Spyderco Forums

Hi,

I've always had a prejudice against stainless steels, doubtless because of poor experience with low cost low quality blades. I also find no difficulty in looking after plain carbon steel for EDC or household duties, so even aside from that prejudice I have no problem putting corrosion resistance low on my priorities. So I was just wondering which of Spyderco's steels would be classed as non-stainless, and would offer advantages to someone who's prepared to forgo corrosion resistance and even baby them a little?

Thanks, Tony S

There's are a variety of really high performance non-stainless steels that Spyderco uses.

CPM Cruwear, CPM M4, HAP40, and CPM 10V being a few. Some of these steels have enough Chromium in them to provide a degree of corrosion resistance, but they are all far from stainless. Ive used both Cruwear and M4, and I am very impressed with both their performance and degree of corrosion resistance.

Dear Tony:

The easiest answer is to use our steel chart sorted by chromium content:

http://www.spyderco.com/edge-u-cation/S ... romium.pdf.

For martensitic steel's the threshold of stainless is typically considered 12% (some sources cite 13%), so everything near the top above SUS410 is non-stainless.

Stay safe,

Mike

Thanks for that. Interesting to see that ZDP-189 has just about the highest Cr, for some reason I thought it was non-stainless. Will keep an eye out for offerings with steels from the top of your list (already have something in HAP40 and K390).

aesmith wrote:Thanks for that. Interesting to see that ZDP-189 has just about the highest Cr, for some reason I thought it was non-stainless. Will keep an eye out for offerings with steels from the top of your list (already have something in HAP40 and K390).

At least in my experience ZDP-189 is "semi-stainless", at best. I've found that it rusts considerably more easily than VG-10, CPMS30V. It's not my cup of tea, as I value corrosion resistance, but you might like it.

Steels with less than 13% Cr content are considered stainless but in real life things are a little more complicated.

I dislike the term stainless steel. It is a spectrum, simple as that, and except for steels like H1 and LC200N there is no stainless steel. Chromium content is not a good measure either now that we have steels with ridiculous amounts of carbon. For example, S30V is considered stainless and I have had it rust on me quite easily and have even had instant staining from cutting up a banana yet it is considered stainless. On the other hand Cruwear seems more stainless to me than S30V but most consider it a semi stainless tool steel. Then you have ZDP which has tons of chromium and by that measure should be stainless but since it has an astronomical amount of carbon it is semi stainless at best. I have had brown spots appear on CTS204P when I put it away dirty for a month and it has a ton of chromium but also a ton of carbon. I also think that some of the other alloying elements have an effect on corrosion resistance although there is little info out there to support that. That is the only way I can explain the resistance to corrosion that I have seen in Cruwear or even HAP40. That is also the only reason I can explain the extreme resistance to corrosion that S110V has because with it's very high carbon content it is still very stainless. On the other hand Maxamet has gobs of other alloying elements including lots of cobalt but only a modest amount of chromium and it stained right away so who knows, maybe those other element don't do anything or maybe it depends on heat treat whether they make a difference or not. Even basic steels like 1095 which lack chromium can vary depending on heat treat. I have knives that are 1095 that rust almost instantly and I have others that seem to resist it quite well.

Anyway, it seems to be quite complicated in the end with varying heat treats, varying carbon contents and the possible effects of other alloying elements all coming into play.

If you like the behavior of carbon steels but also want something almost stainless then I suggest Cruwear.

Disclaimer; I am not a metallurgist nor a knifemaker but simply a geeky guy who likes knives...

So, the goal is to choose a steel that stains and corrodes easily? I must be missing something. I do tend to put a high value on corrosion resistance, but you will never see me asking for help choosing steels that have poor edge retention, or that chip easily.

I'm wondering why you don't just seek out what you want, rather than seeking to avoid what you don't put a high value on. Some stainless steels like S90V and S110V are simply outstanding in many respects.

And if you've had "poor experience with low cost low quality blades," what does that have to do with Spyderco products?

aesmith wrote:Hi,

I've always had a prejudice against stainless steels, doubtless because of poor experience with low cost low quality blades. I also find no difficulty in looking after plain carbon steel for EDC or household duties, so even aside from that prejudice I have no problem putting corrosion resistance low on my priorities. So I was just wondering which of Spyderco's steels would be classed as non-stainless, and would offer advantages to someone who's prepared to forgo corrosion resistance and even baby them a little?

Thanks, Tony S

Super blue and M4 are both non-stainless and require more attention and are considered very premium steels in the knife world. People tend to like them a lot despite their lack of corrosion resistance. They both offer a lot of benefits to someone who doesn't care about corrosion resistance, but they vary in their benefits. It's depends on what you want the steel to do ad how you want it to perform. Corrosion resistance may add a benefit you may not be aware of, though. The apex doesn't corrode as easily. A lot of people report that non-stainless knives lose their high sharpness even without use and it's heavily speculated that it's due to the apex of the edge corroding. Just food for thought and good luck with your search

Bodog wrote: Corrosion resistance may add a benefit you may not be aware of, though. The apex doesn't corrode as easily. A lot of people report that non-stainless knives lose their high sharpness even without use and it's heavily speculated that it's due to the apex of the edge corroding. Just food for thought and good luck with your search

Yep, this is a good point and one I would label as more than speculation. This phenomenon is easily observed in the knives I use on the ocean. I can easily keep the rust off of a steel like s30v when using it in the kayak but it requires daily sharpenings even if it doesn't get used.

With regard to ZDP-189, I once asked Sal about it and the effect of its high carbon content on the ability of its high chromium content to "do its thing." He confirmed that the 13%-ish chromium content was valid for blade steels with typical carbon contents. Once the carbon content is bumped to the ultra-high levels seen in ZDP-189, significantly more chromium is needed to offset it and achieve corrosion resistance. Although ZDP has 20% chromium, it is still more prone to corrosion than more conventional, mainstream stainless steels.

Stay safe,

Mike

So getting back to the OP, if you don't mind maintaining a carbon steel blade, go for M4 or super blue or hap40. If you are just looking for a high performing stainless, there are tons available from spyderco too, vg-10, s30v, etc... The prejudice may be because you haven't tried a modern stainless cutlery steel, if that's the case, you are missing out.

Thanks for all the comments. I do have some decent or half decent stainless knives, BD1 and Elmax, these are helping to dispel the prejudice.

Elmax can be great. Great all around stainless steel. I like it from my experience with the two knives I do have in it.

These topics always make me wonder why VG10 doesn't get the respect it should. If you want a do it all steel that's corrosion resistant, tough, easy to sharpen, that takes a very fine edge, it just about can't be beat for being a jack of all trades steel. It's easy to find other steels that out perform it in any of those categories but there is always a compromise.

D2 is right on the edge of being called a true stainless also, but with the high carbon content, the chrome is used up in combining with the carbon & the result is a blade which can rust in the wrong conditions. It's sort of like ZDP in this respect. The chrome is used up by the carbon. My Superblue Endura is still one of my favorites for sharpening & edge retention, I don't mind maintaining it since it looks ok with a patina & cuts extremely well. Easy to sharpen, amazing edge.

If I lived near the ocean I might change my mind, but living in the desert things aren't prone to rust, so I never have to worry about it.

Knutty wrote:So, the goal is to choose a steel that stains and corrodes easily?

Traditionally the stainless steels performed less than carbon steels. But these days cutting performance is similar, maybe even better with stainless steel according to Ankersons tests. But some carbon steels still have the edge in toughness, and can be easier to sharpen. If you aren't interested in these qualities then I don't know why you would choose carbon steel over stainless steel.

Thanks to Spyderco I now have a few knives with M4 steel and a few with S110V. I like M4 and in my tests it performs very well, although I know that S110V should outperform it in cutting power. But I still like to carry M4 sometimes for variety.

Thanks for all the comments. No my aim wasn't to choose a steel that corrodes as an aim in itself. Where I was coming from was that the very cheapest knives with non-stainless carbon steel blades significantly outperform stainless blades even on knives costing significantly more. It therefore occurred to me that the same might apply at a higher price point, do non-stainless high-end steels offer advantages over high-end stainless?

By the way, I've never tried VG10 as it's not been on offer with any of the knives I've looked at. As a rough informal and non-expert view I'd say that BD1 pretty much matches my carbon steel cheapies in ease of sharpening and sharpness, but is a little behind for edge retention.

It's interesting when I go to military trade shows. Invariably I'll get a few grizzled veterans who walk by the booth and ask if the knives are stainless steel. I'll answer that most of them are. Without breaking stride, they'll respond "stainless steel won't hold an edge" and keep walking.

We are all products of our own experience. Once something doesn't work for you, it takes a lot of it-does-work experience to outshine that. Fortunately, with Spyderco knives, you've got A LOT of different steels to choose from.

Stay safe,

Mike

aesmith wrote:Thanks for all the comments. No my aim wasn't to choose a steel that corrodes as an aim in itself. Where I was coming from was that the very cheapest knives with non-stainless carbon steel blades significantly outperform stainless blades even on knives costing significantly more. It therefore occurred to me that the same might apply at a higher price point, do non-stainless high-end steels offer advantages over high-end stainless?

By the way, I've never tried VG10 as it's not been on offer with any of the knives I've looked at. As a rough informal and non-expert view I'd say that BD1 pretty much matches my carbon steel cheapies in ease of sharpening and sharpness, but is a little behind for edge retention.

N690 seems to be very similar to VG10, and is available in a number of U.K. legal Spydies. These are excellent steels, and out-perform BD1 & 440c imho.