Tow Missile Stress Corrosion Study (Ring Specimens)
ARMY LAB COMMAND WATERTOWN MA MATERIAL TECHNOLOGY LAB
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This report addresses a stress corrosion study on 300 grade, 18 cobalt containing maraging steel C-300 and 250 grade, cobalt-free maraging steel T-250 TOW missile motor cases. In the early 1980s cobalt became a strategic element which led to the use of T-250 in place of C-300 in this missile system. This report attempts to establish relative differences in stress corrosion susceptibility between the two materials in the component fabricated condition. The specimens used in this study were ring-type specimens, which were machined from along the length of the actual rocket motor cases. Each specimen was notched, precracked, and tested in a salt water environment. Load versus time-to-failure data was obtained. Also investigated was the possible effects of residual stress on the load versus time-to-failure data. Results indicate significant scatter in the data, which could be attributed to the residual stresses along the length of the rocket cases. There was no significant difference in time-to-failure between the two steels.
- Properties of Metals and Alloys
- Rocket Engines