Steel that won't rust

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faceplant

Joined
Nov 20, 2005
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18
has anyone heard of Spyderco's new H-1 steel. it supposedly won't rust because they have removed all carbon from the blade and used nitrogen instead. can someone tell me how this will effect the knife besides the not rusting qualities
 
Welcome to the forums.

did you try a search? H-1 is an alloy using nitrogen in place of carbon. it is work hardened, meaning that by using the knife and sharpening it, it actually gets harder at the edge. I find that it is easy to maintain, make sharp, and keep sharp, and my atlantic salt is only a few days old.

pete
 
They haven't removed all of the carbon, but they have removed a lot of it. There is another alloy, X15-TN, that is similar. You'd think that with most of the earth's atmosphere composed of nitrogen that nitrogen alloys would be alot more common.
 
As I have studied Nitrogen in steel, it gives a lot of beneficial effects when used at the proper levels. Infi steel, Hitachi Blue, and S30V all benefit from Nitrided steel in strength, wear resistance, corrosion resistance, and hardness. Nitrogen unlike Carbon has the ability to bond exta-tersially crystal to crystal. This Nitrogen bond allows for sharpening through the crystals of steel. This Ferro-nitride is technically a ceramic because of this extratersial bonding ability. The usable alloy amount of Nitrogen is below its solubility and easily added at smelt. Look for expanded uses of Nitrogen steels in cutlery, and in industrial applications.
 
H-1 is great stuff and used in many scuba diving knives around where I live. It doesn't even need to be rinsed off with fresh water after a dive. Great edge holding also. I wish all my knives were made of it.
 
About 2 months ago I lost my Spyderco plain edged Merlin in the Wetlands where I work a lot. I got so use to using a plain edged Hawkbill for a "companion knife" to the C-44 Spyderco big Dyad that I carry everyday. So I got a Spyderco TASMAN plain edge made from H-1 blade steel. I was hesitant to get it at first because I had heard that H-1 blade steel was not as durable as ATS-55 or VG-10. But I have been very pleasantly surprised and the yellow handled TASMAN has now become a great companion knife.

I sharpen it quite frequently because of the "work hardening" properties of the steel. Believe it or not it holds an edge almost as good as the Merlin used to. I will no longer hesitate to use any Spyderco knife with H-1.

It's kind of funny in a way because when Benchmade introduced their 100S H2O dive knife they first came out in H-1. Now the newer ones have the X-15 TN that the one brother made reference to. I wonder why BM made the switch :confused:
 
Benchmade has promoted the idea that X-15 has better edge retention than H1 and this is worth the loss of corrosion resistance.

-Cliff
 
In our testing, X15Tn did not rust at all. In that area, it was excellent. Boker uses X15Tn as well with good success.

sal
 
Sal - So why did you go with H-1 rather than X15Tn? Obviously you found something to recommend the former over the latter.
 
Hi Mike,

Everyone says "ours is better" so I won't bore you with that. :rolleyes:

Let's just say that we felt it served our needs, niche and customers closer.

sal
 
I have read now many times that nitrogen replaces carbon and this is why it doesn't rust...but I think this is simply not correct. Now this may be a bit off topic, since this is really of no consequence to the ELU but for those interested, maybe we can get a discussion going:

A conventional steel is hardened due to a transition from austenite to martensite, due to the carbon that is dissolves in austenite is not soluble in martensite and hence occupies interstitial spaces in a stressed matrix. Nitrogen is small, and thus should induce less stress than carbon and even combined carbon and nitrogen together make up about 0.25%....not enough to get to the high hardness measured for H-1. So I don't think that nitrogen replaces anything. I am sure it has many beneficial aspects, such as Ed Schempp noted but I very much doubt that it replaces carbon in the sense that it is responsible for the hardening as carbon is in conventional steels.

Since H-1 is a precipitation hardening steel, something would have to preciptiate. I am sure that nitrides as well as carbides are precipitating, however, H-1 has two elements in large quantities that are often overlooked while everyone is focussing on nitrogen. H-1 contains large amounts of Ni and Si. I suspect that they are actually the reason for the precipitation hardening process, Ni by forming intermetallic compounds that precipitate and have no idea what this much silicon could be doing in a steel.

Non of this explains where the corrosion resistance stems from, the hardening, yes, but not the corrosion resistance. And I have no earthly idea, maybe it is due to the nitrogen, but not likely by "replacing carbon".

Anyways, just musing.

For the ELU only one thing is really relevant: H-1 is great stuff :thumbup: .

P.S. Anyone know where I would find some bar stock of H-1?
 
Carbon in the matrix makes the corrosion resistance decrease, while nitrogen in the matrix does not, I believe that nitrogen might actually increase corrosion resistance as well, but I'm not as sure on that one, so when nitrogen is the element in the matrix to create hardness, then corrosion resistance increases. Nitrogen acts quite a bit like carbon in steel. There are other reasons why H1 is so corrosion resistant, however.
 
Here is a cache of Benchmades comments on H1 vs X-15 :

http://72.14.207.104/search?q=cache...tbb/ultimatebb.php?ubb=get_topic;f=1;t=007338

Nickel is the main reason it is age hardening, it forms precipitates such as Ni3Mo which form at dislocation points in the low carbon martensite and pin them thus increasing the strength, silicon strengthens through solid solution among other things. Nitrogen has a wealth of effects on corrosion resistance, some of the exact processes by which it does this are currently debated. Nitrogen dissolution can form ammonia which can lead to an increase in PH and a resulting repassivation of the surface of the steel. It can also inhibit the formation or growth of Cr rich carbides which maybe what people mean by replace carbon as nitrides will form instead during precipitation. If carbon ties up chromium that percentage of the chromium does nothing for corrosion resistance which is why it is important that it be very low, or the ratio low anyway. Just look at the corrosion resistance of something like 420J2 vs ATS-34.

-Cliff
 
How specifically does carbon in the matrix make corrosion resistance decrease? (Edit: Nevermind. Thanks Cliff)
 
I think (though we're treading in to some waters I'm not completely sure of), that not only does carbon steal chromium in carbides, but carbon itself in the matrix decreases corrosion resistance, I think that's why they go for as low carbon as possible with austenitic stainlesses.
 
Carbon has a low solubility in alpha-ferrite, 0.008% at room temperature. It will form compounds readily as soon as it has the ability to become unsupersaturated and rapidly diffuses of the martensite when tempered for example. It could have an effect on the bond strength of the iron in the BCC structure which would increase the ability of oxygen to oxidize it possibly. However the major concern with carbon and corrosion resistance is that it will readily suck out any chromium if given the chance. For example at 700C 0.06% carbon steels will precipiate chroimum carbides in just two minutes and the steel will then becomes very weak to intergranular corrosion at the grain boundries as these are the cites of precipitation and will have become locally depleted of chroimum. This is why stainless steels are not stainless when annealed, the chroimum is in the form of carbides having passed through those temperatures where it carbides readily during the annealing.

-Cliff
 
Thanks, Cliff. So my guess was right that Nickel and Si are at least as important for achievable hardness of H-1 as nitrogen is.
 
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