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Bazza

Cryogenic Hardening

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heard the term "Cryogenic hardening " today

in relation to engines !

evidently can transform standard parts into rock hard parts

would eliviate swapping to forged parts :o

any one know anymore

mark?

mat?

robin?

or anyone else :D

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sound slike bullcrap to me...

google is you friend

Cryogenics, or deep freezing is done to make sure there is no retained Austenite during quenching. When steel is at the hardening temperature, there is a solid solution of Carbon and Iron, known as Austenite. The amount of Martensite formed at quenching is a function of the lowest temperature encountered. At any given temperature of quenching there is a certain amount of Martensite and the balance is untransformed Austenite. This untransformed austenite is very brittle and can cause loss of strength or hardness, dimensional instability, or cracking.

Quenches are usually done to room temperature. Most medium carbon steels and low alloy steels undergo transformation to 100 % Martensite at room temperature. However, high carbon and high alloy steels have retained Austenite at room temperature. To eliminate retained Austenite, the temperature has to be lowered.

In Cryogenic treatment the material is subject to deep freeze temperatures of as low as -185°C (-301°F), but usually -75°C (-103°F) is sufficient. The Austenite is unstable at this temperature, and the whole structures becomes Martensite. This is the reason to use Cryogenic treatment.

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its an old process

been around many years

has been proven

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sorry didnt mean its bullcrap, that was before i googled it,, forgot to remove the sentence...

i knew about hardening usin the usual method of heat and quenching, but couldnt relate cyrogenics to it as all i had in my head was frozen people ...lol.... seems obviouse now to use super cold shizzle.

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This takes me back to College days when I did a bit of Metalurgy.

IIRC the actual process of forging has an effect in the crystaline structure of the metal making it more resistant to shear in the critcal planes of the component. As all materials are at their weakest in shear the forging process is more important than the actual hardness of the metal.

Could be wrong though as it was a long time ago :lol:

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to be honest, it sounds like it will make the metal more brittle... not good...

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basically nasa discovered this idea when the shuttle returned,because the parts had been subjected to the freezing process in outer space and heated up radiply on re-entry,they found all parts were harder and stronger than when first built so now pre do it to all the parts on the space shuttle,some but not all race teams in the US now use the same process as its been pasted down,even farm equipement uses the same idea.

The idea: freeze any engine part i.e pistons/rods/crank/nuts/bolts ect to around -300 for 20 or so hours quickly remove and warm very rapid to +300,once the process has been completed twice you have a very strong/hard engine part!

Things like cranks/pistons/rods the US are claiming upto 75% increase in strength and durability meaning they can use more stock parts without reliability issues

evidently it has been carried out on an evo in this country

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I'll speak to Kamelia...she has a degree in Metallurgy so may shed some light on the matter in hand...

I was told if you polish the casting marks of rods etc you add strength to them :blink:

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We have a sub contractor that does it for us Barrie. Can arrange it if needed.

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We have a sub contractor that does it for us Barrie. Can arrange it if needed.

to be honest , yesterday was the first i had heard off it, being nosey i wanted to know more :D

are the claims of a stronger engine without the use of forged componments true

evidently it can be done fairly cheaply

what is your opinion on it Mark

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basically nasa discovered this idea when the shuttle returned,because the parts had been subjected to the freezing process in outer space and heated up radiply on re-entry,they found all parts were harder and stronger than when first built so now pre do it to all the parts on the space shuttle,some but not all race teams in the US now use the same process as its been pasted down,even farm equipement uses the same idea.

The idea: freeze any engine part i.e pistons/rods/crank/nuts/bolts ect to around -300 for 20 or so hours quickly remove and warm very rapid to +300,once the process has been completed twice you have a very strong/hard engine part!

Things like cranks/pistons/rods the US are claiming upto 75% increase in strength and durability meaning they can use more stock parts without reliability issues

evidently it has been carried out on an evo in this country

Sounds like a bit of web-lore to me :blink: The usual steels used in engine and transmission parts are forged and manufactured in low alloy steel, typical AISI 4340 which has very good hardenability through normal heat treat and quenching operations, especially with the small cross sections involved. 4340 typically has a UTS of around 200 KSI in the full heat treated condition so most parts are rough machined in the annealed condition before final machining in the final HT condition. These parts finish in a more or less fully martensitic structure.

Critical parts like conrods and crankshafts can also be shot-peened to remove any stress raisers and further mechanically work the surface (polishing removes stress raisers, but doesn't condition the surface).

This steel is also typically used in other high strength applications, e.g. aircraft landing gear.

Freezing to cryongenic temperatures and warming of low alloy steel let alone higher alloyed steels, would also cause severe surface cracking...something you defo wouldn't want....and you cannot heat treat finished components without a real risk of distortion of the final dimensions...

I've no doubt the extreme conditions in racing engines may need higher strength materials, but the higher loading dictates that the material needs to be not only stronger, but also lighter, so the natural alternative to low alloy steel would be titanium- typically 6AL4V. :whistling:

...and where has anyone seen steel pistons except for brake calipers?????

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We have a sub contractor that does it for us Barrie. Can arrange it if needed.

to be honest , yesterday was the first i had heard off it, being nosey i wanted to know more :D

are the claims of a stronger engine without the use of forged componments true

evidently it can be done fairly cheaply

what is your opinion on it Mark

all Im going to say, in this world - you never get something for nothing... :winky:

(and im not talking cost here - im actually saying there will be a trade-off of some sort just because thats the way the world works)

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all Im going to say, in this world - you never get something for nothing... :winky:

(and im not talking cost here - im actually saying there will be a trade-off of some sort just because thats the way the world works)

you sceptic Ian

love and friendships cost nothing :lol:

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all Im going to say, in this world - you never get something for nothing... :winky:

(and im not talking cost here - im actually saying there will be a trade-off of some sort just because thats the way the world works)

you sceptic Ian

love and friendships cost nothing :lol:

really?

I find all my friendships cost time - which is a valuable asset to me :P :tomato:

as for love... you must be having a laugh... blooming expensive if you ask me! :winky:

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all Im going to say, in this world - you never get something for nothing... :winky:

(and im not talking cost here - im actually saying there will be a trade-off of some sort just because thats the way the world works)

you sceptic Ian

love and friendships cost nothing :lol:

really?

I find all my friendships cost time - which is a valuable asset to me :P :tomato:

as for love... you must be having a laugh... blooming expensive if you ask me! :winky:

you still paying for it :o have a word with Aido, he knows some really cheap ones :winky:

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