Abstract
The authors studied the lomg-time-creep-rupture properties at 600, 650 & 700°C and short-time-tensile-test properties at room and elevated temperatures of Timken 16-25-6 at the state of "hot-cold" working (hot cold worked at 700°C and 20% of reduction from as-forged, condition), as solution treated, and as precipitation hardened.
The results were as follows:
1. "Hot-cold" worked specimens had higher strength at the temperature below 700°C than in the other heat treated condition anq the ductility was also sufficient for practical use.
But the effect of strain hardening decreased along with the increase of temperature and testing time, then the strength of "hot cold" worked specimens approaches to that of the other kind of heat treatment.
2. The strength increased and reversely the ductility decreased by precipitation hardening during the elevated temperature testing. So, the precipitation-hardened specimens had lower strength and higher ductility than solution-treated specimens. This phenomenon was evident when specimens were tested at the testing temperature and time of which the rate of precipitation hardening was great. Therefore this effect was not clear in short-time-tensile-tests and long-time or high-tempesature creep rupture tests.
