The Effect of Welding Parameters on High-Strength SMAW All-Weld-Metal — Part 2: AWS E10018-M and E12018-M

摘要

Three AWS A5.5-81 all-weld-metal test assemblies were welded, each with one of E10018-M and E12018-M type electrodes from standard production batches, varying the welding parameters, in such a way as to use high heat input and high interpass temperature (hot), medium heat input and medium interpass temperature (medium) and low heat input and low interpass temperature (cold). Mecbanical properties and metallographic studies were performed in the as-welded condition. The following results were achieved: the three all-weld-metals from E10018-M electrodes satisfied the AWS requirements, despite the fact that the measured properties varied slightly. With the E12018-M electrodes, the medium test specimen was the only one that fulfilled the AWS requirements. The cold test specimen showed a yield strength that exceeded the maximum requirement of the norm and the hot specimen did not achieve the minimal value of tensile strength. All the test specimens satisfied elongation and toughness requirements. Metallographic studies showed that as the heat input increased, the percentages of recrystallized zones increased, the grain size became larger and, in the columnar regions, there was a small increment of acicular ferrite and ferrite with second phase at the expense of primary ferrite. These results showed the E10018-M alloy to be markedly less sensitive to the variations of heat input than the E12018-M. With the E12018-M electrode, it is necessary to weld under strict control and with precise conditions, as found for E11018-M electrodes in Part 1 of this work, in which the same study was performed with the latter type of electrode.