Avaliação da variação do ciclo térmico na soldagem de aços alta resistência e baixa liga (ARBL).

Abstract

In this work were determined, by the direct method "IN SITU", the maximum temperatures (Tmax.) and cooling time values ​​between 800 ° and 500 ° C (Ats / 5) in different regions of the thermally affected zone (ZTA) of joints welded high strength and low alloy steels (ARBL), varying the welding parameters, and then comparing the values ​​of this welding variable. thermal cycle obtained experimentally with those obtained through theoretical expression of heat flux using the specific heat value of the metal different temperatures, the effects of the variation of Ats / s values ​​on microstructure and hardness in weld metals and regions coarse grains and fine grains from the thermally affected zone of joints soldered under different welding energies and temperatures of preheating (To). For this purpose a data acquisition system was used with thermocouples located at different ZTA locations of the joints welded by Electric Arc with Coated Electrode and Electric Arc with Wire process Tubular, with preheats of 100 ° C and 200 ° C. The obtained results indicated significant differences between theoretical and experimental values ​​of To and Minutes / 5 Variations in cooling time values ​​between 800 ° and 500 ° C provided by changes in welding parameters did not result in significant changes in microstructures and hardness of weld metals, however, they have brought about considerable changes in microstructure and hardness values ​​of the different regions of the ZTA.