SCC, 316ss, and what's going on in Taiwan


Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Nate Ball wrote:

Defect or poor quality or any other weakening aside, the failure point does appear to indicate SCC, does it not? Internal stress, even in a cast material, will create a focal point that will lead to cracking and eventually a brittle failure.

As the poster above points out it is virtually impossible to say what kind of corrosion has occured by visual examination (despite John Byrnes ludicrous claims to the opposite). That it has corroded is obvious but whether it´s SCC is unknown. Crevice corrosion is the more common form from where the shackle was resting on the bolt/chain/whatever but guessing is pointless.

Nate Ball · · Portland, OR · Joined Aug 2010 · Points: 8,340

Look Jim, you make great stainless steel hardware and I'll happily vouch for them in an environment that isn't subject to SCC. I've even put some of your bolts into a crag very close to the ocean, where there have been no signs of pit/crevice corrosion in stainless steel for 20 years. Both John's bias and your own aren't particularly helpful. I don't think it's ludicrous to draw conclusions based on physical observation alone. After all, I observed dozens of cases of SCC failures and all of those samples that were tested turned out to be caused by SCC. Anecdotal perhaps, but you can see how one might start drawing premature conclusions when a.) any test results take forever, b.) you've seen the same damn thing a hundred times, and c.) you're in an environment where this phenomenon is known to occur.

So, if you suspect crevice corrosion, can you explain how this is different - insofar as it can be remedied by what's available - from SCC? My suspicion is we come right back to the "HCR or titanium" conclusion.

20 kN · · Hawaii · Joined Feb 2009 · Points: 1,348

We did not have the shackle tested. However, visually it looks identical to other items which were confirmed SCC. In any case, does it matter? If a bolt fails and your partner decks and breaks both legs, are you going to be arguing with the bros in the ER waiting room as to whether it was SCC or crevice corrosion? It doesent matter in the slightest. What matters is austenitic stainless steel can fail from multiple forms of marine corrosion including but not limited to SCC, pitting and crevice corrosion, and titanium will not fail from any of those. That's the only message that matters.



Jim Titt · · Germany · Joined Nov 2009 · Points: 490

True enough, what kind of corrosion is fairly irrelevant if the object has failed but many types can be avoided by design, different manufacturing methods and choosing different materials. Writing off ALL 304/316 bolts worldwide because someone THINKS a bolt made of an unknown material failed from SCC isn´t particularly helpful to anybody and the wilder the claims the less validity they have when normal climbers can see for themselves what gives adequate service and what doesn´t.

Nate Ball · · Portland, OR · Joined Aug 2010 · Points: 8,340

Nobody is writing off all 304/316 bolts. I would still use 304ss in a dry environment if the price difference with 316ss weren't so similar anyway. Again, your bolts have been used by people in this discussion to bolt routes near the sea that had no history of SCC. Normal climbers CANNOT see for themselves unless they are actually on the wall, removing the bolts, and know what they're looking at. The evidence is mounting that 316ss has failed already and that samples are fewer because the majority of older bolts are 304ss. It seems safe to deduce that neither of these are ideal materials. Just so we're clear, I know some people who want to believe that it is a justifiable decision to leave 316ss bolts in the wall until they fail from use, so let us be perfectly clear: do you think 316ss is a justifiable material to use at a seaside crag? Your statement "what kind of corrosion is fairly irrelevant" seems to indicate otherwise, but I'm unsure what "different manufacturing methods" you could use to make a 316ss bolt impervious to pitting/crevice corrosion in this environment.



Apparently the hanger for the Petzl Longlife has always been 316ss? Any tests that confirm this?

Jim Titt · · Germany · Joined Nov 2009 · Points: 490

Depends on what you mean by the seaside, or more exactly where. In Thailand it´s clearly not the best idea, in huge areas of the world 316 (and 304) works just fine.

Bolt-ins work less well as there are stress concentrations and areas where water can become trapped and stagnant, welded products are always more suspect, products where the bend radii are too tight are suspect, products which have not been properly cleaned and passivated are suspect, bolts which don´t get regularly washed by rain or sea water are more suspect and so on. Petzl Longlife´s were no longer certified in 1996 and were a dubious  product even then, it´s better to remove them anyway whether they are corroding or not.

Regrettably no material is "ideal" including titanium, it´s certainly better for corrosion resistance but it´s weakness, lack of wear resistance, expense of welding and the lack of commercially available compatible accesories plus the price and availability of quality raw stock make it less than ideal.

20 kN · · Hawaii · Joined Feb 2009 · Points: 1,348
Nate Ball wrote:



Apparently the hanger for the Petzl Longlife has always been 316ss? Any tests that confirm this?

The Petzl Longlife bolt as a whole is 316, not just the hanger. However, Petzl also makes their hangers in 316 as they have been for some time. There were was a time where the hangers were made from 304, but Petzl switched to 316 a very long time ago. Petzl could give you an exact date. If your oldest 316 bolts are 12 years old, then those Petzl hangers are 316 as Petzl made the switch before that.

Nate Ball · · Portland, OR · Joined Aug 2010 · Points: 8,340

Wow Jim. You're making a lot of claims here. I want to make sure we take them all down for posterity. We'll just assume your bottom line isn't effecting your responses. Just so we're clear...

Which seasides, anywhere in the world, does it "work" to use 304/316ss?

How would you make that distinction in such a way to justify the use of an SCC-prone material?

To specify my previous question: do you think 316ss is a justifiable material to use at Long Dong, given the history of failure?

What made the Longlife dubious?

My understanding is Longlifes were only ideal for hard rock, which LD is. Our Longlife failures were always in the hanger, as shown in the pics. They were all installed in the mid-90's, so were close to 20 years old when they failed. Also shown are the failures of many other types of bolts with differing manufacturing predispositions. Clearly the SCC at LD is quite accelerated to have caused this many failures of this many bolt types. Please take this into consideration before making what amount to recommendations to use stainless steel at a seaside crag.

Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Nate Ball wrote:

Wow Jim. You're making a lot of claims here. I want to make sure we take them all down for posterity. We'll just assume your bottom line isn't effecting your responses. Just so we're clear...

Which seasides, anywhere in the world, does it "work" to use 304/316ss?

How would you make that distinction in such a way to justify the use of an SCC-prone material?

To specify my previous question: do you think 316ss is a justifiable material to use at Long Dong, given the history of failure?

What made the Longlife dubious?

My understanding is Longlifes were only ideal for hard rock, which LD is. Our Longlife failures were always in the hanger, as shown in the pics. They were all installed in the mid-90's, so were close to 20 years old when they failed. Also shown are the failures of many other types of bolts with differing manufacturing predispositions. Clearly the SCC at LD is quite accelerated to have caused this many failures of this many bolt types. Please take this into consideration before making what amount to recommendations to use stainless steel at a seaside crag.

My "bottom line" is irrelevant, it would be better for me if the market changed to higher specified bolts such as 2205 or titanium as the profit margin would probably be higher as the market for normal stainless steel products is extremely competitive. The material used is the same to me, it´s just a bit of metal which I work. 

There are many hundreds of thousands of bolts in Europe in coastal locations giving good service and they are not titanium. Defining what is a "seaside" or "coastal" area is a matter of debate and varies depending on who you talk to. Defining what is an acceptable failure rate is also a complex subject.

I´ve never been to Long Dong, have no idea of the past record of failure or the climate and consider the choice of material to be a matter for those with direct experience over the years, if the climbers there are experiencing satisfactory lifespans from 316 then it is up to them to decide what to do, not a couple of internet warriors living thousands of miles away. As Francis Haden has pointed out they have good results with 316 in Hong Kong at most cliffs and are basing their rebolting on their own experience, not abitrarily imposed rules.

The LongLife anchor failed to meet the embedment depth criteria for EN959. As you say, they were acceptable in hard rock but often were installed in less suitable areas as and often in less than ideal holes, any LongLife where the pin is driven completely in is immediately suspect for obvious reasons. The design itself has areas which after installation are likely to promote corrosion and similar to bolt-ins should be used with caution where accelerated corrosion could be an issue.

 

Nate Ball · · Portland, OR · Joined Aug 2010 · Points: 8,340

Right, Jim... you're missing the point, and I feel like you're obfuscating for some other reason than just belligerence. I won't argue that inland crags - not crags right on the ocean like Tonsai and Long Dong - will have much lower likelihood of SCC and that 316ss is a fine choice for "satisfactory lifespans" in such environments. I've installed many of your bolts in those types of crags. But when we talk about a "satisfactory lifespan" in Tonsai, we aren't talking about using 316ss. Nor in Hong Kong, Hawaii, Cayman Brac, etc.

This thread was begun for the purpose of discussing the specific predicament at Long Dong. It is a seaside crag by everyone's definition. The failure history has been plainly laid out for you in detail here and in other threads. It is a warm, moist environment as you might expect from being in tropical SE Asia. When you talk about "direct experience" and "internet warrior" you're referring to the same person: me. I've done a lot of work to make the case that titanium is the solution at LD going forward, which seems to have been a success. Francis, Martin, Alan, John, and many others have been incredibly helpful in teaching me about the intricacies of this phenomenon, and I'm pretty sure we're all on the same page not because of a desire to sell more titanium, but because it's the logical solution.

Nobody is talking about "arbitrarily imposed rules". The UIAA standards would only ever be guidelines anyway. They also wouldn't be arbitrary because they are based on meticulous consideration of a complex issue.

What we ARE talking about is whether or not there is any evidence to conclude that 316ss won't fail in the near future at Long Dong. If, according to Sayar, we've already had 316ss failure in the form of the 20-year-old LongLife's (all of the failures were in the hanger, completely unrelated to any of the "dubious" aspects you referred to), then it's only a matter of time until the locally-made, uncertified, welded 316ss bolts start to fail too. There are 900+ titanium bolts ready to be used specifically for the purpose of replacing these. I wish you would commit to a clear answer, but you're right, SCC is very complicated and it's tough to make big decisions when it isn't your crag, your money, your own life on the line when you're lowering from those bolts.

However, I do hope you realize that by making this painfully obvious conclusion so much more complicated that you are definitely not helping matters for those who are trying to get real work done.

Jim Titt · · Germany · Joined Nov 2009 · Points: 490

The underlying plan behind the UIAA proposals WAS to get these forced through as mandatory for European manufacturers by changing EN959, this plan however is dead in the water due to their inability to put forward a clear and coherent argument or even a workable set of standards. There are other matters which they would also like to change which would have widespread consequences to the supply of bolts (read "cost lots more") but these also are off the table until the next review which takes place in 2027. They are now involved in lower-offs which will occupy them for the next decade anyway and end up unresolved.

I can´t give a recommendation since as I said I have no idea what is happening, what will happen in the future and what failure risk the local climbers think is acceptable. It is impossible for me to say "that bolt will fail in X years" and equally impossible for me to say "spend the next year jumaring up that cliff changing the bolts". If the local climbers feel the standard of the installed bolts is acceptable it is purely their matter, that you disagree is clear but that is a problem you and they will have to resolve and nothing we say or do will change that. They are the ones that have to do the work, not me and so my opinion is worthless.

Nate Ball · · Portland, OR · Joined Aug 2010 · Points: 8,340

If your opinion is worthless, why are you still commenting?

Of course it isn't, nor is that of the UIAA or anyone else who actually consider this discussion important, even if we can't agree on even the most basic principles. I personally find it stunning that just because you aren't in Taiwan that you can't make logical deductions; because you can't put a given bolt's lifespan into exact number of years that you can't make recommendations for a material that will certainly last orders of magnitude longer.

There ARE people doing the work, and at least part of the point of this thread is to give a logical foundation for why this is the far more practical solution than what the "official" team is doing. Unfortunately your responses have only justified their lack of commitment to any coherent plan, for which the consequences boil down to less work and more danger. How much danger? Only time will tell.

Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Nate Ball wrote:

If your opinion is worthless, why are you still commenting?

Of course it isn't, nor is that of the UIAA or anyone else who actually consider this discussion important, even if we can't agree on even the most basic principles. I personally find it stunning that just because you aren't in Taiwan that you can't make logical deductions; because you can't put a given bolt's lifespan into exact number of years that you can't make recommendations for a material that will certainly last orders of magnitude longer.

There ARE people doing the work, and at least part of the point of this thread is to give a logical foundation for why this is the far more practical solution than what the "official" team is doing. Unfortunately your responses have only justified their lack of commitment to any coherent plan, for which the consequences boil down to less work and more danger. How much danger? Only time will tell.

My opinion is worthless in the context of either telling you that all the bolts are perfect and you are wrong OR telling the Taiwanese that they are all going to die and they must change all the bolts immediately. Offering either of these opinions will not change the thinking of the two sides not will it achieve anything. 

Commenting is what forums are for.

Nate Ball · · Portland, OR · Joined Aug 2010 · Points: 8,340

Nobody is saying anyone is going to die immediately. You are constantly exaggerating and it's just distracting from the main point. Let me remind you that there was an incident at Long Dong in which both anchor bolts failed simultaneously. And the climber miraculously survived with not but a bruised ass. Sure, freak accident... it would be tragic if that happened again.

Nobody is asking for a completely one-sided opinion. Are a majority of stainless steel bolts going to fail from SCC in the next 1-30 years? Almost certainly. Is there any way to determine which ones and when? No. So how do we address the general problem? Rebolt with a non-susceptible material (guess what, it's already ready to be installed). What do we risk by not doing so? Other people's safety.

I mean, yeah, that is an easy pinata to beat up on, but when you're the one making the decisions but not actually depending on those bolts, you have a different perspective.

By the way, commenting isn't adding points anymore.

Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Nate Ball wrote:

Nobody is saying anyone is going to die immediately. 

Including myself  

The easiest way for climbers to safeguard themselves against failure of suspect bolts is to test them, the recommended test by the DAV (put a karabiner crossways in the eye and twist it with one hand) is, depending on the karabiner size and ones strength, an indication that the bolt (and resin bond) will hold around 8kN which is adequate for most purposes. This test is derived from sampling a large number of poorly designed/made bolts and subsequenty pull testing them.

I´ve investigated further on other bolts and twisting a normal climber (me) can impose a little over 20Nm (15ft.lbs) on the bolt, by progressively reducing the thickness of the shaft one discovers this equates to a bolt strength of ca 10kN so their rule is accurate enough.

Nate Ball · · Portland, OR · Joined Aug 2010 · Points: 8,340
all the bolts are perfect and you are wrong OR Taiwanese are all going to die and they must change all the bolts immediately.

Hyperbole much? For the sake of informed discussion, let's avoid this kind of wildly inaccurate and misleading rhetoric, mkay? There is clearly a middle ground, and that doesn't include the continued use of 316ss for rebolting, even if it doesn't mean immediately replacing all 316ss bolts regardless of age or micro-environment.

Can you please link to this DAV test you're talking about? And would it be accurate in determining the presence of advanced SCC?

Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Nate Ball wrote:



Can you please link to this DAV test you're talking about? And would it be accurate in determining the presence of advanced SCC?

No idea where the DAV put it all, I was involved in some of the testing (I built the tester) and the recommendation came out ten or more years ago. It´s somewhere in the Panorama archives regarding Sigi bolts. Here´s the version from the guidelines on bolting from the Austrians:-

Hierzu verkantet man
einen Karabiner im Haken (kleine Hebelwirkung) und versucht
diesen per Hand zu drehen. Lässt sich der Haken so
lösen, ist die Festigkeit nicht ausreichend. Kann der Haken
so nicht gelöst werden, ist die Festigkeit ausreichend. Ein
Verbundmörtel härtet entweder aus oder nicht. Mittelfest
gibt es also nicht.

The German testing covered both poor bonding as the bolts in question had very little engagement in the resin and also the mechanical strength of the bolts themselves as a large number were welded using the incorrect grade of stainless, the end result was if they withstood the karabiner test they could be considered to hold ca 8kN which is why this test was developed. I´ve subsequently tested only for material failure and get results which show good correlation (I can break a 10kN bolt but that might be due to using a larger karabiner or because I´m a big guy that bends metal for a living). 

The bolt doesn´t know why it´s weakened, whether it´s SCC, crevice corrosion or because I put a grinding disc halfway through, it´s just a function of how much metal is left holding it together. A piece of 6mm stainless will hold about 22kN, cut it halfway through and I can just twist it off with a large karabiner and so on, it´s easy enough to test yourself.

I use torque testing to test my  bolts in production which is why I´m familiar with the idea, when I twist the bolts up I can continue until they shear off and read the load on the machine at the same time. Rather than pull testing It´s much quicker to just overtwist and see what they withstand before failure.

Nate Ball · · Portland, OR · Joined Aug 2010 · Points: 8,340

So you would definitely test to failure? Or if bolts withstand twisting by hand with a carabiner then it's okay?

One problem I see with this method, which is the same for any method, is that it doesn't detect whether or not a bolt currently has SCC, and thus when it will fail. It only tells you that the bolt you are likely clipped into will fail. Good luck doing this with your rappel anchors.

Jim Titt · · Germany · Joined Nov 2009 · Points: 490
Nate Ball wrote:

So you would definitely test to failure? Or if bolts withstand twisting by hand with a carabiner then it's okay?

One problem I see with this method, which is the same for any method, is that it doesn't detect whether or not a bolt currently has SCC, and thus when it will fail. It only tells you that the bolt you are likely clipped into will fail. Good luck doing this with your rappel anchors.

I test to failure in production to ensure the material is up to spec as part of my QC system. 

The twist test with a karabiner is a reasonably accurate test to indicate a bolt is adequately glued into place and that corrosion hasn´t weakened it to the point it would not hold a fall.

The last bit seems a bit confused! It doesn´t tell you the bolt is likely to fail, the exact opposite if it survives the test.

Nate Ball · · Portland, OR · Joined Aug 2010 · Points: 8,340

My point is just that this test only determines if the bolt is safe NOW. If it doesn't break, great, if it does, well... just hope it doesn't happen to BOTH anchor bolts. Also, I'm not sure how you would be doing this unless you are on rappel or TR. In which case you will have already led the route, clipping the bolts, and trusting them as you go.

Regardless, it seems we've already arrived at the conclusion that there is no testing protocol to determine the life expectancy of stainless steel bolts in an environment with SCC. A pull-tester could determine at what force the failure occurs, but in the end all you're doing is collecting data points on how many bolts and what types are failing where. How many failures are acceptable until a given material/model is replaced?

In the case of LD, we have failures of 316ss nail-drive bolts (Petzl LongLife) and 304ss cold-bent (AustriAlpin, Ferno), welded (Fixe), and hot forged (Petzl Collinox) glue-in bolts. All of these failures occurred in less than 20 years, usually closer to the 8-15 year range. These have all been deemed unsafe and are on their way to being completely removed and replaced.

There are only two bolt types without precedent for failure, and those are welded 316ss glue-ins - both Fixe and a Taiwan-made copy. The majority are in the 10-12 year range. This is what we are discussing... are these bolts an imminent risk for failure from SCC? How can we make a determination either way? If we can't possibly know, then what is the prudent course of action?

Here are some pics of the TW-made 316ss bolts pre-installation:

Guideline #1: Don't be a jerk.

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