STUDIES ON MECHANICAL PROPERTIES AT ELEVATED TEMPERATURE OF TIMKEN 16-25-6 (I)

Abstract

The authors studied the influence of the time of solution-treatment on the mechanical properties at 650°C with Timken alloys. Test pieces of Timken alloys were solution-treated for 1 hour and 10 hours before "hot-cold working" or age-hardening. The results were as follows.
(1) Creep resistance and yield strength at 650°C increased by the long-time solution- treatment before "hot-cold working" or age-hardening, because the precipitate were finelv distributed and the precipitation-hardening during testing at 650°C became prominent.
(2) In the case of the long-time solution-treatment, ductility of creep rupture testing decreased than the case of short-time solution-treatment, because the precipitation during the testilng was more prominent in the former case than in the latter case. On the contrary, the ductility of the short-time tensile test, in which precipitation during testing was slighter than creep rupture test, was smaller in the case of short-time solution. treatment than long-time solution-treatment. It was because of advanced diffusion and homogenizing by the long.time solution-treatment.
(3) Effect of long-time solution-treatment became prominent by precipitation-hardening during-esting, so that its effect was more prominent in "hot-cold-worked" condition than in age-hardened condition, and in the long-time and high-temperature testing than in the shorttime or room-temperature testing.