The age-hardening phenomena of Timken 16-25-6, the heat-resisting alloy for gas turbine material, was studied by determination of hardness and microstructure. There were three different per centage components in the specimens. The contents of carbon were of two kinds, 0.20% and 0.06%. The content of molybdemium were of three kinds, 6%, 3%, and none. Ni, Cr Si and Fe (balance) were kept unchanged.
The materials were melted by high-frequency furnace and then hot forged to bar. The solutiontreatment were done at 1150°C, for 1 hour. Then the materials were aged at high temperature, (700, 800, and 900°C) from 15 minutes to 50 hours. 6% Mo specimens, which were either of 0.2%C or 0.06%C, had two peaks of hardness, and the latter was harder after 50 hour aging, especially at 800°C.
It seemed that first peak of hardness mainly depended on some carbon condition, and the second peak of hardness mainly depended on some molybdemium condition. 3% Mo specimens were not as hard even after 50 hours aging, as compared with the 6% Mo specimens. When the specimens were aged, precipitation in microstructure was observed simultaneously. The specimens containing no Mo were not aged ever at high temperature, either in hardness or microstructure.