Lc200n and corrosion resistance...new observations

[Surfingringo]

Sooooo, as of yesterday, I have some new observations on lc200n. I have been using this steel for a couple of years now and I have been testing it HARD for the last year. By testing hard I mean I have been abusing it in an attempt to get it to fail in various ways. Mainly by purposely subjecting it to extreme levels of corrosive environment.

What this means is I have been trying (or rather not trying through neglect) to create corrosion on the steel. I have various knives in this steel. Some from Spyderco and some customs. My normal routine is probably 10x more likely to make a knife rust than what the average land bound user puts an EDC through but to try to test the limits of this steel I have taken things much further. I have lc200n knives that NEVER see a drop of fresh water. I purposely leave them covered in salt and blood everyday. The fixed blades live inside kydex sheaths. Some on the deck of the kayak and some in compartments. They stay in there 24/7 (some laying in shallow pools of saltwater, without a rinse and bake in the tropical heat. (I have done the same testing for years with H1) The point of all this is to get to the truth about the level of corrosion resistance of these steels. I have been subjecting them to a level of abuse and neglect that leaves me confident that if I can't create corrosion in them then it's simply not going to happen.

What I have found after years of this type of "abuse" is that H1 is a fully rust proof steel. I have never been able to make the steel corrode in any way. Yes, after months of this level of exposure one can see some corrosive bleeding from the hardware or the residue corroding on the blade etching but nothing, and I mean NOTHING, I have done has been able to cause any corrosion or rust on H1.

So a year ago i started testing lc200n and I have put it through the same rigorous conditions and I have found it to also be 100% corrosion proof...until just now.

I have multiple fixed blades in this steel and one of them lives in a compartment in my kayak in its sheath, resting in saltwater residue. I have not used that particular knife for a few months and it did some fish work on the last outing. Yesterday when I pulled it from the sheath I noticed a small spot at the tip about the size of a pin head. I wiped it off thinking it was probably dried blood but it didn't wipe off as easily as I thought. When I scraped it off with my fingernail the feel of it let me know that it might actually be a spot of corrosion. I was surprised but interested.

When I got back home I brought the knife in and examined it with a 12x loupe. What I found was indeed a tiny spot at the tip where some corrosion had occurred. As I said the visible red spot was about the size of a pinhead but once that was wiped off (easily) then there was nothing visible to the naked eye. Under magnification however, I could see some VERY tiny pitting on the steel.

So I have been able to cause the most minor levels of corrosion in lc200n, but the more interesting question is how? I do not have the answer to that yet. I am reticent to believe that this is a result of exposure to saltwater. I say that because I have multiple lc200n knives that have lived under the exact same conditions and have been there much longer than this one. NONE of them have ever shown ANY corrosion and even in this example the corrosion was isolated to one tiny spot. That is not consistent with the idea of the steel corroding as a result of the overall saltwater exposure of the entire blade.

The two conclusion I can think or are that

A) something in the Heat treat left a tiny area of the blade susceptible to corrosion. I am not a HT expert but this explanation seems rather unlikely to me.

B) That part of the bade was left exposed to something far more corrosive than saltwater. This is the most likely scenario and the culprit is likely bile and acid from a fish's belly that was left on there for months.

At this point I am only guessing but what I can say now is that it is possible to create rust/corrosion on lc200n. I REALLY hope this post is taken in context. I hope this does not get read and repeated as "surfingringo says that lc200n is rust prone!" :rolleyes: In the interest in keeping this in context let me give a numerical ranking. If we were ranking steels on corrosion resistance and H1 were a 10 then the next closest steel I have tested is s110v and I would give it about a 7. With those numbers as context, I would call lc200n a 9.95. No normal human is going to make this steel rust. Trust me, It's as close to rustproof as a steel can come but when it comes to being fully corrosion proof I still have to give a slight edge to H1.

What does that mean about my thoughts on using the steel? Not much really. I still prefer lc200n to H1 for my plain edge knives by a wide margin. I get much better performance out of the edge and he steel is rust proof to the point that I am totally comfortable still leaving them on my kayak in their salty sheaths. The only change I might make is giving the knives a quick rinse in saltwater after i clean fish on the kayak. Honestly though, I'm not even sure I will do that. I am rather curious to see if I can get this to happen again and I am not convinced that I can. I will keep trying though.

[Surfingringo]

**For the record, (assuming that stomach acid was indeed the issue) I have left H1 exposed to this type of acid MANY times and never seen any corrosion.

[elena86]

The vast majority of users will not submit their knives to such an "abuse", not by far.I say that LC200N is rustproof enough for most.It would be very interesting to see if H1 will prove itself as the "real rustproof steel".No matter what, I am a huge fan of H1 in spyderedge and the fact that LC200N has better edge retention than H1 in plain edge is irrelevant for me.Keep up this interesting "survey" Lance :cool:

Marius

[rodloos]

Is it possible that the pin-head-sized spot of corrosion was due to some impurity in the LC200N? I don't know how LC200N is made, just wondering if that could explain why you only saw the corrosion on that one tiny spot but not elsewhere on the knife or on your other LC200N knives?

LC200N does appeal to me a lot since on a plain edge knife it holds its sharpness longer that H1.

[Bloke]

Very informative Lance. :cool:

I'd say this is a glowing endorsement of LC200N's corrosion resistance and I don't see how anyone could misinterpret your words. :)

[NickShabazz]

Out of curiosity, have you subjected any other steels to the same treatment, as a sort of control?

[npad69]

thanks for the detailed report sir gringo

[gmhauy]

Is it possible that the pin-head-sized spot of corrosion was due to some impurity in the LC200N? I don't know how LC200N is made, just wondering if that could explain why you only saw the corrosion on that one tiny spot but not elsewhere on the knife or on your other LC200N knives?

LC200N does appeal to me a lot since on a plain edge knife it holds its sharpness longer that H1.

I was going to ask the same question: is it possible that a tiny ferrous impurity remained embedded in the steel and got to rust given the right circumstances?
That would be a defect in the fabrication of maybe that batch of LC200N, but would not bear on the rustproof quality of the LC200N itself?

Gerard

[SF Native]

Is it possible that the pin-head-sized spot of corrosion was due to some impurity in the LC200N? I don't know how LC200N is made, just wondering if that could explain why you only saw the corrosion on that one tiny spot but not elsewhere on the knife or on your other LC200N knives?

This is exactly what I was thinking. Maybe that one spot had a little more carbon, a little less nitrogen and chromium. Manufactured items are not perfect. Such a small imperfection maybe.

[Surfingringo]

Out of curiosity, have you subjected any other steels to the same treatment, as a sort of control?

Hey nick, I have done this testing with most every steel I use. Of course I don't leave normal stainless steels in there for months and years like I do with H1 and Lc200n as it would turn into a red mound of rust within a month or two given that level of exposure. I have tested them all to see how they hold up though. Every steel other than Lc200n and H1 will start to show corrosion and spotting by the end of a full day on the kayak. They can't even really be compared to steels like Lc200n/H1 when it comes to corrosion resistance. It's like comparing steel to titanium. As an example, the best stainless I have found for corrosion resistance is s110v but even that will start to show spots after the end of a long day. I have left s110v in that compartment overnight (where I leave my salts for months on end) and it is well spotted by morning.

More importantly though is what happens to the edge/apex. Because the edge is so thin, that is the first place that gets attacked by corrosion. I have gone out in the morning with a screaming sharp s110v blade that will treetop hairs and come in 8 hours later without even using the knife and the edge will only scrapeshave. That's what I love about Lc200n/H1. I can leave them in the boat indefinitely without ANY edge degradation. Even the Lc200n knife that showed the one odd little spot had lost none of its bite and was every bit as sharp as it was 3 months before when I threw it in that wet and salty compartment. That is another indication to me that there is some anomaly at play that caused the spot. If Lc200n was corroding AT ALL due to saltwater exposure then the edge would have fallen apart long ago.

My theory on the pinhead sized spot is it was either stomach acid or an impurity in the steel. (Maybe bluntcut will do some testing and we will learn some more.) Like I said though, I have left H1 exposed to that same type of acid and never seen any corrosion. Now, if I looked closely with a loupe, I might be able to find some tiny spots where that acid had caused some microscopic pitting over the years but I have never seen any red ferrous oxide formation on H1 that was caused by something interacting with the H1 steel itself.

[Doc Dan]

I would like to see Spyderco start making some affordable knives in LC200N like they do with H1. We could all test it, that way.

Lance, what would you compare the edge holding to?

[Surfingringo]

I would like to see Spyderco start making some affordable knives in LC200N like they do with H1. We could all test it, that way.

Lance, what would you compare the edge holding to?

Probably something like 8cr13, but don't quote me on that. I've got a Byrd knife here so I might try to do some testing later this week on rope. I tested it on rope a couple of years ago with H1 and s30v and it fell right about in between the two. Edge retention is sufficient for a work knife and it sharpens up easy. It's a much fairer trade off than what you get with pe H1.

[murphjd25]

Thanks for the update Lance! How's that Spydiechef treating you?

[bluntcut]

I concur with Lance. My test zfinit blades (59, 59.5, 60rc) have similar edge retention to 52100 and aebl at same hrc. However this level of edge retention is not good enough for my liking, unless somehow I manage ht it to 62+rc (failed multiple times ). It has best corrosion resistance among steels I've tinkered.

I would like to see Spyderco start making some affordable knives in LC200N like they do with H1. We could all test it, that way.

Lance, what would you compare the edge holding to?

Probably something like 8cr13, but don't quote me on that. I've got a Byrd knife here so I might try to do some testing later this week on rope. I tested it on rope a couple of years ago with H1 and s30v and it fell right about in between the two. Edge retention is sufficient for a work knife and it sharpens up easy. It's a much fairer trade off than what you get with pe H1.

[Evil D]

Lance you've probably mentioned this at some point but how has edge degradation been in salt vs other steels? I understand this to be an issue especially with carbon steels.

[ohcyclist]

This real world data is very helpful. It makes me even more interested in the new Caribbean models coming out. Have you tried Lc200n in an SE format?

[Surfingringo]

Lance you've probably mentioned this at some point but how has edge degradation been in salt vs other steels? I understand this to be an issue especially with carbon steels.

Hey Dave, I'm not sure if I understand you. Are you talking about edge degradation due to corrosion? If so, as I said in my OP, every other stainless steel I've tested will start to lose its highest levels of sharpness purely from corrosion within 8 hours...most quicker. H1 and lc200n show zero edge degradation from corrosion, even after months of 24/7 exposure.

[Evil D]

Lance you've probably mentioned this at some point but how has edge degradation been in salt vs other steels? I understand this to be an issue especially with carbon steels.

Hey Dave, I'm not sure if I understand you. Are you talking about edge degradation due to corrosion? If so, as I said in my OP, every other stainless steel I've tested will start to lose its highest levels of sharpness purely from corrosion within 8 hours...most quicker. H1 and lc200n show zero edge degradation from corrosion, even after months of 24/7 exposure.

Yep that's exactly what I was wondering, I must have missed that in the OP.

[Surfingringo]

Lance you've probably mentioned this at some point but how has edge degradation been in salt vs other steels? I understand this to be an issue especially with carbon steels.

Hey Dave, I'm not sure if I understand you. Are you talking about edge degradation due to corrosion? If so, as I said in my OP, every other stainless steel I've tested will start to lose its highest levels of sharpness purely from corrosion within 8 hours...most quicker. H1 and lc200n show zero edge degradation from corrosion, even after months of 24/7 exposure.

Yep that's exactly what I was wondering, I must have missed that in the OP.

yeah, that is actually the most important quality of these steels. I could take some basic precautions and keep the rust off of a steel like s110v even in my environment but I would have to resharpen every single day whether I used it or not.

[Evil D]

Lance you've probably mentioned this at some point but how has edge degradation been in salt vs other steels? I understand this to be an issue especially with carbon steels.

Hey Dave, I'm not sure if I understand you. Are you talking about edge degradation due to corrosion? If so, as I said in my OP, every other stainless steel I've tested will start to lose its highest levels of sharpness purely from corrosion within 8 hours...most quicker. H1 and lc200n show zero edge degradation from corrosion, even after months of 24/7 exposure.

Yep that's exactly what I was wondering, I must have missed that in the OP.

yeah, that is actually the most important quality of these steels. I could take some basic precautions and keep the rust off of a steel like s110v even in my environment but I would have to resharpen every single day whether I used it or not.

That's really interesting. I wonder how much of that effects us non salt water folks. Is there a line where the edge retention of something like S110V makes up for what it loses to edge corrosion compared to LC/H1? Or are you just operating mostly at peak sharpness anyway?