fire damage to gears etc

[tapper]

If a machine is in a fire, (catches on fire)is there an
easy way to check gears etc. ie: suppose an excavator
catches on fire and burns. Some of the aluminum parts
external will melt, (alternator etc) but the piston inside
the engine will not melt. The planetary gearbox to make the machine swing costs upward of $30k. It is common to
throw it out and not salvage any of it. Would this really
be no good? How can you check?
thanks.

 

[Metalguy]

I'd check the condition of the gear oil first, and if it burned then I'd check the gear hardness with a small portable hardness tester. Then, if it was ok, I'd party.

 

[metallurgymike]

I would also do some insitu metallography to check the structure of the steel, it goes hand in hand with the portable hardness testing.