PPRuNe Forums - Engine Overhauls and Cryogenic freezing

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Engine Overhauls and Cryogenic freezing

Found on a engine overhaul website that they do cryogenic freezing of engine parts to season the engine parts prior to assembly. Seems that many other industries do it including the drag racers and NASA.

But...does it actualy work. Does spending a barrowful of $ give you a more long lived and reliable engine, and thats on top of the cost of blueprinting.

Victor Aviation Service, Inc.

Short answer - a definite maybe

Slightly longer answer is that there is no theory like Newtons Laws which apply to alloying or heat treatment of steel, everything is based on observation and testing. A given property can be improved by a bit more/less of alloy element x, faster/slower cooling etc etc up to the point when it doesn't or degrades the property.

The general principle of heat to austenize, quench to martensite and temper are the same (leaving aside austempering, martempering and maraging) but all the details (eg TTT curves) for heat treatment of a given alloy is purely empirical based on tests of that alloy.

The principle of cryogenic quenching is that normal quenching does not fully convert all the austenite to martensite while cryogenic treatment after quenching (temp below the knee of the TTT curve) will convert more. For some steels this has benefits, others no and in most cases we don't know.

Long answer would cause bandwidth problems for PPRune

Hey Deaf...good post...haven't heard those terms in twenty years....memories:)

Excellent. My supply of snake oil is almost out.

FRQ CB