# Corrosion testing Damasko's steel



## Will_f

FINAL UPDATE 9-20-15: Well, the verdict is in: Damasko steel, while being much harder than 316L Stainless, is not as corrosion resistant. Go to the end for details.

Will

UPDATE (For those that don't want to read all the posts): after a little less than a week there is superficial putting on the 316L stainless steel links. There's possibly pitting on the Damasko links, but I can't really tell with the blasted surface. One of the screws on the Damasko bracelet appears to have a defect causing it to corrode quite significantly compared to the 316L & Damasko steel. I don't know what the screw is made of, but I suspect stress crack corrosion from when the screw was made.

So, lately there's been a bit of contoversy about what steel Damasko uses in their watches. Some folks think it's not as good as 316, some folks think it may be 440C (A decent, but not particularly corrosion resistant martensitic stainless) and some think it's Cronodur 30 (based on an interview with Damasko).

Being the kind of guy that I am I debated sending off a sample to a lab and having them test it, but then I came up with a better idea: Do corrosion test! The test is a little jury rigged (I used what was lying around the house) but I think it will work.

Test method: 
I have 3 metal samples: (1) a marine bronze watch buckle from my bronze Makara. (2) 316L SS links from a Momentum dive watch. (3) A link from my Damasko bracelet.

The metal samples are immersed in an aeriated saturated solution of hydroponics fertilizer (mostly nitrogen salts with phosphorous and potassium salts as well) buffered to pH 4. The TDS is around 8000 ppm. I used fertilizer because it's about the most corrosive salt solution I could find in the house and bonus, it is mildly acidic. The aeration is accomplished with two aquarium bubblers to make sure there is plenty of O2 available for oxidation.

I'll take pictures every couple of days or so until a clear winner is identified.

Macro Photos will come later (my photo editing computer crashed and I'm restoring it as I type). However, here's a pic of the test setup. You can see the excess fertilizer sitting in the bottom of the tub.


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## dimman

I'm not much of a chemist, but PREN numbers are based on chloride pitting which has to do with 'normal' salt water. My simple understanding is that electrolysis transforms the salt water and steel into ferric chloride on the surface which is an etchant that attacks stainless steel creating microscopic craters.

Don't know anything about fertilizer, but I would think just plain salt water (marine amounts) is sufficient given the typical operation environments. 

Thanks for sacrificing your links in the pursuit of knowledge. Though it would be a whole lot simpler if Damasko just said '440C' or '1.4108' or 'Coridur 30' right on their website. They put a lot of technical metallurgical stuff on it, yet still avoid naming the actual alloy used. Annoying.

Interesting side note about Coridur and PREN. Coridur seems to rely on Nitrogen for both hardness and corrosion resistance. Nitrogen has a major effect on PREN, and doing the calculations on Coridur's composition the allowed range of 0.3%-0.%5 Nitrogen creates a huge possible swing in potential corrosion resistance (Nitrogen is weighted 16 times).


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## Will_f

Dimman said:


> I'm not much of a chemist, but PREN numbers are based on chloride pitting which has to do with 'normal' salt water. My simple understanding is that electrolysis transforms the salt water and steel into ferric chloride on the surface which is an etchant that attacks stainless steel creating microscopic craters.
> 
> Don't know anything about fertilizer, but I would think just plain salt water (marine amounts) is sufficient given the typical operation environments.
> ).


Didn't have enough salt sitting around the house to use it up without antagonizing the boss, but I'll dump a bunch in after I go to the store. Salt and fertilizer can't hurt and anything which speeds the process is good IMHO.

Anyway, it looks like my desk-top is going to be out of commission for at least a day or two so here's some pics of the samples before they went in:

Marine bronze buckle








316L bracelet links:








Damasko link


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## whoa

Holy... Well that's cool! I actually thought they used their own metal? Or mix or what you call it? Pretty sure i read that on a watch review site or something. Am I misunderstanding something, or do people think it's not true?  English is not my main language and this is very technical, so might have missed some things :-D 

But very cool project :-D 

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## Avo

Just what exactly are we supposed to learn from this test?


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## Will_f

Avo said:


> Just what exactly are we supposed to learn from this test?


The test is Damasko steel more corrosion resistant than 316L. I thought that part was kind of obvious. I put the Bronze in because it will probably be the most interesting to watch.

Anyway,
Salt added.


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## dimman

Will_f said:


> The test is Damasko steel more corrosion resistant than 316L. I thought that part was kind of obvious. I put the Bronze in because it will probably be the most interesting to watch.
> 
> Anyway,
> Salt added.
> 
> View attachment 5173714


Here are some PREN ranges (based on alloy % tolerances of the steels) for some of the materials we are talking about:

440C: min 16, max 20.48
316L (1.4404): min 23.1, max 28.5
Cronidur 30: min 21.6, max 27.63
316L (1.4435): min 25.25, max 30.66 *

And the king 904L: min 32.2, max 39.9

* This 316L is the Staybrite version used by high-end Swiss case-makers.

I know some Momentum watches are made by Full Swing and likely use the base 316L.

Interested to see what the results of this will be. But from looking at the numbers even if Damasko uses Cronidur I don't care for the low range of the PREN, which could indicate why occasional rust problems pop up. If I get a DA46, I will opt for the Damest coating rather than the bare metal.


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## Will_f

I'm going to to take the PREN numbers with a grain of salt (pun intended). I'm much more interested in seeing what actually corrodes. I did find a Cronodur spec sheet listing a PREN of 30, but as its a theoretical calculation and not a test, it may not be the best measure.

Link to Cronidur spec:

http://www.energietechnik-essen.de/...dukte/dateien/Data-sheet_Cronidur-UK-2012.PDF


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## dimman

Will_f said:


> I'm going to to take the PREN numbers with a grain of salt (pun intended). I'm much more interested in seeing what actually corrodes. I did find a Cronodur spec sheet listing a PREN of 30, but as its a theoretical calculation and not a test, it may not be the best measure.
> 
> Link to Cronidur spec:
> 
> http://www.energietechnik-essen.de/...dukte/dateien/Data-sheet_Cronidur-UK-2012.PDF


That's an optimistic bar graph. If you use the Chrome, Molybdenum and Nitrogen content range you end up with the above figures.

PREN is a well established engineering parameter for specifying materials in marine/chloride environments.

Edit:

Those corrosion figures in the marketing brochure don't add up. Their PRE must be different than PREN.

The comparison alloys 1.4125 (440C) and 1.4112 should have figures of 16-20.48 and 19.997-23.29 respectively. So there obviously some inflationary influence in the marketing brochure's corrosion calculations.


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## Will_f

Dimman said:


> That's an optimistic bar graph. If you use the Chrome, Molybdenum and Nitrogen content range you end up with the above figures.
> 
> PREN is a well established engineering parameter for specifying materials in marine/chloride environments.


Sure, but it seems likely you can have two materials with the same PREN and different performance in salt water. I would not be surprised if heat treatment, surface treatment, etc all play a role.


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## dimman

Will_f said:


> Sure, but it seems likely you can have two materials with the same PREN and different performance in salt water. I would not be surprised if heat treatment, surface treatment, etc all play a role.


Heat treatment, surface, etc... play a role in corrosion, yes. But the PREN is based on the underlying alloy. Conditions/treatments have an effect, but if they are equivalent the higher PREN material will be more resistant. Science is serious business. If someone wants to hype their material as superior and uses a 'test' of say an unwelded and passivated (theirs) vs welded and sanded (brand X) part to 'prove' that the base material is better, no one will take the results seriously.


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## rationaltime

Will_f said:


> Didn't have enough salt sitting around the house to use it up without antagonizing the boss, but I'll dump a bunch in after I go to the store. Salt and fertilizer can't hurt and anything which speeds the process is good IMHO.


I like to see we have experimentalists among the members.
It is too bad there is no good place in Anchorage to find sea water.

Thanks,
rationaltime


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## Will_f

rationaltime said:


> I like to see we have experimentalists among the members.
> It is too bad there is no good place in Anchorage to find sea water.
> 
> Thanks,
> rationaltime


You do have a sense of humor Rationaltime. Did you spend some time in Anchorage?


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## Will_f

Dimman said:


> Heat treatment, surface, etc... play a role in corrosion, yes. But the PREN is based on the underlying alloy. Conditions/treatments have an effect, but if they are equivalent the higher PREN material will be more resistant. Science is serious business. If someone wants to hype their material as superior and uses a 'test' of say an unwelded and passivated (theirs) vs welded and sanded (brand X) part to 'prove' that the base material is better, no one will take the results seriously.


Why don't we just wait and see what the results show? At the moment we're just speculating.


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## Will_f

Found an interesting test of Cronidur 30 in salt spray:

https://www.google.com/url?sa=t&sou...r8lP8eNfdh8CGj46A&sig2=ZjADFc8RpX4xm9KUFJVBKQ

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## Avo

Will_f said:


> The test is Damasko steel more corrosion resistant than 316L. I thought that part was kind of obvious. I put the Bronze in because it will probably be the most interesting to watch.


Um, OK, but why is resistance to this particular mix of chemicals especially interesting or important?

I'm quite interested in knowing how corrosion-resistant Damasko steel is to conditions that might reasonably be encountered in actual wear, such as exposure to ocean water followed by air drying, or prolonged exposure to high-humidity climates. Will your results be relevant to these questions?


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## Will_f

Avo said:


> Um, OK, but why is resistance to this particular mix of chemicals especially interesting or important?
> 
> I'm quite interested in knowing how corrosion-resistant Damasko steel is to conditions that might reasonably be encountered in actual wear, such as exposure to ocean water followed by air drying, or prolonged exposure to high-humidity climates. Will your results be relevant to these questions?


Dimman probably knows better than me but here's my understanding: Stainless steel is fairly corrosion resistant because it has a surface layer of oxidation which prevents further corrosion from occurring. While that layer of oxidation doesn't protect the steel against everything, it does protect against a lot. However, strong acids and Chlorides can and do attack stainless. Since sweat and seawater contain chlorides and are a little acidic, that is typically what causes pitting (leading to loss of water resistance) on stainless steel watches. 316L is pretty resistant to chlorides, but 440C is not. Cronidur (which is what Damasko apparently uses) is definitely more corrosion resistant than 440C, and similar to 316L if you go by PRE number. With any luck, we should be able to see how the Damasko links fare in comparison with a 316L bracelet and a piece of marine grade bronze. If it's comparable to 316L then that's excellent for a nickel free hardened steel and should last for many decades. If it performs better than 316L then even better. By the way, the Bronze is holding up very nicely. It's sensitive to a lot of things, but seems pretty tolerant (so far) to salty water.


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## Okapi001

Avo said:


> Um, OK, but why is resistance to this particular mix of chemicals especially interesting or important?
> 
> I'm quite interested in knowing how corrosion-resistant Damasko steel is to conditions that might reasonably be encountered in actual wear, such as exposure to ocean water followed by air drying, or prolonged exposure to high-humidity climates. Will your results be relevant to these questions?


Yes, his results will show in one week if special steel is any better than ordinary, and what can happen to a watch in several years of actual wear.


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## Dragonutity

Remind me of Chem class


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## blowfish89

You have the right combination of geekiness and coolness we all aspire to, Will. b-)

Look forward to the results. Will read the full post when more pics are added, but I understand what its about.


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## Jax

I'm very interested in the results of this test. 


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## gringosteve

I would expect dots of rust only which will remove easily with metal polish


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## Rarirurero

Having seen 2 owners of Damasko watches here from the same country as I am complaining about rust and corrosion on their pieces has me a bit worried as well. The high humidity here might play a part, I'll monitor my DA47 through daily usage and report of any rust or corrosion.


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## faiz

Thanks for sacrificing your links!


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## Will_f

Found a NASA report on testing of Cronidur 30 against some other high performance metals:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20150006942.pdf

It suggests we may be waiting a while to see any changes. They tested it for 359 days in salt spray and it looks pretty much fine. In the interest of speed, I am planning on spiking the salt bath with bleach to speed up the process.

Will


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## MrDagon007

Well you will not have a real life study if you add bleach unless that is your habitat.
I have a Böker pocket knife with a Cronidur blade, very stainless indeed and harder than 316L (but not as hard as some premium knife steels which would probably be too corrosion susceptible for a watch case). Though I expected it to be a rather expensive steel for watch cases.
Btw I do understand that mr Damasko doesn t publish his exact steel. Let the competition find out good steels on their own.


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## acr4

Will_f said:


> In the interest of speed, I am planning on spiking the salt bath with bleach to speed up the process.


Be careful. If you already have an acidic solution (pH<7) and you plan on adding bleach (chlorine bleach I presume?) with a pH of 11-13, then dangerous quantities of chlorine gas may be liberated. I think you're much safer starting over with fresh salt water.

A safer option might be to create a super-saturated saline solution - bring a pot of water to a boil with a large amount of salt (stainless steel pot only - no aluminum or you'll cause pitting in that too!). Once dissolved, let cool until safe to handle, then add the links.

Chemistry is fun, but remember kids, adult supervision required. It's still very easy to burn/poison oneself with common household chemicals.


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## Will_f

acr4 said:


> Be careful. If you already have an acidic solution (pH<7) and you plan on adding bleach (chlorine bleach I presume?) with a pH of 11-13, then dangerous quantities of chlorine gas may be liberated. I think you're much safer starting over with fresh salt water.
> 
> A safer option might be to create a super-saturated saline solution - bring a pot of water to a boil with a large amount of salt (stainless steel pot only - no aluminum or you'll cause pitting in that too!). Once dissolved, let cool until safe to handle, then add the links.
> 
> Chemistry is fun, but remember kids, adult supervision required. It's still very easy to burn/poison oneself with common household chemicals.


Don't worry, I work for an organization that designs, builds, and operates water treatment plants. Experience with chlorine I have so I neutralized the pH first. That said, the house still smells like a swimming pool.


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## Will_f

MrDagon007 said:


> Well you will not have a real life study if you add bleach unless that is your habitat.
> I have a Böker pocket knife with a Cronidur blade, very stainless indeed and harder than 316L (but not as hard as some premium knife steels which would probably be too corrosion susceptible for a watch case). Though I expected it to be a rather expensive steel for watch cases.
> Btw I do understand that mr Damasko doesn t publish his exact steel. Let the competition find out good steels on their own.


Everything I've read says that unless I raise the temperature substantially, I'm going to be waiting a very long time before I see much difference between 316L and Cronidur 30. Raising the temperature is problematic, so...

The literature on Both metals show they're both going to hold up for a long time in room temperature salt water, so I have to up the challenge. The mechanism for corrosion involves Cl- ions. Bleach will magnify the corrosivity without changing the basic mechanism for corrosion. I've realized this isn't really about how well Damasko steel is likely to hold up under salty conditions (Assuming it's Cronidur 30). It's about is it as good or better than 316L? For most uses, both 316L and Cronidur 30'are more than sufficiently corrosion resistant for watch cases.

Assuming the Cronidur performs similarly to 316L, it's going to be fine for anything but the most extreme conditions.


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## Will_f

Photo update: my main PC is still not running so the photos aren't the best. That said, I can't see any sign of corrosion on either of the S'S samples. The bronze sample is developing a nice patina though..























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## rationaltime

Will_f said:


> Everything I've read says that unless I raise the temperature substantially, I'm going to be waiting a very long time before I see much difference between 316L and Cronidur 30. Raising the temperature is problematic, so...
> 
> The literature on Both metals show they're both going to hold up for a long time in room temperature salt water, so I have to up the challenge. The mechanism for corrosion involves Cl- ions. Bleach will magnify the corrosivity without changing the basic mechanism for corrosion. I've realized this isn't really about how well Damasko steel is likely to hold up under salty conditions (Assuming it's Cronidur 30). It's about is it as good or better than 316L? For most uses, both 316L and Cronidur 30'are more than sufficiently corrosion resistant for watch cases.
> 
> Assuming the Cronidur performs similarly to 316L, it's going to be fine for anything but the most extreme conditions.


If you think it over you already know this. Bleach is not chloride. 
Bleach is an ion of chlorine plus oxygen which is a strong oxidizer.
That would definitely change the corrosion mechanism. As pointed
out in the safety lecture if you still have the fertilizer in the mix
some interesting reactions may occur.

Thanks,
rationaltime


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## Will_f

rationaltime said:


> If you think it over you already know this. Bleach is not chloride.
> Bleach is an ion of chlorine plus oxygen which is a strong oxidizer.
> That would definitely change the corrosion mechanism. As pointed
> out in the safety lecture if you still have the fertilizer in the mix
> some interesting reactions may occur.
> 
> Thanks,
> rationaltime


Actually, before I did it, I read up a bunch on SS corrosion. A couple articles for your consideration:

http://www.electrochemsci.org/papers/vol6/6093913.pdf

http://www.parrinst.com/wp-content/...1/07/Parr_Stainless-Steels-Corrosion-Info.pdf

Both Cl- and ClO- attack SS essentially the same way through crevice corrosion and pitting.

In any case, I'm not willing to wait the months and months it will take to rust 316L & Cronidur in room temperature salt water.


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## CitizenM

I would strongly suspect that any increase in corrosion, if such an increase exists, would be more due to the bead blasting than the alloy.


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## Will_f

CitizenM said:


> I would strongly suspect that any increase in corrosion, if such an increase exists, would be more due to the bead blasting than the alloy.


It remains to be seen whether bead blasting is better or worse than brushed. Certainly both should be worse than polished. I expect corrosion to show up first in the crevices between the links and the pins though.

There's another formula out there for comparison of different alloy pitting resistances called Measure of Alloying for Resistance to Corrosion (MARC).

316L MARC = 34
Cronidur 30 MARC = 36

These numbers are approximate given the variability in metal composition, and from what I've read both MARC and PRE are only useful to a point. It remains to be seen how 316L and Cronidur will compare since I haven't found a test in the literature that directly compares their performance.


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## CM HUNTER

Will_f said:


> It remains to be seen whether bead blasting is better or worse than brushed. Certainly both should be worse than polished. I expect corrosion to show up first in the crevices between the links and the pins though.
> 
> There's another formula out there for comparison of different alloy pitting resistances called Measure of Alloying for Resistance to Corrosion (MARC).
> 
> 316L MARC = 34
> Cronidur 30 MARC = 36
> 
> These numbers are approximate given the variability in metal composition, and from what I've read both MARC and PRE are only useful to a point. It remains to be seen how 316L and Cronidur will compare since I haven't found a test in the literature that directly compares their performance.


Kudos to you for doing this. Regardless of the posts for the best way to rust something away, corrosion is corrosion, and at least you're putting something through a thorough test. Regardless of the underlying metal, the end result that you're buying is what matters when seeing how it holds up, so the test of the Damasko link is very intriguing to me.


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## dimman

Will_f said:


> It remains to be seen whether bead blasting is better or worse than brushed. Certainly both should be worse than polished. I expect corrosion to show up first in the crevices between the links and the pins though.
> 
> There's another formula out there for comparison of different alloy pitting resistances called Measure of Alloying for Resistance to Corrosion (MARC).
> 
> 316L MARC = 34
> Cronidur 30 MARC = 36
> 
> These numbers are approximate given the variability in metal composition, and from what I've read both MARC and PRE are only useful to a point. It remains to be seen how 316L and Cronidur will compare since I haven't found a test in the literature that directly compares their performance.


PREN is specifically to do with chloride pitting and is almost universally used for specifying materials for continuous marine duty.

I don't know exactly what's in your fertilizer brew, but the nickel in 316L is a major contributor to anticorrosion performance in other mediums.

This is why a straight salt environment is more appropriate test. Most of our watches just see salt water/sweat. (Though I don't know anything about biological pH/acid...)

Edit:

After some hunting, I found the elements/formula that MARC uses and I'm puzzled. It weighs carbon very highly and penalizes nickel. Anecdotally on knife forums they seem to believe that higher carbon decreases corrosion resistance. It is also the first (only?) proposed system to make carbon beneficial. PREN is far, far more common.

I compared 904L (a proven, documented marine steel) vs 440C (which is well documented as a poor marine steel). Ended up with a range of 26.5-32.1 for 904L vs 35-43.75 for 440C. Hmm...


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## Will_f

Dimman said:


> PREN is specifically to do with chloride pitting and is almost universally used for specifying materials for continuous marine duty.
> 
> I don't know exactly what's in your fertilizer brew, but the nickel in 316L is a major contributor to anticorrosion performance in other mediums.
> 
> This is why a straight salt environment is more appropriate test. Most of our watches just see salt water/sweat. (Though I don't know anything about biological pH/acid...)


Bear with me- I'm leaning as I go.

Re MARC vs PREN: from what I've read, for low / no nickel steels, PREN does not take into account the synergistic corrosion resistance benefit between Mb and N, or the decrease in pitting resistance from Mn. It also doesn't account for the benefit of Carbon. MARC was developed to address this. Is it better? Heck if I know. That doesn't mean I shouldn't include it. See below link:

http://or.nsfc.gov.cn/bitstream/00001903-5/63710/1/1000000965312.pdf

Re straight salt water test: in hindsight, you're probably right that the fertilizer was not the right choice. Not so much because of the potential for strange chemical reactions, but because it's not likely to do anything at all. It's essentially Potassium Nitrate, Sodium nitrate, some phosphates, and a bunch of micronutrients and buffers. Halogens appear to be the weakness of stainless steel because they penetrate the passive oxidized outer layer. Next time I go to the store I'll pick up more salt.

I very much appreciate your involvement because you apparently have quite a bit of metallurgy knowledge. The only concern I have is that you seem to be looking for reasons why 316L has to be better than whatever Damasko uses. If so, I'm ok with that. Will you be ok if it turns out Damasko's steel is as good or possibly better than 316L?


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## dimman

Will_f said:


> Bear with me- I'm leaning as I go.
> 
> Re MARC vs PREN: from what I've read, for low / no nickel steels, PREN does not take into account the synergistic corrosion resistance benefit between Mb and N, or the decrease in pitting resistance from Mn. It also doesn't account for the benefit of Carbon. MARC was developed to address this. Is it better? Heck if I know. That doesn't mean I shouldn't include it. See below link:
> 
> http://or.nsfc.gov.cn/bitstream/00001903-5/63710/1/1000000965312.pdf
> 
> Re straight salt water test: in hindsight, you're probably right that the fertilizer was not the right choice. Not so much because of the potential for strange chemical reactions, but because it's not likely to do anything at all. It's essentially Potassium Nitrate, Sodium nitrate, some phosphates, and a bunch of micronutrients and buffers. Halogens appear to be the weakness of stainless steel because they penetrate the passive oxidized outer layer. Next time I go to the store I'll pick up more salt.


I'd never heard of MARC until your post. The carbon benefit doesn't seem to be supported via decades of use of stainless steels in marine use.

Anyways I've been doing a bunch more research because of this thread and it's looking to me now that Coridur is the likely suspect. The hardness and PREN ranges support it as well as the Space Shuttle's pump upgrade.

Also finding the occasional rust on Damasko's thread here, and Damasko dealing with it promptly, combined with the PREN range of Coridur, leads me to believe that maybe a batch were made with steel from the lower range of the alloy content permitted (where it's similar to upper range 440C). This would neither be a fault of the steel mill nor Damasko but a limit of the tolerances of the material.

I looked at finding a high strength austenitic stainless called Nitronic 50 for case use and compared it to 904L. Nitronic 50 is harder and much stronger than 904L with an average PREN over 32 (suitable for continuous seawater duty). However the minimum alloy content allows for it to dip into the high 20s. Rolex's use of 904L is probably because the minimum is a touch over 32. So Rolex specced a steel so that the minimum will still meet continuous marine duty. Gotta respect their engineers even if it's seriously overkill. I've since identified a superior to 904L alloy that's not a crazy super alloy but can't get it in small quantities. Nitronic 50 I can. There is also a 317LMN that offers a minimum PREN of over 32 for less money than 904L, haven't found small quantities yet.

Back to Damasko, their website seems to indicate that they are changing to a through hardening austenitic stainless steel with a supplementary surface hardening which is cool tech, and opens another metallurgical mystery...


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## Will_f

I spotted a bit of color this morning! Will take pics tonight and post. Stay tuned.


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## gringosteve

Why not throw a parsnip in as well. Sounds just as scientific


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## Nokie

This is a very informative thread. I have been reading it daily for updates. Thanks for taking the time to post this.


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## Will_f

OK, Time for another update. First, the Marine Bronze Sample. This is holding up great if you like a nice patina on your bronze watch. There's a little salt trapped in the lettering:









The Bronze tongue has a nice crack in it from when it was bent. The oxidation really makes it stand out. The stainless steel (probably 316L) springbar is holding up great.







\

Next up is are the links from my daughter's old Momentum diver. You can see some superficial pitting on the surface (all those little white dots) but other than that, no problems observed.









A closer picture:








Finally, the Damasko. Clearly observable red oxide around one of the screws. Otherwise looks flawless.









Better take a closer look. There's a problem here:














Looking even closer, while there's a fair amount of rust staining on the Damasko link, there isn't any pitting. That suggests the link isn't causing the rust.. Rust forms near the pit (or crevice) that is actually the site being attacked. time to look at the other parts for the pitting. The next couple photos do not show anything that would cause the rust seen.















There it is- on the side of the screw head. You can also see there's a fair amount of etching of the side of the screw:









Well, all the parts but that screw go back in solution tomorrow. I'll reassemble the rusty link with the pin and one of the other screws and see if it continues to fail or if it was the screw. When I get to it I'll send Damasko an email asking what material the screw is made from.

Sorry about the blurry pics. I'm pretty much operating at the limit of what I can do with my camera.

Will


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## Will_f

I decided to put the screw back in too. Might as well verify it is the screw that is failing. I screwed it onto a pin so I could find it. These things are Tiny!


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## Battou62

Very nice info. it looks like Damasko might need to look into their screws a bit.


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## dinexus

Fascinating stuff. Always love a good torture test thread. 


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## MrDagon007

Battou62 said:


> Very nice info. it looks like Damasko might need to look into their screws a bit.


Well this is an extreme test. I wear my bracelet in humid sweaty hong kong and singapore since it was released more than a year ago and no issues in that respect.


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## Will_f

MrDagon007 said:


> Well this is an extreme test. I wear my bracelet in humid sweaty hong kong and singapore since it was released more than a year ago and no issues in that respect.


Definitely a torture test. I've never seen any sign of rust on either of my damaskos despite taking them to the beach and wearing in the shower every morning.


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## Will_f

So, today was a bad day for the Bronze. Lots of copper salts:









The 316L isn't getting away without a problem either. Crevice corrosion starting around one of the link pins. My link pin puller broke so we'll have to watch this one from the outside:















The Damasko screw that was suspected last time looks fine. Pulling it out eliminated the crevice corrosion and solved the problem.














Here's the previous pic for comparison:









The Damasko looks about the same as before. There might be some pitting at the shoulder.















Previous picture for comparison again.









What do I conclude from this so far? The 316L and the Damasko steel are probably on the same order of corrosion resistance. They all go back in the tank tomorrow and we'll see what develops in a few more days.

Will


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## asrar.merchant

Love the work Will. Can't thank you enough for this education you are providing us with. 

I am sure all of us feel the same about your efforts and labour, even if it is labour of love. 


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## Bighand

Thank you for posting. Very interesting work. I have been hesitant to seriously consider "hardened" watch products after reading a few threads about the performance of Damasko and Archimede products. Now if the watch manufacturers would just have the courage to conduct a similar test and post the results. Would be telling to see how other similar metals, such as 6Steel, perform. In other words, less marketing stories and more objective (and verifiable) results from the watch manufacturers.


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## Will_f

Bighand said:


> Thank you for posting. Very interesting work. I have been hesitant to seriously consider "hardened" watch products after reading a few threads about the performance of Damasko and Archimede products. Now if the watch manufacturers would just have the courage to conduct a similar test and post the results. Would be telling to see how other similar metals, such as 6Steel, perform. In other words, less marketing stories and more objective (and verifiable) results from the watch manufacturers.


I agree. That said, I have owned a Damasko since 2011 and never seen a speck of corrosion on it. If you are happy with the performance of your 316L, you'll be happy with Damasko's hardened steel. A caviat though, I've seen a number of vintage watches from Southern Asia made from 316L that were badly pitted at the case-back seal. You couldn't see it without opening the watch because it was hidden under the case back. Here's a couple examples on a 30 y.o. Rolex. The original owner is my father in law and I can pretty much guarantee the watch never went into the ocean.:















It tells you about the only materials out there that I would not expect to ever corrode are gold, platinum, and 904L.

If you live in a high humidity hot climate and you're buying a watch and expecting it to last for generations, gold, platinum, and 904L are probably your best options.


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## dimman

Interesting how corrosion starts in roughly the same place on both. I wonder if it has to do with the pins/screws rubbing down the protective chrome oxide as they move and if the metals are slightly different alloys between the link and pin/screw increasing the electrolysis effect. 



Thanks for the link sacrifice, Will.


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## Will_f

Dimman said:


> Interesting how corrosion starts in roughly the same place on both. I wonder if it has to do with the pins/screws rubbing down the protective chrome oxide as they move and if the metals are slightly different alloys between the link and pin/screw increasing the electrolysis effect.
> 
> Thanks for the link sacrifice, Will.


Possibly. A little movement in the bath could wear the 40 angstom layer of protective oxide, and crevice corrosion takes it from there. It could also be that a defect in the metallurgy or surface provides a toehold.


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## whoa

Just a quick question, I don't know the English word for it, but couldn't the rust be "spread" from one of the metals to the others when they are in the same bath? It happens for instance in a dishwasher if you put some bad quality steel in it, and it can make ss get rust spots?

Sendt fra min HTC One S med Tapatalk


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## Will_f

whoa said:


> Just a quick question, I don't know the English word for it, but couldn't the rust be "spread" from one of the metals to the others when they are in the same bath? It happens for instance in a dishwasher if you put some bad quality steel in it, and it can make ss get rust spots?
> 
> Sendt fra min HTC One S med Tapatalk


Here's my understanding: Corrosion of stainless in salt works like a battery with the pit / crevice as the anode and the metal outside the pit like a cathode. The pit is low in oxygen so iron is pulled off by Cl- ions, leaving behind an electron which moves through the steel to the oxygen rich solution outside of the pit where oxygen, h2o, and Fe+ combine to precipitate out as Fe(OH)3 (rust). This occurs near the pit. Rust accumulates near the point of attack.


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## FFabian

Bighand said:


> I have been hesitant to seriously consider "hardened" watch products after reading a few threads about the performance of Damasko and Archimede products.


What? I'm considering a Damasko watch. Please explain.


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## WatchMann

Will_f said:


> Definitely a torture test. I've never seen any sign of rust on either of my damaskos despite taking them to the beach and wearing in the shower every morning.


 I can verify this is a rarity, over the years we have never had one come in with this.


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## Will_f

FFabian said:


> What? I'm considering a Damasko watch. Please explain.


I don't think there's any significant concern re the hardened stainless Damasko uses vs standard 316L used in most watches. The problem with stainless that can be through hardened (as opposed to surface hardened which is different) is that most are more susceptible to salt water corrosion than 316L. Damasko uses an alloy which was created to be corrosion resistant while still being very hard. As an added bonus, Damasko's alloy is also low on nickel and therefore unlikely to cause an allergic reaction.

My expectation prior to conducting this test was that Damasko's alloy would be significantly more corrosion resistant than 316L. That does not appear to be true, but at the same time it does not appear to be significantly less corrosion resistant. If you are are not having problems with your SS watch, you are very unlikely to have problems with a Damasko.


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## Jax

Is it just the screw on the Damasko that is rusting or the steel itself? It's possible that they're not using the same metal in the screws as in the link and the case, right? The screws won't scratch like the bracelet will so I'd assume that they use different steel but I could be wrong. 


Sent from my iPhone using Tapatalk


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## Will_f

Jax said:


> Is it just the screw on the Damasko that is rusting or the steel itself? It's possible that they're not using the same metal in the screws as in the link and the case, right? The screws won't scratch like the bracelet will so I'd assume that they use different steel but I could be wrong.
> 
> Sent from my iPhone using Tapatalk


Dunno. I sent an email off to Damasko asking the question and will post the answer when I receive it.


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## Jax

Also what do you think of he damast coating vs. steel case for corrosion resistance? I'm guessing the damast will fare better but I don't know much about it. I do have one of each type of Damasko watch though so I'm curious. 


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## Will_f

Haven't tested it, but the Damast should be completely resistant to salt water corrosion, not to mention harder than any steel.


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## MrDagon007

Will_f said:


> If you live in a high humidity hot climate and you're buying a watch and expecting it to last for generations, gold, platinum, and 904L are probably your best options.


You forget a reasonably affordable alternative: titanium. Extremely corrosion resistant and non allergic. But scratchable!


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## Will_f

MrDagon007 said:


> You forget a reasonably affordable alternative: titanium. Extremely corrosion resistant and non allergic. But scratchable!


Doh!


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## MrDagon007

Will_f said:


> Doh!


Not to mention ceramic.


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## Will_f

MrDagon007 said:


> Not to mention ceramic.


Not as sure about ceramic. Too brittle


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## rafy1

Very interesting testing / review.

Thanks for sharing dear will.



Rafy.


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## louis

Will_f said:


> Dunno. I sent an email off to Damasko asking the question and will post the answer when I receive it.


A very good idea...yet !


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## Will_f

Time for another update. Generally, things have slowed down. I haven't added any bleach for at least a week and as it has slowly evaporated into the air, the reactivity of the bath has dropped. At this point it's probably less chlorinated than drinking water. None the less, the bronze has continued to be attacked. I'm pulling it from the experiment since I like the buckle and I don't want to completely destroy it:









The 316L SS links are holding up pretty well, though there are more signs of corrosion and you can see the surface is starting to look pretty pitted. The pin that started rusting is still rusting, but not at a super fast rate.















The Damasko screw surface appears to be a little etched.















The Damasko link appears to be about the same as last time, though from this position you can see that there was some significant pitting from when the link pin was installed. It seems to have stopped since the pin was pulled. The other pin and screw look fine other than the screw looking etched.


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## dukembla

It's getting in there. Great macro shots again.


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## CM HUNTER

Seems that the Damasko link is holding up the best out of the three (notice I didn't say screws in the link, but the link itself). Makes me wonder about the rusting issues some have had with their Damasko's. Maybe the rust is originating from a more common area but looks like it comes from a hardened one.


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## MrDagon007

In any case the steel bracelets will both demonstrate very good resistance in normal humid/salty environments since they hold up so well when soaked in the corrosive blood of the Alien monster.


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## Will_f

Ok, so I am pulling all the samples from the salt bath. At this point there appears to be a significant advantage to 316L. For those who haven't been following too closely, I pulled the Bronze buckle out last week due to significant corrosion. It was done. This week we have the 316L links and the Damasko links. On the 316L links, corrosion is there. I have no doubt that there is significant crevice / pitting corrosion occurring on the inside and when my link puller arrives from amazon I'll pull it apart and post any interesting pictures. in the meantime you can see corrosion is a problem:
















The Damasko link started showing corrosion around the second link pin so I pulled it apart:















The problems show on the close-ups... Significant pitting:
































When I get the 316L links apart we'll compare, but for now it looks like Damasko steel is not as corrosion resistant as 316L. This wasn't what I was expecting, but hey, that's why I did the experiment. What does this mean? Nothing if you live in a climate like Northern Europe or Northern US. It could potentially be a problem in SE Asia or areas where there is hot weather and high humidity. In any case, wait for an examination of the 316L pins first before you make up your mind.

Will


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## commanche

I just wanna say thank you for this experimentation. It's very informative and educational. Since I live is SE Asia, it'll also help with my decision on getting the next watch. Thanks again!


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## charger02

Very interesting indeed. I live at the beach in a pretty humid environment and wear my damasko everywhere daily. 


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## Okapi001

Will_f said:


> What does this mean? Nothing if you live in a climate like Northern Europe or Northern US.


Well, it also means you are paying more for something that in fact is not better (at least as far as corrosion is concerned).


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## MrDagon007

I live in hong kong, where climate is often quite humid, and no issue in the 1.5 year I have my damasko. Though we have pollution from shenzen, it is not as toxic here as the test bath...


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## Will_f

MrDagon007 said:


> I live in hong kong, where climate is often quite humid, and no issue in the 1.5 year I have my damasko. Though we have pollution from shenzen, it is not as toxic here as the test bath...


It's important to note that this test compared the corrosion resistance of Damasko steel to 316L and marine grade bronze. It does not tell you how it will fare on your wrist or how long you can reasonably expect any of those materials to last under normal use.

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## MrDagon007

Exactly my point.


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## harryst

Will_f said:


> It's important to note that this test compared the corrosion resistance of Damasko steel to 316L and marine grade bronze. It does not tell you how it will fare on your wrist or how long you can reasonably expect any of those materials to last under normal use.


Sir, you are a celebrity around here (for good reason, too). Thank you VERY much for the the time + effort (if everybody was like you... etc etc...)

I really hope that, like most celebrities, you get to enjoy the fringe benefits that are part of the package (eg you get laid a lot  *)

-- h

* admins, please don't ban me => this was a joke


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## Will_f

harryst said:


> Sir, you are a celebrity around here (for good reason, too).
> 
> I just hope that, like most other celebrities, you get fringe benefits due to your status (eg you get laid a lot )


I wish! Those days are decades behind me. If I were single maybe, but no such luck. Anyway, all the cute ones are literally half my age or younger.

Sent from my SM-T520 using Tapatalk


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## fishoop

Great thread, interesting experiment - this is what the forums are all about. No surprise the bronze was first to go but I would have guessed the Damasko would have held up better in comparison to the 316. The power of marketing I guess.

What's most interesting to me is the condition of that Rolex case back you presented - where did that Rolex live the majority of its life?


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## Will_f

fishoop said:


> Great thread, interesting experiment - this is what the forums are all about. No surprise the bronze was first to go but I would have guessed the Damasko would have held up better in comparison to the 316. The power of marketing I guess.
> 
> What's most interesting to me is the condition of that Rolex case back you presented - where did that Rolex live the majority of its life?


SE Asia. Thailand to be exact. It was my father in law's watch. I restored it so it looks like this now..









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## CM HUNTER

fishoop said:


> Great thread, interesting experiment - this is what the forums are all about. No surprise the bronze was first to go but I would have guessed the Damasko would have held up better in comparison to the 316. The power of marketing I guess.
> 
> What's most interesting to me is the condition of that Rolex case back you presented - where did that Rolex live the majority of its life?


Damasko marketing is based around scratch resistance. The ice-hardening process changes the metal entirely and the rust resistance has changed. In-depth information about this can be found in threads throughout this forum. You give up a little of something to gain a lot of something else, but Damasko has never stated that the advantage of their process focuses on anything other than scratch resistance.


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## fishoop

CM HUNTER said:


> Damasko marketing is based around scratch resistance. The ice-hardening process changes the metal entirely and the rust resistance has changed. In-depth information about this can be found in threads throughout this forum. You give up a little of something to gain a lot of something else, but Damasko has never stated that the advantage of their process focuses on anything other than scratch resistance.


That's a good point. Under real world conditions watches are subject to scratching more than anything else. Conditions that lead to corrosion seen in this thread is something most of us don't need to worry about. Although the example of the Rolex case back sure is interesting. (nice restoration, BTW).

A worthwhile trade off! Especially considering Damasko watches are for the active wearer and subject to some serious use.


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## DesertDweller

Hmmm. Anyone have a spare Damest-coated link to try the same test? Would that coating change the corrosion properties?

At any rate, thanks for the great empirical analysis, Will_f. Seems like my DA46 is quite safe here in the dry desert SW. Not too much moisture to worry about and the scratch resistance will protect from that gritty stuff we call air. b-) ;-)


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## Avo

CM HUNTER said:


> Damasko marketing is based around scratch resistance. The ice-hardening process changes the metal entirely and the rust resistance has changed. In-depth information about this can be found in threads throughout this forum. You give up a little of something to gain a lot of something else, but Damasko has never stated that the advantage of their process focuses on anything other than scratch resistance.


Not so. Damasko also claims superior corrosion resistance:


> This leads to the following results:
> 
> 
> Stainless steel AISI 304 (watch cases, not in common use): PRE-factor 20
> Stainless steel AISI 316L (commonly used for quality watches): PRE-factor 26-30
> Stainless steel AISI 904L (marine hardware, etc.): PRE-factor 35
> Stainless steel used for latest strategic developments of the German Navy, e.g. 1.3964/1.4566: PRE-factor 38
> Stainless steel DIN 1.4456 (high grade alloy used for medical implants): PRE-factor 52
> New Damasko stainless steel used for the DA 36/46: PRE-factor 50-52
> We think that this table perfectly illustrates the superior corrosion resistance of Damasko steel.
> By the way: Since most quality watches are made from 316L they don't offer real salt water resistance, so always make sure to rinse your sports/dive watch with fresh water after open water swimming or diving.


 https://www.damaskousa.com/technology-stainless.php


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## Will_f

Avo said:


> Not so. Damasko also claims superior corrosion resistance:
> https://www.damaskousa.com/technology-stainless.php


Brings up a good point. The links I tested were for a DK11. Not from a new DA36/46.

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## rationaltime

Will,

It was interesting. I like that you did the experiment. However, I think you
have demonstrated galvanic corrosion. I expect Damasko buys the stainless
link screws with a different alloy than the bracelet links they make. The same
is probably the case for the other bracelet manufacturer. Different alloys have
different electrochemical potentials. Normally it doesn't matter, but when you
put them close together in electrolyte you create little batteries. Though you
might say they have the same proximity when worn on the wrist, I wonder if
motion in the surf would sweep away the ion exchange that happens in the 
static test conditions. Anyway, I don't know what conclusions can be drawn
from this single test.


Thanks,
rationaltime


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## Will_f

rationaltime said:


> Will,
> 
> It was interesting. I like that you did the experiment. However, I think you
> have demonstrated galvanic corrosion. I expect Damasko buys the stainless
> link screws with a different alloy than the bracelet links they make. The same
> is probably the case for the other bracelet manufacturer. Different alloys have
> different electrochemical potentials. Normally it doesn't matter, but when you
> put them close together in electrolyte you create little batteries. Though you
> might say they have the same proximity when worn on the wrist, I wonder if
> motion in the surf would sweep away the ion exchange that happens in the
> static test conditions. Anyway, I don't know what conclusions can be drawn
> from this single test.
> 
> Thanks,
> rationaltime


Per Damasko, all parts of the bracelet are the same alloy.

Will

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## CM HUNTER

Key word to notice here that I purposely used was with a FOCUS on ice-hardening. Damasko also markets the special gaskets, crown tube, ball bearings for the bezel, etc... If you're going to claim that Damasko sold you on something through marketing, and that let you down, consider what that was. A Viton gasket could let you down too, doesn't mean marketing hype was at play.

Again, you give up a little corrosion resistance to gain scratch resistance. If that scaratch resistance process still puts that corrosion resistance level at one higher than other metals, then that's great, but it's still all based around the ice-hardening. From the results of this specific test, it doesn't look like there was any significance between the 316 damage and the damage on the Damasko metal. So, I wouldn't buy a Damasko expecting to get a superior rust resistant watch, but for scratch resistant toughness that they are known for, they are a go-to.


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## rationaltime

Will_f said:


> Per Damasko, all parts of the bracelet are the same alloy.
> 
> Will


Then there must be some other reason for the pattern of corrosion.
I wonder what that might be.

Thanks,
rationaltime


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## Will_f

rationaltime said:


> Then there must be some other reason for the pattern of corrosion.
> I wonder what that might be.
> 
> Thanks,
> rationaltime


I believe its crevice corrosion. Stainless steel in a salt bath creates little batteries when there is a variation in oxygen concentration. In crevices O2 concentration is low so Cl- ions in the bath pull Fe+ ions into solution and an electron moves through the steel to an exposed surface where O2 concentration is higher. That electron, combined with Fe+, O2 & H2O, produce Fe(OH)3, which accumulates near the crevice and is what you see as red rust.

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## dimman

Avo said:


> Not so. Damasko also claims superior corrosion resistance:
> https://www.damaskousa.com/technology-stainless.php


That isn't their ice-hardened martensitic steel that was tested here.

That is a replacement alloy being phased in. It is an austenitic stainless (so is 316L) that I believe uses manganese instead of nickel to create the austenitic phase. It is also a through-hardening steel. Through-hardening austenitic stainless steel is super-cool neato science stuff.

Rationaltime: the corrosion resistance displayed supports the PREN ranges of both Coridur and 316L. Coridur being slightly inferior to 316L with regards to corrosion resistance.

The new Damasko alloy looks to be able to achieve both superior corrosion resistance AND hardness over 316L. I believe this may be in response to some old rusting problems. I seem to remember Mike Stuffler posting on a rusty Damasko thread that Damasko was aware and correcting the problem (probably Coridur that was on the low range of the alloying element tolerances).


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## Robotaz

On one hand surprised, on the other not. Nice work.


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## WatchMann

Dimman said:


> The new Damasko alloy


 There is no "new" as far as I am aware. I believe the old copy from Damasko (where they speak of the DA36 in the future tense) made it sound as if something new was coming, however that copy is from when the steel was first coming to market. The steel has remained the same since then.


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## dimman

WatchMann said:


> There is no "new" as far as I am aware. I believe the old copy from Damasko (where the speak of the DA36 in the future tense) made it sound as if something new was coming, however that copy is from when the steel was first coming to market. The steel has remained the same since then.


Compare from here: Cases | Watch-Manufacture Damasko



> temperable martensitic stainless steels for use in watch case construction back in 1994. These steels are nickel-free, can be hardened up to 64 HRC or 800 HV and are therefore ideal for watch cases.


And from here: Stainless Steel | Watch-Manufacture Damasko



> For our new automatic models we chose an ultra-hard, highly corrosion-resistant austenitic stainless steel.





> We think that the above values may serve to make a qualitative statement with respect to the corrosion resistance of our new steel without any further need for explanation. We will shortly go into more detail concerning this steel that will be used by us in the future and is offered by us in fully hardened condition with a surface hardness of 1600 HV (stainless steel 316L: 190-210 HV).


The metallurgical terms indicate two different types of steel.

Plus the emphasis on 'new'.


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## WatchMann

Yes it was their new steel, back in 2006.


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## dimman

WatchMann said:


> Yes it was their new steel, back in 2006.


Well people have been claiming they use Coridur. Will's test supports that based on PREN and corrosion effects.

The 'new' alloy's corrosion performance suggest that it will be vastly superior to both Coridur and 316L. It also suggests a Sinn-like carbon diffusion on the surface rather than exclusively ice-hardened(1600 Vickers for the austenitic alloy vs 800 Vickers for the martensitic alloy).

Please confirm 100% from your supplier which watches use pressure nitrided 
austenitic steels and which use Coridur martensitic steel before the 'facts' get too muddy.


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## Clockworkblueorange

As far as I know the "new" promising steel usually referred as "Daminox steel" hasn't reached production yet. For some years now the focus at Damasko has been put on in house movement production and delayed the "Daminox" steel case development. Just look at the back of your watch, my new DA46 I got 2 weeks ago still claims Edelstahl 60 HRC (+/- 800 HV) and not 1600 HV as supposed for Daminox.


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## Alda_cz

This high-tech product of German engineering art is made in our watch manufacture along with all its components - "100 % Made in Germany" - "100 % Made in-house". Each connecting piece is manufactured separately and assembled by hand. The band constructed by specialists including the folding clasp is completely made of the same ice-hardened stainless steel as the DAMASKO case by specialists. In addition, the connecting elements are made of the heavy-duty material Titanium Grade5. Due to their extreme hardness and top toughness, the combination of these two high-tech materials make our steel bracelets virtually indestructible.
Price on request.

Manufactory Steel Bracelet | Watch-Manufacture Damasko

According to Christopher Damasko, the PRE factor their steel is 34.


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## Alda_cz

My EDC. 8 years old and...as new


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## dimman

Alda_cz said:


> This high-tech product of German engineering art is made in our watch manufacture along with all its components - "100 % Made in Germany" - "100 % Made in-house". Each connecting piece is manufactured separately and assembled by hand. The band constructed by specialists including the folding clasp is completely made of the same ice-hardened stainless steel as the DAMASKO case by specialists. In addition, the connecting elements are made of the heavy-duty material Titanium Grade5. Due to their extreme hardness and top toughness, the combination of these two high-tech materials make our steel bracelets virtually indestructible.
> Price on request.
> 
> Manufactory Steel Bracelet | Watch-Manufacture Damasko
> 
> According to Christopher Damasko, the PRE factor their steel is 34.


To get that number from Cronidur 30, he needs to over-value Nitrogen's role in PREN and use the MAXIMUM alloying element figures. Damasko uses 30x for Nitrogen content rather than the typical 16x. The 30x multiplier is supposed to be used on steels with a Molybdenum content of over 4% (Cronidur 30's Max Mo is 1.1%). Even with the inflated Nitrogen effect the MINIMUM PREN falls to 25.8. Using the more appropriate 16x multiplier the min-max is 21.6-27.6 very slightly less than 316L. Results here support that.

It's interesting that they chose Ti 6Al-4V for the screws*, given that different metals can increase corrosion in salt water via the electrolysis effect.

As a presumed metallurgist Damasko should know better. It seems the figures are being selected and presented by a marketing major rather than clear presentation of the science. A little disappointed by the obfuscation...

Either way, we've seen: A) that it's almost as good corrosion-wise as 316L (when the primary focus of the steel is high hardness) in a torture test, and B) largely irrelevant in everyday use anyways, since few people are washing their hands in bleach-spiked brine, and aside from an early rust-spitting issue on a very few they seem to perform fine in the real world.

* Will, any way to confirm this, as it is contrary to what Damasko told you? A magnet test will reveal if it's the same as the link. The sure-fire way to test for titanium is semi-destructive, though. Touch it on a bench grinder and titanium will spark a bright white, rather than orange for steel.


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## Trucido

Cool! Looks brand new! I need one of these...


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## Will_f

Dimman said:


> To get that number from Cronidur 30, he needs to over-value Nitrogen's role in PREN and use the MAXIMUM alloying element figures. Damasko uses 30x for Nitrogen content rather than the typical 16x. The 30x multiplier is supposed to be used on steels with a Molybdenum content of over 4% (Cronidur 30's Max Mo is 1.1%). Even with the inflated Nitrogen effect the MINIMUM PREN falls to 25.8. Using the more appropriate 16x multiplier the min-max is 21.6-27.6 very slightly less than 316L. Results here support that.
> 
> It's interesting that they chose Ti 6Al-4V for the screws*, given that different metals can increase corrosion in salt water via the electrolysis effect.
> 
> As a presumed metallurgist Damasko should know better. It seems the figures are being selected and presented by a marketing major rather than clear presentation of the science. A little disappointed by the obfuscation...
> 
> Either way, we've seen: A) that it's almost as good corrosion-wise as 316L (when the primary focus of the steel is high hardness) in a torture test, and B) largely irrelevant in everyday use anyways, since few people are washing their hands in bleach-spiked brine, and aside from an early rust-spitting issue on a very few they seem to perform fine in the real world.
> 
> * Will, any way to confirm this, as it is contrary to what Damasko told you? A magnet test will reveal if it's the same as the link. The sure-fire way to test for titanium is semi-destructive, though. Touch it on a bench grinder and titanium will spark a bright white, rather than orange for steel.


AFAIK, the connecting pieces are steel. Per Damasko, they're the same steel as the links. They're definitely not Titanium. The color is wrong and they've corroded slightly- something that would not have happened with titanium.

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