Nine-month delayed hydrogen crack (High Sierras)

Forward-referenced as Monday's story — steel component buried in snow that finally cracked nine months later because the cold Sierra environment slowed hydrogen diffusion to a near-stop. Not developed in this lecture.

But hydrogen sulfide can cause cracking — not because of sulfur, but because of the hydrogen. Here is a little bit more quantitative plot than Coe's sort of schematic plot. Where is the shortest time, and what time is it? It's just over one hour at room temperature, 20 degrees C. We live in the worst possible temperature for hydrogen cracking. If you live in the Arctic — I might tell you on Monday a story of hydrogen crack where it got buried in the snow in the High Sierras, and it lasted for nine months in the steel before it did this damage. Or you can heat it up to 100 degrees C and drive it off in a reasonable number of hours to get rid of it. Diffuse it out. Just like Sprite — you have warm Sprite, you boil your Sprite, no CO2 left. No hydrogen left either.

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