I have read a couple of books on boiler, but could not find an answer to a question. I hope to find the answer in this forum.
All books describe that scale, corrosion and embrittlement cause weakening of boiler tubes. This could cause cracks, leaks & rupture, and boiler failure. However the explanations are not very detailed.
I am wondering when cracks leads to a boiler failure / explosion and when not?
I understand the flash steam" mechanism: pressure drops when there is a rupture in the boiler. Water changes to steam and re-pressurize the boiler (1 to 1700), and it causes explosion.
What is not clear to me is the following: when do crack in tube lead to this flash steam? and when not? when does it cause explosion? Apparently not every crack leads to an explosion.
Does it depend on the size of the crack? Does it depend on the location of the crack (wall furnace vs boiler tube)?
Many thanks in advance.