Cryogenics

[4door_Sleeper]

Would this be a good time to remind readers of that winning edge Peter Perfect got from using a fuel polariser?

Sometimes the winning edge is all in the mind, if you think you have an edge then you think you can push the car just a little bit harder.

I'm not sure that cryogenically treating engine parts fits into this category, but it somehow seemed worth mentioning

[GTRgeoff]

Sure it is. A mag I read from the UK, Race Car Engineering, is very big on the team engineers role in convincing the driver of his ability to win. Any edge is worth the effort. Seems there are real benefits to cryo and drivers believing in reliability in their cars are more likely to push hard for a win.

[Warpspeed]

Ha-ha Carroll Smith the famous race car engineer once said, "you can tune any part of the car, but usually the most worthwhile part to tune is the drivers head".

Also psyching out and demoralising the opposition is a big part of it too.

Have you heard the rumor that a certain well known race team are now using some special paint that cuts air resistance by 90% ?

All jolly good fun, but frowned upon by the professional engineer or scientist.

[GTRgeoff]

That's why teams have managers

A good one I recall was with personal weapons in defence forces. The west usually classified theirs as accurate to 400m so the Soviet weapons were then 'upgraded' to 500m.

As far as cutting air resistance by 90% goes, well Messers Bernoulli and Reynolds will be turning in their graves:D

[Warpspeed]

Ah yes, and there is the thing that you can install on the end of your exhaust pipe that costs $39.99 and increases power "UP TO" xx %

Definitely true, as it was tested by a well known world famous racing driver, whose name now escapes me.

[go_nuts]

Can you cyro some used metal bits or it has to be new in order to get the benefits?

[GTRgeoff]

Ah yes, installing that turbo whistle was just as good as putting the hair dryer on.

Fortunately though there appear to be some very real benefits to cryo treatment. Might be worth investing in a cryo unit to prolong the lives of some of the bang sticks.

[GTRgeoff]

Sb as long as it is still within spec for continued use there should be no reason not to. Wish I had learnt of this earlier to treat the internals before rebuild.

[go_nuts]

Thanks Geoff, looks like I might pull the rotors and pads off and get it treated. Some yanks swears by treating the pads and rotors, I am bit of a cynic so I'd go out and try to prove my point.

[Merli]

I noted recently that you complained of the forum getting a bit hostile, with no friendly rivalry. Perhaps you could make an attempt to do your own bit to reinstate the friendliness on the forum, for the good of all.

There was no swing from friendly rivalry to hostility in this case, like I was commenting on in the other instances. It was a simple case of you beating your own chest without any prompting.... Your credibility wasn't questioned, you just created your own chance to blow your own horn, and I'm sorry............ but it sounded ridiculous.

Hostility from me to you ends here

[oh to dream]

if cryogenically treating a metal means that the stress is absorbed by a greater surface area (or the whole), would this mean that the teeth on gears could benefit from this kind of treatment? and would this mean that the shaft they are connected to would absorb some of the stress?

just my 2c, i thought raising this point may be of use to some ppl.

[GTR-NUTTER]

what are the know benifits of this, for instance can i run higher boost higher rpm ect

i am real interested in this treatment

K

[Sydneykid]

Good discussion guys, I have picked up a few tips from most of the posts. I have only had one experience with cryo treatment and that was a pair of RB26 camshafts. They were used and slightly marked on several lobes when they arrived. This looked to have been an oil feed problem as the hardness test came back OK. So we lightly machined the lobes to removed the marks and then sent the camshafts off to be cryo'd, as an alternative to heat treating them. They have been in the car for nearly a year now and over the Xmas off season, I will pull them out and have a close look at the lobes to see what the results are. But so far they look fine, with no valve clearance adjustments necessary (that's a good sign).

I would say that if you are loooking at adding maybe 10% to the horsepower limit of the components, then maybe cryo is worth looking at for new rods, cranks and cast pistons. If you are using well used components I think it probably would be a waste of time and money. They will have been hot and colds thousands of times and consequently any stresses will be long relieved.

Ditto engine blocks, although boring them would be something to consider, maybe the metallurgists in the group can add to my thoughts........

[Warpspeed]

Can you cyro some used metal bits or it has to be new in order to get the benefits?

Metallurgy is definitely not my field, but from what I have read, parts that have already begun to suffer from metal fatigue and have microscopic cracks are not going to be restored to original strength or condition by heat treating or any other process.

While cryo might be good on fresh new parts, at the very least I would get the old parts crack tested first.

I have often wondered at the wisdom of specialist heat treatment of brake discs. You put the thing in an oven and very carefully control the temperature profile over hours or days to get some particular change in the metallurgical grain structure. You then bolt it onto a race car and put it through many more pretty extreme and uncontrolled heat cycles.

I am just wondering how that disc can possibly remember that original "good" heat treatment, and how further "race track treatments" can have no possible further effect on it ? Yet people pay to have this done, and others are very willing to take their money to do it.

It pays to be a bit cynical about some things. If some expert is selling some special secret treatment that he will not discuss, to make your race car parts better, I would be a bit skeptical, particularly if it is an expensive process.

If it is something like extrude honing, where you can see the results, but do not really need to know about the exact secret process to do it, that is fair enough. But when the parts come back looking exactly the same, I would be a bit more curious as to the exact process.

Shot peening is another "mystery", while it has some definite benefits if carried out properly on suitable parts in the correct controlled manner.

But just hitting every steel part with the shop sand blaster and saying they have been shot peened, and must now be a lot stronger is not going to get you very far.

[GTRgeoff]

There was no swing from friendly rivalry to hostility in this case, like I was commenting on in the other instances. It was a simple case of you beating your own chest without any prompting.... Your credibility wasn't questioned, you just created your own chance to blow your own horn, and I'm sorry............ but it sounded ridiculous.

Hostility from me to you ends here

As you say, but in the environment I work in, such behavior is considered somewhat mandatory. Anyway a PM would suffice next time I'm getting carried away. I have no hard feelings, the skin is pretty thick so Lets hope we get a chance to play together on the track sometime as I understand your GTR is set up pretty nice.

Back on topic, from what I have read I understand that this process really only has benefits for high carbon steels of the cast and forged variety (on the topic of ferrous based products), and accomodates precipitation to martensite from austenite which is a very brittle but hard structure. To achieve an austenite structure (which is hard but also tough) I recall a need to heat to 900+degC (yellow to almost white?)and quench in oil or water, and most discs will not reach this would they? To then transform to martensite takes a lengthy reheat to about 400degC (cherry red?) and air quenching, so some of the on car heat cycling would develop this naturally (also a clear message to continue driving to cool steadily yet rapidly in air as allowing too slow cooling like pulling into the pits straight away will allow cementite formation which makes the brakes feel like they are warped due to uneven wear). Sorry if I'm a bit fuzzy but I dont have a TTT (time temperature transfomation) chart in front of me.

The last link I posted was clear though on cryo treating at any stage of the life cycle. Need to read more.

[browny]

Two excerpts from a discussion on PF:

As a metallurgist (23 years), I found most of the above interesting and, at times, amusing (sorry guys  )

Cryogenic treatment has been around in the aircraft industry for decades - and it does work, but would be of debatable value for anything but (very) high performance car parts. The easist way I can explain it is this:

Keeping a compex subject simple...when steel is heat-treated it is usual to soak above the austenite phase transition temperature. Subsequent quenching 'transforms' the austenite to martensite. The steel is then usually tempered to the appropriate hardness/toughness. BUT, because we don't live in an ideal world, at the time of quenching, all of the austenite is invariably not 'transformed' to martensite - there is always residual austenite, the amount will vary dependant on a HUGE range of factors.

This small amount of residual austenite contributes little to the strength of the steel (relative to the martensite), so is 'undesirable', if you will. However it is also unstable or 'metastable', since it 'wants' to 'transform' martensite. All that is required is something to 'push it over the edge' as it were, and this is where cryogenic treatment comes in - by lowering the temperature of the steel sufficiently, the residual austenite is transformed and the mechanical properties of the steel is improved. [and, yes, once transformed it stays transformed even when the steel returns to room temp]

[as an aside I would note that 'martensite' is actually a metallographic artefact - it has exactly the same crystallographic form as austenite, but 'distorted' due to the presence of carbon]

'Toughness' is the resistance of a material to crack growth, by transforming residual austenite to martensite the mechanical properties of the steel are improved and consequently so should the toughness (but that's a HUGE generalisation).

The subject of heat-treatable aluminium alloys is a whole different ball game.

Ideally you would want to quench from the austenite phase to the lowest temp possible to acheive full transformation, but, in practice, this is impractical because it would invariably lead to cracking of the component (esp to LN temps: -196C or thereabouts). Usually a compromise is acheived in consideration of the particular steels TTT diagram (Time-Temperature-Transformation), it's thickness, geometry, etc.

As-quenched martensite is very brittle and hard, and steels are rarely used in that form. Subsequent tempering produces a more acceptable structure - but still containing some austenite. Cryogenic treatment 'transforms' the remaining austenite to 'hard' martensite which is more beneficial than leaving it as austenite - plus what is 'transformed' remains contstrained by the surrounding structure which actually has beneficial effects in terms of residual stresses, etc.

Cryogenic treatment is invariably applied to the final product, but usually before final machining, esp in high precision components (read: aircraft parts) because minor dimensional changes can occur because of the process.

I would be highly sceptical about massive gains in material props because of this treatment alone, esp with car parts. OTOH, weight/performance gains are critical in aircraft parts, particularly military - and this is where the process has been used very successfully.

The bottom line: for a road going performance car - forget it, but OTOH I'm sure the F1 people are using it

The whole thread is here:

http://board.performanceforums.com/forums/...&highlight=cryo

[Chef_32]

4door_Sleeper... sounds very much like what we learn last year in basic Quantum Mechanics. They use a series of lasers to cool atoms to such small temperatures. Very interesting stuff if i could be bothered going to class.

and

hahahaha BUSTER got his penis pleened.....