1959 年 45 巻 5 号 p. 522-527
The optimum temperature of solution-treatment to get high stress-rupture life is 1065°C. Solution-treatment at temperature higher than 1065°C causes grain coarsening and overaging during long-time tegting, and decreases the resistance of creep rupture.
Specimens solution-treated at 1065°C have superior creep rupture life to the specimens solution-treated and aged at 750°C. Bat the life of stress-rupture testing of the formet becomes inferior to the latter in longer testing time.
The stress-rupture strength at 750°C of specimens heat-treated by H, which contains aging of 24 hours at 840°C, 16 hours at 760°C and 16 hours at 816°C is superior to other heat treatment. But at 816°C stress-ruptnre strength of specimens heat-treated by H is inferior to other heat treatment, because at higher testing temperature, heat treatment H causes overaging during stress-rupture testing.
The heat treatment B which contains water cooling after solution-treatment gives higher short-time tensile strength and stress-rupture strength than other heat treatment. This forms a contrast to Nimonic 80A on the effect of heat treatment.