OXIDATION BEHAVIOR OF WELDED AND BASE METAL UNS NO6025

摘要

The oxidation behavior of specimens containing tungsten inert gas welds of UNS NO6025 (NiCrFeAlY) was investigated in air for up to 5,000h at 900 sec-1000 deg C and 1,000h at 1100 sec-1200 deg C. In general, the microstructure was very homogeneous in the weld with smaller carbides and the A203 intemal oxidation penetrations were similar or smaller compared to those formed in the base metal. Oxidation rates are low for NO6025 in this temperature range compared to other commercial chromia- forming alloys. As is typical for most alloys above 1000 deg C, scale spallation becomes more significant and leads to depletion of A1 and Cr in the metal substrate beneath the oxide. The depletion was observed to occur to a similar extent in both the weld and base metal for N06025. The maximum intemal oxidation depth of the base metal at 900" and 1100 deg C was lower than several other commercial Ni-base alloys.