Stress-Controlled Notched LCF Properties (Hot-Rolled Rings)
The following test results were generated from hot-rolled and fully heat-treated rings destined for actual gas turbine engine part applications. Testing was performed in the tangential direction utilizing a round test bar geometry with a double notch design (Kt=2.18). Loading was uniaxial cycling with an R-ratio of 0.05 stress and a cycle frequency of 20 cpm (0.33 Hz).
| Maximum Stress |
Cycles to Failure at 1200°F (650°C), NF |
| ksi |
MPa |
242® |
909 |
| 110 |
760 |
845 |
2,835 |
| 100 |
690 |
12,220 |
22,568 |
| 95 |
655 |
32,587 |
13,796 |
| 90 |
620 |
76,763 |
55,679; 40,525 |
| 85 |
585 |
297,848 |
47,707; 43,701 |
| 80 |
550 |
304,116* |
129,573** |
* No crack observed at 198,030 cycles. 8 mil (200μm) crack observed at 200,000 cycles.
**No crack observed at 45,800 cycles. 8 mil (200μm) crack observed at 47,770 cycles.