Mad Mick wrote
The more I think about this, the more I'm inclined to believe that the heat build-up in the lock body is diminishing the interference fit between the plate and the body. The result of this, is the combined spring force pushing the plate out from the lock, and not the effect of steam.
This probabily correct. When the padlock is heated up the air inside the keyway will also get hot and it expands. When it is quenched the air rapidily cools and creates a small vacuum which sucks in cold water. Once cold water is inside the keyway it will cool the rest of the padlock down like the outside, when the water and air get hot again they simply expand back out the keyway. So there is no great pressure which pops the plate off.
Infact when I tried this the plate almost came off before quenching. If you were to heat the padlock on the opposite side of the plate the padlock gets hot, but due to the interface the plate does not get as hot (think of a cup of coffee and why the mug is hot and the handle is cool, BAD INTERFACE). The brass padlock expands while the plate remains cooler and thus contracted in relation.
Whay actually pushed the plate off I am not sure as when I tried this the springs were useless they were so soft that all push was lost from them. I guess it is pushed off by a bad contact between the two parts.
Just my thoughts.
Jimmy
