Steel testing underway...

[shqxk]

It would be great to move this to testing section. IMO this thread is far more valuable/creditable than the bias robe cutting thread :foot:

 

[aarongough]

The corrosion section of the testing is now underway. I'm surprised how well A2 and CPM3V are doing so far, much much better than O1.

I hadn't really played too much in the past with the different tool steels, it's a pleasant surprise to discover that there's so many differences between them!

 

[aarongough]

Ok guys,
I have concluded the corrosion test. I figured it wasn't worth going much beyond 24 hours as I'm more interested in the testing reflecting some real world neglect, as opposed to a knife that's been left in the bush for a year...

Basically I put all the blades on a piece of aluminum foil, then a piece of waxpaper on top of that to prevent any possible issues with galvanic corrosion. I then sprayed the whole batch with plain water from a spray bottle every few hours. They were kept wet the entire time expect for just in the early morning when I forgot to get up and re-spray them...

So here we go!

Best
440C
CPM154
CPM3V
A2
O1
Worst

The difference between O1 and A2 was huge. The O1 pitted badly and almost immediately. The A2 had only minor pitting and that took quite a while to develop. The difference between A2 and CPM-3V was significant, but nowhere near as big a leap. The CPM3V only has 3 small pits on it after cleaning, whereas the A2 has about 8. The CPM154 formed small amounts of rust on the sandblasted part of the blade, as well as on the reverse side in the engraving. The 440C simply refused to rust, there wasn't a spot on it anywhere.

I was surprised that 440C beat CPM154. Perhaps saltwater would affect them differently, but I'm not hugely interested in testing that.

The top side of each blade was polished to around 400 grit, then finished with a 800-1000 scotchbrite belts. I deliberately left the finishes much less than perfect as I wanted to test what would happen after a user had scratched up and used the blade. The bottom of each blade was finished to 120 grit and left there.

Before:

After 24 hrs (top which is finished somewhat finely):

After 24 hrs (bottom which is finished to 120 grit):

Then I wiped each of them down with a green scotchbrite to differentiate between pitting and just surface rust. You can't see it very well but the A2 blade has about 8 minor spots of pitting. The CPM3V only has 3. The O1 is covered as you can see, and the other blades were not affected at all.

Personally I'm somewhat surprised that A2 and O1 are so different purely because I had never given the subject of corrosion resistance in non-stainless steels much thought. I have found O1 to unmanageable in kitchen blades (at least the way I treat them) but I would guess that A2 or CPM3V would both be fine for my use.

 

[Don Hanson III]

Good test, but no surprise here. The more chromium a steel has the more corrosion resistant it is. A2 and 3V have enough to make a difference, 01 not so. It's also known that 440C has more stain resistant than most any stainless blade steel.

We use simple high carbon blades in our kitchen and they only need to be wiped off and not let sit wet. Corrosion is not a problem at all.

 

[Huntsman Knife Co. LLC.]

Nice to see some stain resistance testing! Looks like 3V holds up to its reputation to pit instead of surface rusting. A fine finish results in it being very stain resistant in my experience.

Alot of guys don't think stain resistance is overly important in steel selection and I will admit that its usually my last point of concern but its very nice to have a knife you can put in your sheath wet and not have to worry about it coming out caked in rust.

 

[Mudbug007]

Thanks for doing all these tests! I'm not surprised that forge 01 did so well. IMHO most makers cook their 01 too hot too long. Some of the first blades I made were from 01 HT in a grass burner forge and quenched in warm ATF. Yeah, I did it 'wrong' but those first dozen or so knives went right out to the field and I'm still getting rave reviews about how well they hold an edge. Several are in the hands of hog hunters who are telling me they're skinning an average of 3 hogs before touching up their blades.

On the other hand, I made some from CPM 154 and sent them off to be HT. I was really hoping this would be the steel to end all steels! But after using them in the Kitchen and hearing what others said about their experiences with my Kitchen knives, I was far from impressed with 154. In fact, I was really disappointed. Luckily, there's something called 52100 that really will hold a keen edge! Just don't over cook it!

Would love to see this test performed again with 52100, W2, D2 and CPM 35vn thrown into the mix

 

[aarongough]

Good test, but no surprise here. The more chromium a steel has the more corrosion resistant it is. A2 and 3V have enough to make a difference, 01 not so. It's also known that 440C has more stain resistant than most any stainless blade steel.

We use simple high carbon blades in our kitchen and they only need to be wiped off and not let sit wet. Corrosion is not a problem at all.

It shouldn't have surprised me, but it kind of did. The reason is that I've only ever made knives from O1 and 440C in the past, and I see now that they're kind of polar opposites. From a user perspective: I've only really ever bought stainless knives, so I've never had much chance to see the 'shades' of corrosion resistance available if that makes sense.

I'm probably just lazy and too used to stainless in the kitchen. I made myself a blade from O1 for kitchen use, and that thing is pitted to hell. Granted I also screwed up by not finishing it correctly, so I'm sure it would perform better with a finer finish. It was meant to be a prototype and therefore never really got finished. At some point I will have to put a fine polish on it and see what the difference is like...

 

[aarongough]

Nice to see some stain resistance testing! Looks like 3V holds up to its reputation to pit instead of surface rusting. A fine finish results in it being very stain resistant in my experience.

Alot of guys don't think stain resistance is overly important in steel selection and I will admit that its usually my last point of concern but its very nice to have a knife you can put in your sheath wet and not have to worry about it coming out caked in rust.

I honestly really wish that I could offer a stainless blade with performance similar to what I'm seeing from the A2... I'd like my knives to be low maintenance or zero maintenance if possible, but it seems that may not really be possible while still maintaing the best performance. That was the hope that I had for CPM154, but it has turned out not to be.

I agree with the idea that it's nice to be able to just 'use' a knife without having to think too much about it, rather than having to fawn over it constantly...

 

[aarongough]

Thanks for doing all these tests! I'm not surprised that forge 01 did so well. IMHO most makers cook their 01 too hot too long. Some of the first blades I made were from 01 HT in a grass burner forge and quenched in warm ATF. Yeah, I did it 'wrong' but those first dozen or so knives went right out to the field and I'm still getting rave reviews about how well they hold an edge. Several are in the hands of hog hunters who are telling me they're skinning an average of 3 hogs before touching up their blades.

On the other hand, I made some from CPM 154 and sent them off to be HT. I was really hoping this would be the steel to end all steels! But after using them in the Kitchen and hearing what others said about their experiences with my Kitchen knives, I was far from impressed with 154. In fact, I was really disappointed. Luckily, there's something called 52100 that really will hold a keen edge! Just don't over cook it!

Would love to see this test performed again with 52100, W2, D2 and CPM 35vn thrown into the mix

I'm very sure that I'll perform more tests with different steels in the future, but it probably won't be for a while.

Next week I'll be doing more testing, but all on A2. I want to do some different heat-treats and test the blades against each other to make sure that I'm not missing out on any potential in the steel. Should be fun.

I sure am looking forward to getting some knives out the door soon though, I'm sure my customers would appreciate it too

 

[Don Hanson III]

I grew up in a house with all carbon steel cutlery and the men folk all carried carbon steel pocket and hunting knives. Stainless knives rarely entered the picture and when they did it was always a disappointment. I know there are better stainless steels now, but I like blades that change color with use.

 

[Willie71]

This is an O1 chef's knife after 4 months of daily use. This was the 1st knife I made with a known steel, after giving up on scrap steel.

 

[aarongough]

This is an O1 chef's knife after 4 months of daily use. This was the 1st knife I made with a known steel, after giving up on scrap steel.

Nice! I think the main part of the problem with the knife that I made for myself was that I didn't finish it to a high enough polish. I'm sure that with a bit more finishing it will be much more stain resistant. That blade was intended as an experiment to see how hard it was to finish after heat-treat... Turn out if you're finishing by hand you shouldn't leave a blade at 60 grit! Now that I've got the grinder I'm sure that re-finishing that blade is much more practical.

 

[aarongough]

I grew up in a house with all carbon steel cutlery and the men folk all carried carbon steel pocket and hunting knives. Stainless knives rarely entered the picture and when they did it was always a disappointment. I know there are better stainless steels now, but I like blades that change color with use.

Well they may be better, but it's quite possible that they're still not as good! That's what my testing so far says anyway!

I grew only really with stainless blades, carbon steel was a novelty, and a rare one at that. The only carbon steel blade that I used over an extended period of time was a KaBar, and that was powdercoated... So I definitely never developed the discipline thats required to look after them. Camp knives are fine, but kitchen knives seem to be another matter!

 

[Willie71]

I find a light vinegar or lemon juice etch helps a lot with O1 and surface rust. I lightly oil them between uses as well. Might be interesting to see if a 10 min vinegar or lemon juice etch changes the corrosion problem from your test. Wouldn't take long.

 

[North]

Thanks for sharing the results of your testing! I know that it has been a lot of work. :thumbup:

Bill

 

[aarongough]

Thanks for sharing the results of your testing! I know that it has been a lot of work. :thumbup:

Bill

No worries mate! It's been very useful and informative for me, if it's of some use to other people then that's a free benefit!

 

[Don Nguyen]

I remember encouraging you not to test out so many types of steels and to focus on a smaller group for simplicity's sake, but you've proven me wrong with these tests. Really well done man.

 

[LRB]

Considering that all of the HT work may not be up to the max results, what has he proven?

 

[Don Nguyen]

Considering that all of the HT work may not be up to the max results, what has he proven?

Even if all the HT isn't up to the max, I have a feeling he gained a lot from doing this much already. My point from when he originally asked me for input was that he might have been biting off more than he could chew, but from what he's demonstrated here he didn't.

 

[jawilder]

Great study! Thank you for all your hard work and for bringing us along the journey with you. And welcome to Bladeforums!