H1 steel? "100% corrosion resistant"?

What about Buck's 17-7PH?

17-7 PH is a chromium-nickel-aluminum precipitation hardening stainless steel. The alloy is used for high strength applications that require good salt-water corrosion resistance. Precipitation hardening alloys develop hardness at relatively low temperatures. This characteristic allows hardening with very little distortion, a property that is useful in aerospace applications.

Buck Knives uses 17-7PH specifically for knives that are designed for water-related activities. Most dive knives made today use Type 300 series stainless which has excellent corrosion resistance but low hardness and poor edge retention. 17-7PH is a good compromise between the higher hardness martensitic stainless steels that have relatively low salt-water corrosion resistance and Type 300 stainless steel. 17-7PH can be hardened to Rc54 -55 for reasonably good edge retention. The very high strength of 17-7PH makes it ideally suited for survival type knives.

Stainless Steels are "stain less", not "stain free". In certain environments they will certainly rust. For that reason, we recommend that you protect your investment by thoroughly rinsing the knife in fresh water after each exposure to a salt water environment and apply a layer of protective oil.

17-7 PH is used on Buck Knives new Tiburon water sport knife.

Carbon - .09 [Buck's page says ".7%"; .09 is the actual amount]
Manganese - .5
Silicon - .3
Chromium - 17.00
Manganese - .5
Nickel - 7.0
Sulfur - .002
Phosphorus - .02
Aluminum - 1.25
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I wonder if anyone has any experience with this?
 
I was about to explain PH steels when PhoulPlae and Keith posted .I was not aware that buck made a knife from this. I am glad you are all getting to love metallurgy.
 
Originally posted by mete
I was about to explain PH steels when PhoulPlae and Keith posted .I was not aware that buck made a knife from this. I am glad you are all getting to love metallurgy.
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I have had an interest in metallrgy for years. I am no expert, but I know enough to get me in trouble.

mete, what do you think of the PH steels as a material for knife blades?
 
VG-10 is exeptional in many areas, but if you live in a salt water environment, VG-10 will require a certain amount of maintenance. Such as dock working, living aboard, etc.

H-1 requires none (other than sharpening).

Also keep in mind a VG-10 blade probably has a 420 lock and a 440 spring, etc. Our H-1 Delica is using materials specifically designed to live in the salt water environment.

sal
 
I have no idea about edge retention of PH steels . The only thing I have in PH is a mobile radio antenna - you can wack trees without any problem.
 
Exxxcellent... thanks for the link on Age Hardening Keith.

I, too, have an interest in metallurgy and heat treating, but know about enough to stick my foot in my mouth once in a while. :footinmou

I work in the Petrochemical industry, and a good number of the control valves we spec employ a 17-4PH shaft. 17% chrome, 4% moly, hardened to provide strength...both rising stem and rotary valves.

I should have quizzed one of our staff metallurgists on what precipitation hardening was all about, but hadn't.
 
Originally posted by spyken
I have to disagree with that, respectfully. The knife is nice but the sheath can and will release the blade with a hard tug. That's unless the piece my friend showed me was defective. If you look at the retaining device (it's just a piece of plastic), I don't think it will support a full body weight.

And H1 does discolour/surface rust in saltwater, though a lot less than VG10 or ATS34. I would still rinse it in fresh water after use, wipe dry and use a tuf cloth on it.

That said, I think the knife is one of the nicest looking paddling knives in the market.
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I bought a Benchmade 100SH2O (dive knife with yellow handles, part serrated edge) from Knifecenter.com for $69.99. I had never handled the knife but it looked cool enough, so I got it.

First thing I noticed was just how well the yellow scales throw back light. They are very nearly luminous. Near dusk, they reflect so much more light than anything nearby that they seem to be glowing.

Second thing I noticed (well, tied with the first) is that the knife is smaller than I had been thinking it would be. No big deal. Still big enough to do its work.

I have had the knife on my vest when I've gone kayaking a couple of times in recent months. The sheath attaches to those square, slotted plastic buckles on a typical personal flotation device. It holds well there; however, I have not yet subjected it to the tumult of getting knocked around while kayak *surfing*. Hopefully the sheath will remain attached under such stresses, which is like going through a washing machine with several dozen tons of water in it.

Spyken is correct in that the extra little thumb-activated stud that augments the knife-retention ability of the molded sheath does NOT -- repeat NOT -- seem to me to do much difference when the knife is tugged out of the sheath. I would certainly not refer to it as any kind of "lock." I don't know if mine is a defective specimen, but given that Spyken describes the same sort of thing, I begin to think that it is endemic to all of these knives.

I have not subjected my knife to major stresses or prolonged salt-water immersion or even fresh-water immersion, nor have I stored it without rinsing with fresh water and drying. I also have not really used the knife. It has remained with me while kayaking as a "just in case" sort of thing. I touched up the edge with a Spyderco Profile as soon as I got it, and it is extremely sharp -- I would say as sharp as any other knife I have in say 440C or ATS-55 or even ATS-34 (my AFCK). Aiding its sharpness is the apparently very shallow edge angle. The knife seems wafer-thin at the edge, and able to take on a really good sharpening. I can't say how the edge will hold up to rigorous use, but as said here, it is rc58-60 or something, so why wouldn't it do as well as other steels of that hardness? I know that at the very least, since it's in its sheath on my vest razor sharp and mostly never used, it'll at least take care of the *first* emergency that comes up.

One thing that occurs to me, given how sharp I've got this knife, and its alleged resistance to corrosion, is, "Why don't they make many more knives in this steel? If the steel takes a sharp edge and resists rust even in a salt chamber, what does ATS-34 or any other steel have over it that they don't use H-1 for the AFCK, Griptilian, and others?"

Overall, I think this is a knife worth your getting.

---Jeffrey
 
58-60 HRC sounds quite high for a steel with such low carbon. Doesn't Boker's X-15TN claim high hardness and edge holding as well as being "100% corrosion resistant"? A head to head test would be cool here. I wonder how well 17-7PH compares to H-1 and X-15TN, etc.
 
Originally posted by Sal Glesser
VG-10 is exeptional in many areas, but if you live in a salt water environment, VG-10 will require a certain amount of maintenance. Such as dock working, living aboard, etc.

H-1 requires none (other than sharpening).

Also keep in mind a VG-10 blade probably has a 420 lock and a 440 spring, etc. Our H-1 Delica is using materials specifically designed to live in the salt water environment.
sal
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Sal,
While I wait for the ATR, patiently, I am now given another Spyderco delight to eagerly anticipate! When will we be able to obtain Delicas in H-1? I have to say that this is an awesome development, that you plan to make the Delica in H-1 as well as the springs, lock and pins. Leave it to you and Spyderco to come up with sensible designs and executions!

If I could make one request of Spyderco, it would be to come out with folders whose handle scales are held not with rivets/pins but with screws, a la the Military or titanium Salsa, etc. I believe that if a user buys a knife that turns out, for whatever reason, to need a little tightening (handle or blade pivot), he should be able to do so, and not be stuck with whatever the factory put together. It seems that many of the Spyderco models that have this to offer are of the higher priced variety. Any plans to make Delicas this way? I'd much appreciate it.

---Jeffrey
 
Originally posted by peacefuljeffrey

One thing that occurs to me, given how sharp I've got this knife, and its alleged resistance to corrosion, is, "Why don't they make many more knives in this steel? If the steel takes a sharp edge and resists rust even in a salt chamber, what does ATS-34 or any other steel have over it that they don't use H-1 for the AFCK, Griptilian, and others?"
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The main reasons would be that these steels will not hold an edge as well as the better martensitic steels and they cost more. Nickel is the most expensive alloy that is added to stainless steel. Even though $70.00 is not much, this knife could have been made less expensive if the more commonly used 400 series steels had been employed.
 
Well... we are[/] talking about people who will spend $250 and more for a folder like a Sebenza... If the Benchmade Dive Knife cost $70 for H-1 steel, what would it have cost with 440C? Twenty dollars less? Ten? Thirty?

What I'm talking about is spending a little more, if indeed it costs that much more, and having a knife that will not rust, as opposed to one that surely will when exposed to the same nasty environments.

I've had quality knives show spots of rust after just part of an afternoon in a back pocket on a hot day. If that folder were H-1, I presume I would have no worry over such an occurrence. To me, that's worth adding 10-30% to the price of the knife.

I am EAGER for the H-1 Delica, as well as H-1 in any other knife. If the hardness is around 60rc, why would this steel "not hold an edge" as well as another stainless steel of the same hardness? I would have thought that once we are talking equal hardnesses, the remaining factor of holding an edge would have to do with thickness of the grind on that edge...

---Jeffrey
 
Hi Jeffrey. H-1 comes hard from the foundry. Harder to work it. Drilling, reaming, etc.

We couldn't get Rc60. Even 58 is tough at this time but achievable. Benchmade's piece Rc'd at 58.15 average.

Our Delica uses H-1 for lock and blade. other corrosion reistant materials (including 17.7 for other parts.

H-1 is a fairly new steel and still has much remaining to learn. We're not going to run out and make everything in H-1. Edge retention, in our tresting was not as good as 440C, ATS-34 or VG-10 in plain edges. Serrations were very good.

sal
 
Sal,

Is the H1 Delica replacing or supplementing the VG-10 Delica?

Regarding aging and nitrogen-containing steels,

Doesn't Busse have some product with beechwood aging? Would that be INFI or something else? ;)
 
Even though my vg-10 delica that I bought just over a month ago is going across canada(on it's way to ontario from alberta), just because it didn't work for me anymore(getting picky now after ones like millie, lumto and temperance)... I'll grab one of the h-1, if for nothing more than a water knife.
 
Sal, it's great having you here and answering questions. I appreciate you taking the time to do so.

Thanks for the insight into H-1 and the Spyderco experimentation with it. We're all looking forward to cool stuff to come.

If I could ask you one additional thing...
You have mentioned on this and other occasions "Spyderco's edge-retention testing" and also sharpness testing, and it makes me wonder what objective tests there are that you do to determine both sharpness and edge-retention. I have always thought of sharpness -- when you're comparing sharp knives to sharp knives -- to be a sorta subjective thing. It's not?? :eek: So I'd love to know how the pros determine these things.

Thanks,
---Jeffrey
 
Hi Jeffrey, we use a CATRA to test with. We have a regular tech that is always testing so we have a fair amount of data.

The CATRA "Sharpness" test is measuring the first 3 cuts in millimeters of cut. A very sharp knife will initially cut more. It's not ideal, but very consistant and certainly the best we've seen to date.

Edge retention is the total card cut in millemeters after a specified number of cuts. It is also very consistant.

hope that helps.

sal
 
Does anyone know how tough H1 is? I mean do it have more impact toughness than martensitic stainless steel (CPM30V or any other) or less? Amount of carbon would suggest more, amount of cromium would suggest less, being austenitic?
 
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