metals microstructure and mechanical properties of API 5L X80 steel welded joints, obtained for four different welding procedures using manual and automated processes. 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 and Ar25%CO2 as consumable and mechanized Gas Tungsten Arc Welding (GTAW) process, for the root pass using AWS ER70S-3 and Ar as consumable .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 weld metals obtained by automatized welding process presented a shorter and more refined heat affected zone and a weld metal with greatest Acicular Ferrite percentiles which promoted the best results of the impact test.
API 5L X80 steel; automated welding; microstructure; weld metal; impact resistance; microhardness
