2007-01-20 09:24:35 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
a single hydrogen atom is small enough to pass through many materials- including solid steel. However, when two hydrogens "bump into each other" inside a solid, the two hydrogens form H2 which then is too large of a molecule to pass through the solid. The trapped H2 changes the properties of the local metallurgy and "embrittles" the local area.
This usually happens when there is an abundance of Hydrogen in the area- for example the decay of NaOH caustic or when welding without first removing all the moisture and humidity in the area. PReheating is a good practice to specifiy prior to welding and an inert blanket (argon or nitrogen) over the weld will keep out humidity.
2007-01-20 10:20:11 · answer #1 · answered by MrWiz 4 · 0⤊ 0⤋
As usual Wikipedia spills the beans on it
2007-01-20 09:27:50 · answer #2 · answered by Anonymous · 0⤊ 0⤋