UKC

I am specificaly after a response from metal workers, i know a reasonable amount about steel, but i think i must be missing something realy obvious as i cant see any reason against this at first glance...

If i were to case harden the tip of my ice axe it would resist wear a lot better that it does at the moment.

Case hardeneing is not particularly expensive.

As the axe wouldnt be hardened down its entire length, only the first 10mm or so, it would still flex, torque and behave the same.

As case hardening only hardens to a few microns the tip wouldnt become brittle and shatter when hit on rock like with high carbon or hss.

SOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO

Q.Why dont the manufacturers do it?
(A.cos then they couldnt sell spare picks?)

Q.Can anyone think of any reasons why I cant do it to my pick now?

mat

In reply to matnoo:
Not a metallurgist, but I can give you a reasonably educated guess.
The heat-treatment of high-carbon steel (old style)was to heat it to cherry-red and quench it; this will leave it dead hard. You then temper that hardness by heating it to the temperature appropriate for the level of hardness you want and quench it again. Depending on the temperature of the second heating you will end up somewhere in the continuum between soft and malleable, and dead hard and brittle. It's probably a bit different with modern alloy steels but the principles are likely the same.

The heating you'll have to do to case-harden the tip will almost certainly destroy the temper and leave the rest of the pick soft which will let it to bend and twist as soon as you put any load on it. I'd imagine that manufacturers spend a lot of resources achieving the optimum temper, so I'd recommend you leave it alone. You could experiment with an old one though.

In reply to matnoo: As said by Mike Swann, heating a pick will alter the temper of the steel making it softer and much less resilient, this is the main reason you should never sharpen axes or crampons using a power-tool such as a bench-grinder. If you case-hardened the tip of your pick, the tip would be really hard and so would be more resilient if you whacked it against a rock but the rest of the pick would be much more fragile and will get fatigued more easily and so would be a great deal more likely to fail. Also, teh harder tip would transmit vibration more increasing the load on the steel in the rest of the pick again leading to faster wear and a higher level of fatigue.

To put it simply, case hardening or any other process which significantly heats the metal of an axe or crampon will shorten it's life and can lead to premature and catastrophic failure and so is generally not a particularly good idea.

Jon

In reply to matnoo:

If only life were that simple, we could all tailor our tools in the kitchen

Although I am a metallurgist I am not a heat treatment expert but I think I know enough about the basics.

Case hardening is a process used for certain low carbon steels that do not respond to conventional quench and tempering processes because the carbon content is low. So the steel is heated to red hot and dipped into a carbon such that the surface absorbs carbon. This is done several times to get the carbon rich layer to be about 1mm thick. The steel can then be heat treated in the usual manner to produce a hard surface zone. This may not be much use for axes as the steels used are usually low alloy steels that have already been heat treated.

The basics of heat treating are pretty much as described Mike and are carefully designed to give the desired microstructure and hence properties. These properties will always be a compromise on something like an ice tool given the abuse they are going to get. One needs a combination of strength, impact resistance, wear, ductility (elongation or strain to failure) and toughness (resistance to behaving like a snapping carrot). To a great extent these properties are mutually exclusive; high strength steels are p*ss easy to make but they won't have good toughness and vice versa. So to get the balance right takes a good deal of thought relating to composition and heat treatment regime.

Also one has to be careful with a hardened outer zone and it's relation to the softer inner zone. If this is not done correctly there is a risk of crack initiation in the outer zone when it gets cold and is whacked into the side of Scotland. If this happens there is no guarantee that the crack will not propagate into the soft zone even though it is apparently much tougher. The consequences of which should be very obvious.

One final thought, having carburized the tip how are you going to heat it up again then quech and temper it without screwing up the original heat treatment on the rest of the blade (assuming it hasn't been f*cked up by your previous tinkering to get the carbon into it in the first place)?

Just to be clear, I don't think this is a very good DIY idea.

In reply to Horse:

I'd agree with all of the above. I'd add though that case hardening is normally done in a carburizing (I think that's the word) furnace in which there is a carbon rich atmosphere which can be carefully controlled.

Case hardening normally extends a lot more than a few microns - somewhere nearer a millimeter would be a better guess. That means the hard and brittle layer would extend quite a way through the thickness of the pick.

The reason I remember all this shit is that many years ago I got some hollow dowels case hardened to improve their wear resistance. The trouble was that they shattered when you dropped them on the floor.

By the way, my other half has just asked why you are called Horse.

In reply to Removed User:
Correct
Think that demonstrates to point rather well!!


It's on my profile.

In reply to matnoo: Why don't you just aim more carefully Mat?

In reply to matnoo:

Not a metallurgist but a mechanical engineer specialising in wear.

I won't repeat what the others have said except to say don't do it and reiterate that it's just not that simple. One thing I will add is that by heating the tip (to case harden it) you will be effectively removing all the heat treatments that the manufacturer has applied (the steel will revert back to austenite crystal structure).

From a purely wear point of view, by hardening (as in hardness, not stiffness) the surface, yes you might improve the wear properties. However, I would think that over the life of a tool it would be minimal, if noticeable at all.

Also, the harder steel (likely containing martensite I'd guess) will be much more brittle, so it will fracture rather than bend.

In reply to matnoo:
I know F**k all about case hardening but I do know that if you try tinkering with the rear brakes of a new VW Golf that it will leave you with a f**ked car that even trained mechanics can't fix.
There's an allegory in there somewhere.

In reply to matnoo:

This whole debate about hardness and toughness (having trained in Mech. Engineering I understand what some of you guys are saying) begs a couple of questions...

1. We have an abundance of new bonding technologies that work in a wide range of temperatures. Am I right in saying that Rover's K-Series engines are partially glued together? Why couldn't we have composite picks - most of the pick being tough, with a bonded in tip being wear resistant?

2. What about other materials for picks? Plastics like metals are pretty susceptible to temperature change and tend to become more brittle in lower temperatures, but surely there must be materials other than steel based alloys that would lend themselves to a good thrashing on rock and ice.

In reply to Armchair:

Interesting ideas, I suspect steel wins out for three reasons:

1) The huge versatility of the material that allows us to tailor it to just about any application we want. At least where weight is not a big issue.
2) It is comparatively cheap even at the more specialist end of the market.
3) It has a proven and long track record.

It is incorrect to state that metals are susceptible to temperature change this is not always the case, for example austenitic stainless steels don't change at all down to cryogenic temperatures. Certainly it isn't so for steel: provided the correct type is used. The trick is to use a steel (or indeed plastic or composite) which will not undergo some change at the likely range of temperatures in which it will be used.

In reply to Armchair:


Not really.

Plastics just aren't hard or stiff enough to cut the mustard.

It's perhaps conceiveable to have a carbon fibre pick with a ceramic insert at the point but I wouldn't want to climb on it. To many interfaces to break compared to a nice homogeneuos piece of steel.

Steel has a very good blend of hardness, toughness, wear resistance, fatigue resistance, strength, formability and density. Don't forget that mass is also important.

There may be other more exotic metals out there that might perform better but nothing I can think of would work better.

Good question though. Worthy of some thought.

In reply to Removed User:
I think that most of the exotic metals and alloys that are currently available suffer from two drawbacks wrt to winter tools:

1) They don't have the sfiffness, things like Titanium, Aluminium, Magnesium alloys etc are not stiff but in other application than tools this can be overcome by using a stiffer shape for the component.
2) As you rightly say mass is important and most exotic alloys have been developed for applications like aerospace where mass is a distinctly undesirable.

In reply to Removed User:


God, all the geeks are coming out of the woodwork here. I cant resist.... Case 'carburizing', is done as Eric describes yes. However, there are other ways of case 'hardening' - ones that are less available to DIY 'tinkering'. Thats assuming you really want to try - and I agree entirely with Horse, here i.e. dont bother - e.g. induction hardening and plasma nitriding (or is that 'nitriling', I cant remember - Horse?).

With induction hardening it is difficult to get a case depth of much less than about 1mm. With carburizing, depending on the steel, it should be possible to get quite a shallow case depth (much less than 1mm).

Apart from all the complexities of the hardening process you have tempering and stress relieving to consider - both equally as important.

Basically its a science in its own right... Probably one you dont want to bother with.

Oh and I'm a bearing (boring ?) engineer, in case you ask.

In reply to Graham B:

And of course there's a possible failure mode of the hard layer cracking off the softer layer...

In reply to Removed User:

How about using an amorphous metal? Incredibly hard, very strong, tough, high corrosion resistance... sounds almost ideal - shame they're a little expensive at the moment though!

Stuart

In reply to Removed User: What was the legendary aermet BD picks made of? They were reputed to be extra hard.

In reply to Horse:



It's interesting you should say this, as one of the first jobs I was given as an apprentice was testing various steel alloys for brittleness. It was amazing how the brittleness could change over a small temperature range, testing was done between -15 and 80 degrees C, with wide changes in the crystalline structure.

In reply to Armchair:

You were testing steels that start in a ductile condition at the higher temperature and then change at a lower temperature. The temperature (or more likely the range)at which this occurs is the ductile brittle transition temperature. During the this transition microstructural transformation take place and this may alter the toughness of the material.

My point was that if one knows the likely service temperature extreme is likely to be, say, -15 then select a steel that remains ductile beyond that temperature, -15 isn't that cold. Which is what I thought I had said in my last post.

To whoever asked about the BD blades. I they were steel, slight guess but I would imagine they were made from Aermet 100 a proprietary steel produced by Carpenter Steels in the US. It is a heat treated martensitic steel, good toughness, strength and I would imagine very hard.

In reply to Horse:

Thanks for clearing that up,

In reply to Armchair:

I know this is completely off-topic, but I have read (can't remember where - some materials engineering mag/journal) low temperature embrittlement of steel is one of the reasons the Titanic went down. Engineers at the time were unaware of how brittle steel became near 0 degC so when the ship hit the iceberg, the resulting crack propagated much, much further than anyone expected (because the steel was thought to be ductile, not brittle), so more compartments were effected than the ship was designed to take. Not sure if this is true, but it sounds plausible.

Going back to exotic materials - one thing to remember is that although many of them have superior *specific* properties (strength, modulus, etc) steel often still comes out on top when you consider the absolute properties. fibre composite materials are not really an option because they are too susceptible to compressive failure in bending. And they are not very good at handling impact loads (low + high velocity). Another massive bonus of steel is that it is easy and cheap to work with - many exotic alloys are notoriously difficult to machine/cast/finish/polish/etc.

In reply to SimonG:

Simon the Titanic thing is interesting, it was actually mentioned on last nights Materials World on BBC R4:

http://www.bbc.co.uk/radio4/science/thematerialworld.shtml

Which has a link enabling you to listen to the programme.

The idea is not so much that fracture caused the sinking, clearly the large lump of ice was the primary cause rather that the impact cause a crack to propagate. This ran down most of one side of the vessel and allowed water into the hull by passing all the bulkheads. Thus explaining why the ship sank so quickly.

We know steel of that time was not that tough at low temperatures (like water in the N Atlantic) and if hit hard by a large object might well crack. The problem I have is why didn't the crack stop at the fist plate to plate connection?

Again the issue is not steel per se but the quality of the material used. We can now design vessles and fixed platforms to deal with things like ice hitting them because we ensure the steel is ductile under the service conditions.

In reply to Horse: very interesting discussion. Does show, to my amazement, that these fora are not entirely used by lovesick adolescents, self-regarding in-groups or obsessive political fanatics. There are also some people who actually know what they are talking about and can sustain a coherent discussion!

Re the Titanic, I was under the impression that the main problem (apart from the obvious stupidity of going far too fast for visual observation, pre-radar, in a known danger area) was trying to stear round the iceberg AND trying to slow down. If they had done one or the other (or even done nothing), the ship would have probably survived. Curious that the Titanic is now considered the paradigm of bad construction/design (which was not true), rather than diabolical seamanship, which was.

Incidentally is there a consensus that the old idea that a dropped carabiner should be discarded is an old wives tale?

I think most people are getting case hardening mixed up with tempering (or most likely high carbon steel). Case hardening is something that is done to hammer heads (well, high quality ones anyway). They are made of medium steel with a high carbon case.

Further to previous posts, the high carbon content in teh surface doenst make the item brittle (hammers dont shatter), neither can it crack off (like a crust or skin) as the case hardened part is not a seperate material, its still part of the same casting with the same crystaline structure and not prone to fracture.

The case hardened part is also not like a skin, ie its carbon content decreases to normal gradually over through its thickness.

Its a bit like reenforced concrete, the properies of concrete and steel rods individually are weak in one form or anther, composite them together and you get flexible concrete!

To case harden a hammer head, you get it malleable on the inside (able to take huge shocks) and hard on the outside (able to maintain its shape and doesnt wear). Which id say its perfect for an ice axe.

There has been some good points made, but none good enough to totally convince me that from a structural point of view, case hardening isnt a good idea...

As for the case hardening affecting the temper, could the increased surface carbon content be applied BEFORE it gets tempered, as once its turned to high carbon steel, it isnt going to release the carbon from the surface of the material unless melted down*

Selective tempering could be applied with the old method (putting it in a box filled with carbon) instead of the carbon rich gas jimbob thingy*2


Mat

* Im fairly sure the only way to lower the carbon content (by weight, and not characteistics!) is to melt it down and start again?

*2 You know what i mean.

In reply to matnoo:

Right!

You got me thinking. Spending my working hours involved with injection mouldings in the microelectronics industry has left my knowledge a little rusty but I just happened to have a textbook on the bookshelf behind me...

Case hardening is normally carried out on steels with a carbon content of about 0.15% because they will not respond to direct hardening methods.

During carburising the carbon content of the outer layer of the steel is raised to about 0.90%. How deep this layer is depends on how it is carburised and for how long. If carburising is done in a solid medium the rate of carburising starts at 0.30 mm/hr but slows down as the depth increases. Carburising can also be carried out in salt bath which is very rapid and produces a case about 0.30mm thick. The process is very rapid but there is a tendency for the case to crack. Gas carburising is used to carburise to a depth of about 1.0 mm in 4 hours.

Your point about getting a gradual change of content is correct but the problem is that the prolonged heating causes grain growth throughout the part which leads to poor toughness. Remember that a hammer is massive and subjected to compressive stress so it's probably OK not to carry out the subsequent heat treatment necessary to get a good grain structure in the core of the part.

In order to get a good strong structure a series of heat treatments and stress reliefs are carried out which result in an outer layer of martensite folowed by a zone of Troosite-sorbosite and finally pearlite/ferrite.

Or so the book says.

I think the important part is at the start. The mild steel core just isn't strong enough. If you put the pick in bending through torqueing etc the core is likely to go plastic. At that point the modulus of elsticity of the core drops and most of the bending is resited by the hard but relatively brittle outer layer. Fracture is likely and the crack will propagate through the martensite, through the core and out the other side!

If you're a mechanical engineer I subject carrying out a little stress analysis to get a better insight of the stresses involved when you put a pick into bending across it's minor axis.

I guess picks are normally made of a higher carbon steel alloyed with all sorts of other things to give the correct blens of strength and toughness. If you wanted to harden it then I reckon something more like induction hardening or nitriding would be more appropriate.

In reply to SimonK:

You may be right about the Titanic, never really got into it but the latest idea is not about why it sunk but why it sunk so quickly. A subtle distinction but it does make the world of fracture mechanics seem a bit more accessible.

The old tale about a carabiner might have held some sway in the early days but not now we use aluminium and if I had a modern steel one I wouldn't bother.

In reply to matnoo:

I can assure you I am not confusing anything and it is manifestly clear to me that there are a good few on this thread who know "reasonably more" about steel than you do.

The role of carbon is primarily that of a strengthening element. In high carbon steels one also has high yield and ultimate strength. Without heat treatment these steels will also be characterised by poor elongation (strain to failure), high hardness and the microstructure will be brittle (have poor toughness). End of story.

To improve the elongation and toughness whilst maintaining good mechanical properties the steel has to be heat treated. This would normally be achieved by quenching and controlled tempering. In structural steels the same effect can be achieved by controlled hot rolling as the deformation of rolling is also beneficial to producing a fine grained microstructure.

The high carbon content skin produced in carburizing (I don't have anything to add to Eric on this) is nothing like reinforced concrete, which is a very poor analogy. Yes the high carbon part is integral with that underneath but it will have different properties, if this were not so why bother? If this surface is less tough and a crack propagates along the interface,it may as well be a separate skin. If you don't believe this can happen I can tell you stories of 75mm plate used on bridges that has ended up as 3 plates due to fracture! It is part of my job to know about these things.

Reinforced concrete components are not weak individually but concrete will crack under tensile loads, steel doesn't. So the concrete cracks and the load is transferred to the steel. That is not what we are considering in an axe blade at all; we are considering a crack that starts in the hardened outer zone and propagates into the core.

Yes the manufacturers probably could produce an axe of the type you suggest by starting the relevant unheated blank and then designing a heat treatment process to give the finished article with the desired properties. I suspect it would not be cheap.

You certainly can't do a home made version for the reason already stated as the heating will f*ck up the existing heat treatment on the rest of the blade.

And while we are at it,you are also wrong about the carbon content remaining the same until the steel is melted down. Heating the steel and holding it at temperature could result in diffusion of carbon from the high concentration skin on the outside the low concentration on the inside. If you get the temperature wrong you will also get grain growth which will mean the affected bit will deform more easily.

I could go on but as I have already said on this thread, heat treatment of steels is a hugely complicated subject and not something us amateurs should be dabbling in. Anyway I am going to the pub know.

Eric

Good post but be careful with grain growth. It is true that tough steels have a very fined grained microstructure. However, coarse grained materials are not really brittle they tend to fail by a ductile tearing mode with lots of elongation.

In reply to Horse: yes I realise the Titanic is a bit of a diversion. The point about trying to steer and slow is that the ship sideswiped the iceberg, hence rupturing too many of its watertight compartments. Just steering round the berg they would have kept steerage way and almost certainly missed it. But I am puzzled to see how steel of any quality could have withstood the impact, notwithstanding the points about temperature effects.

It is fascinating though, but not for the usual reasons - rather because totally the wrong conclusion has been drawn about a pivotal event. The engineers and shipbuilders (and presumably metalurgists), did not do their jobs badly, they did it very well, in fact too well. So much of an advance was the ship in safety terms (lifeboats aside), over its generation, the people in charge of it thought it was "unsinkable", so got sloppy and iresponsible.

In reply to SimonK:

It is an interesting diversion generally and for personal reasons. I am off to Oz next week to do a keynote lecture at a conference on durability of materials which will concentrate on success and failures in engineering. I will be using examples from my own experience but also some headliners including: Titanic, Challenger Shuttle and the Concord crash.

All engineering successes but for differing reasons also failures, the worst arguably being the shuttle as the problem was known and ignored!

In reply to Horse: sounds extremely interesting. Any chance of a transcript of your keynote being available?

Not an engineer myself, but my climbing partner is. It is always very hard after a disaster to determine which problems should have been detected and which were just bad luck, given that almost every major project has had someone predicting disaster to it before it was completed. Rather like the comment about some group (marxist intelectuals?) predicting 6 of the last 3 stock market crashes.

In reply to Horse:


this is why im asking questions, i probably know reasonably more about plastics than you do, but i dont use "reasonably more" quotation marks when theyre not necissary.


I thought it was quite a good simple analogy, two different materials in composite, in one structure providing more desirable properties.


Which is what im asking, your answer to the origional question would be; yes, it is possible, but the cost would be too high for reasons ive stated. Thats cool.

youre just trying to make me sound stupid, if you notice i put a little * next to this point, asking about it.

sure you could.


Im not dabbling in the sacred subject of steel, im asking questions and taking and interest in it.

Mat.

In reply to matnoo: Well, from a previous job, I seemed to remember that we used to get some pretty strange hardening profiles done with a plasma process. On a 5 inch by 1/16th inch finger shaped item, we used to get full hardening at one end without affecting the temper at the other.

Can't really help any more than pointing you in that direction being an electronic engineer, and not a materials scientist..

In reply to Horse:

Sorry im being defensive, im a bit beered up and ive had a bad week. My post was a bit unnecissary. Sorry.

Points taken. What would be the cost of such a tool, are we talking about £10's £100's or £1000's here?

I think the bottom line is what the price would be when off set against the (minor) inconvenience of sharpening it every now and again.

I recon the mass produced standard is more than adequate for the job, but it doenst harm to surmise!

Mat (going to bed anticipating a hangover)

In reply to FunkyNick:
...which is one of the main benefits of induction hardening, plasma carburizing / nitriling etc - that you can heat treat locally only where you need it whilst retaining the bulk toughness elsewhere.

Matnoo:
If you want to ask questions then ask away. But dont make yourself sound like a prick by lecturing to those who are long out of college and been working in industry for years.

In reply to matnoo:

Well - for what its worth I have a degree in production engineering - although this doesn't really making me an expert metalurgist.

As to your first question - the main reason for case hardening is hardening tools that will be subject to a lot of surface abrasion.

The technique is less commonly used these days - since raw materials costs have dropped significantly vs labour costs over the past 30 years or so techniques such as induction hardening or surface coating with titanium nitride are now more commonly used.

I'm not sure a case hardend ice axe would gain you much - you want your axe to be fairly hard (but not brittle) right through since you don't want it to bend under weight.

As to your 2nd question - if you don't know what steel your pick was made from then any hardening attempts by you are a waste of time. You can only get hardening processes right by following the manufacturers recommendation vs duration, quenching etc.

Rory Chisholm

In reply to Graham B:


I AM asking questions, and havnt lectured anybody, Ive stated im ill informed to the subject and am trying to work out the answer to my origional post in my own head.

I thought it might be possible to have an interesting discussion about something without anyone resorting to name calling. What a shame.

Rory, that expalins quite a bit Ta and eric, i get what youre saying too (after the third read!).

Mat

In reply to matnoo: Amazed to find this subject on here. shame it degenerated a bit. Basically what everybody needs to rememeber is that for all the hype about modern materials there are really good reasons for iron (steel is an iron alloy) being the metal of choice for engineering purposes over several millenia. It is just so bloody excellent.

I was originally a design guy in the motor industry: long ago when we had one. Now I use an ice axe with a head made from the same steel spec that we used to use in our office for the crankshafts of turbocharged trucks. Brilliant stuff.

As for case hardening, well I used to be the gear design guy and we had some high alloy steels used for case hardened gears as well as the low-carbon specs. This was awesome stuff. However, I suspect that whatever the spec, if you kept thrashing a piece of high carbon steel with a hardness of 700 Vicker Pyramid against a piece of rock it would chip away the steel as well as the rock. A high alloy spec might mean it would chip more slowly than a lower spec steel but it would still chip: not wear away but crack and chip off. Also, it seems unlikely that case hardened surfaces would survive the bending strains on a typical pick without cracking. As one contributor has already pointed out, cracks propagate from the hard layer right through and a bit breaks off your pick.

I still like my old crankshaft steel.

In reply to JimF:

I've read this thread with interest and was amazed at the expertise lurking out there.

One thing that no one has mentioned though is hard coating (as opposed to diffusion treatments). If you want to improve your wear resistance without messing up the bulk properties of your tools, I don't see why you couldn't get them ceramic coated.

The most common coating for this sort of application is titanium nitride (the gold coloured stuff on expensive drill bits). Putting down a thin, adherent coating using physical vapour deposition can be done at domestic oven temperatures, which has little effect on the metallurgy of most alloys. The ceramic is only a few microns thick, so it has no real influence on bending etc, but can be very effective at reducing wear. As it doesn't affect the tool, when it wears off you just resharpen and recoat.

The only real downsides I can see to this are the expense and finding a company that will to do it on small numbers of tools. It's a batch process, so your tools could be put in with other pieces when there is excess capacity, assuming you could find an accommodating company.

The aesthetics of gold tools would be questionable too!

In reply to sticky:

Well there are lots of things that could be done, we could use the maraging steels we were talking about last week, we could use hardsurfacing techniques, we could use stellite. We don't and we ought to stop and think why this is so. I am not sure that we really need these fancy hardened tools but I concede the idea of gold axes that didn't easily scratch is rather appealing!

As to PVD coatings my limited knowledge of these suggests things may not be that simple. I suspect that whether or not the substrate steel is affected depends, yet again, on the thermal history of the steel in particular the finishing temperature of the final process. If this is too low then PVD coating could affect the steel properties.

In reply to Horse:
we could use stellite. We don't and we ought to stop and think why this is so. I am not sure that we really need these fancy hardened tools

Dear Horse

Stellite was used in the 70's on picks and crampons, it was used for better grip on rock. As I never rock climbed in the winter, I never need to get my tools done with stellite.

Norrie

In reply to Norrie Muir:

Dear Norrie

You must have been a very wealthy man in those days to be able to afford to have tools made from an alloy containing around >65% Cobalt and @10% Tungsten. I would have thought to a man of such wealth the replacement of conventional tools every now would have been loose change, if a little frivilous.

Horse

In reply to Horse:
You must have been a very wealthy man in those days to be able to afford to have tools made from an alloy containing around >65% Cobalt and @10% Tungsten. I would have thought to a man of such wealth the replacement of conventional tools every now would have been loose change, if a little frivilous.

Dear Horse

I do not understand the above posting, please explain it more clearly to me , so I can reply?

Norrie

In reply to Norrie Muir:

Dear Norrie

Cobalt very expensive metal. Stellite contains 60 to 70% cobalt, therefore tools expensive, therefore you must have been a rich b*stard back then.

Horse

In reply to Horse:

Dear Horse

I think you misunderstood me, I did not have it done, as I said I never heeded I done.

We did not know engineers, metallurgists or other professionals. But we knew tradesmen who could do “homers”, which did not cost anything. Yes, it would have been expensive, if one had to pay for it.

Titanium axes and deadmen were also made, but I do not know how good they were. In the shipyards anything could be made as “homers”, if one knew the right person.

Norrie

In reply to Armchair:

The question is, would you buy a composite pick, and then trust your life to a bit of glue?

Would the general climbing public?

having spent hundreds of thousands designing and testing the component, would they be able to make any money from it?

Steel is tried and tested, and until it becomes a pain in the arse, then it's likely to continue being used in such a fashion.

There's probably a nice set of diminishing returns for every exotic material other than steel.

In reply to Al Urker:

Just a note to thank you all for a vastly entertaining read. I shamelessly culled the highlights of this thread and posted them over in rec.bicycles.tech, where there's some debate over anodizing wheel rims that led to wondering about whether case-hardening is analogous to anodizing and might lead to fracturing.

You all sound amazingly like the bicycle crowd, right down to off-topic digressions (loved the Titanic), the name calling, and the variety of expertise being applied off-hand to odd topics.

I plan to browse some of your other threads, since this was entertaining, but I'm afraid that this is really not the place for someone with a bad fear of heights. Besides, I'm in Colorado.

Thanks,

Carl Fogel

In reply to carl fogel:

Doesn't matter if you are from Colorado although a dislike of height might be a bit of a disadvantage. Must take a look at that site, I find it mildly hilarious that anyone could think that the growth of a natural surface oxide layer on aluminium could be in anyway likened to case hardening steel.

In reply to Horse:

Dear Horse,

I fear that I started the hilarity. I blame my lack of education and fascination with bizarre analogies.

Far better informed posters are arguing now in public and private about whether anodized rims are the fracture-prone punishment for those who ignore the laws of God and man, or an unjustly maligned improvement that works just fine and inhibits corrosion.

Mechanical engineers and materials experts are reduced to calling each other names and explaining that the hard surface layer is like a scab on a knee, d'you see, and the painful cracking of the scab is just like the pain that the un-anodized sub-layer of the rim feels as cracks propagate.

Your lot seems to include more posters with a fair notion of metallurgy and a lively sense of curiosity. Ours, I regret to say, tends toward only the briefest oracular pronouncements before they start putting the boot in. (Yes, that's what my Anglo-American dictionary phrase-book says is the correct usage if I want to fit in.)

Of course, since you're all carrying ice-axes, a more polite and reasonable atmosphere is probably necessary to prevent Trotsky-style outbreaks.

Carl Fogel

In reply to carl fogel:

I can assure that forums that don't involve ice axes are far less polite!!!!

I did look for the thread over there but couldn't find it, mind you from what you say above I still think they are talking crap.

In reply to carl fogel: type-3 anodising (goldish colour) unfortunately does reduce the fracture toughness of the part, by 1/2. Not sure about the 1st and 2nd types but they're not as bad.
See ya..
Dave

In reply to Dave Noake:

Interesting, is that due to crack initiation in the anodised layer that propagates into the substrate of due to the process actually reducing the toughness of substrate?

In reply to Horse:

Dear Horse,

Here's the scene of the crime:

http://groups.google.com/groups?selm=8bbde8fc.0402201019.664b2582%40posting...

The thread rejoices in the name of "mavic rims suck?"

One group takes the affirmative and declares that rims never cracked before the evil forces of marketing unleashed anodizing upon an innocent world.

The other pack bays that un-anodized rims failed far more often than admitted because of corrosion-bred problems that only cretins would deny--there are some truly ugly pictures of bicycle rims that appear to be suffering from tertiary syphilis.

Mischief-makers like me raise ignorant red herrings about whether learned analogies about knee-scabs and anodizing hold true for case-hardening as well. (Opinion is divided.)

Blustering and ignoring obvious questions are favored tactics. My impression is that anodizing probably makes rims more prone to cracking under the tremendous tension, but that simultaneous bad re-designs for lightness are just as much at fault. (One plaintive voice keeps pointing out that only anodized rims are condemned, not the numerous other parts like seat posts, handlebar stems and front forks, but then nothing else suffers the extraordinary loads placed on pre-tensioned bicycle wheels.)

The thread is up to 269 posts, usually an indication that we're all frothing pointlessly. The easiest way to find things in rec.bicycles.tech may be through google groups, a news server that updates slowly, but which allows searching the archives back to the crack of doom:

http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&group=rec.bi...

Off now to see what waters I can muddy.

Carl Fogel

In reply to Horse:

yep pretty much - that's why 2024 is better than 7075, as 2024 has twice the fracture toughness but not as much ultimate strength as 7075. 7050 is the daddy with the best of both materials.

Dave