THE EFFECT OF CARBON IN E7024 SMAW ELECTRODE ALL WELD METAL

Four rutile electrodes with iron powder in the coating, E7024 type, adequate for manual and gravity welding, were produced in such a way as to obtain nominal carbon contents of 0.03, 0.06, 0.10 and 0.13% in the deposited metals, while the rest of the alloying elements remained constant. The all-weld-metal mechanical properties were evaluated according to AWS requirements, and it was found, as a general tendency, that as the carbon content increased, the tensile and yield strengths increased and the ductility and toughness decreased. It is possible to obtain a Grade 3 weld metal (with minimum 47 J at -20 degrees C) with up to 0.10% carbon. Metallographic studies with the optical microscope and hardness measures were also carried out.