Your Opinion: The best PM stainless steel you have used.

This thread is for those persons who have used PM stainless steel knives, and over the breadth of their experience have determined what steel they favoured the most. My intention is to draw on the collective knowledge of this group and determine what steels you have used and what steels you liked/did not like to assist in my considerations for steels to stock and invest resources in learning and adjusting the heat treatment for.

Below is a list of steels I have recently employed in chef knife blades;

CPM154CM
RWL34
S35VN
Niolox (NB-1)
AEBL/12C27

I will soon be adding in the following stainless steel;

Super Gold 2 (takefu) this steel also goes by the name "R2"
Damascus Laminate
and San Mai

The reasons why I will be adding this is due to the sharpen-ability, edge retention and maximum sharpness attainable. Additionally due to the soft cladding on the steel, future thinning will be easier than grinding your way through highly abrasive mono steel.

I am making considerations for the steel M390 by Bohler which is essentially CPM20CV but made differently. My main concern with this is the carbide volume which causes issues for edge strength/overall sharpness and stability at low DPS.

Please weigh in and tell me your thoughts, and let the power of this awesome community debate.

Regards,

Chadd

 

I have two in SG2/R2. A 210 Ryusen Blazen and a 250 Mr Itou. Love it. Sharpens easily on my Gesshin diamond plated. And holds it forever.


Got some work done on the Itou at Chefs Armory in Feb and the edge still feels like it has the bite the gave it.

 

jsut as a note aebl is not PM it ir wrought cast steel
i will for sure be keeping an eye on this thread as i always love reading feedback on steel

 

I put it in this grouping purely due to the fine carbide size, distribution and a basic benchmark for the "sharpest" of the stainless steels. It should be interesting.

 

I just started playing with the PMs, just got a ZDP-189 and one in R2. Will post here with impressions. I am a home user now though so not sure how much I am going to get to sharpen them...

 

My Cowry-X folder from Hattori sharpens quite easily and holds a killer edge.

 

It's not a PM steel, but my favourite steel for kitchen knives is AEB-L, provided it's properly heat treated. It doesn't have the best edge retention, but there's no stainless steel I can get sharper. AEB-L is not equivalent to 12C27, by the way, but to 13C26.

 

You are correct yes, AEBL and 13C26 are the comparative two*

My findings are the same as yours, AEB-L gets the sharpest out of the first group of steels I have listed. It holds its edge reasonably well, but when compared to the others in that group it does dull quicker. The finish on the blade in regards to mirror polishing reveals an "orange peel" effect. To that end I prefer an RWL34 blade for mirror polishing, as it is very clean and I have not noticed it on this steel.

What other stainless steels have you used for chef knives @mark76? What would be next on your list of stainless steels?

 

had a maker call me about why he could not get the same type edge with XHP as he had with aebl. after talking to him about it all things from HT to stones what he was missing out on was the just off the ston "bite" in mater skins XHP jsut didnt have it at the levels he was sharpening. the thought is that XHP being power gets sharper but due to having the limited amounts of carbide (jsut like aebl) more even distribution the wrought melt makes for larger carbides and stringers (super minimal differnece but when really pushing things and testing at the max )
edit to add side note i have worked with
154cm cpm154 s30v s35vn XHP 440c 204p cpmM4 cpm10v cpm3v PD1 Bd1 Bdz1

 

CPM 154 CM is the same as RWL34. One is crucible and the other is erasteel. S35VN performance in kitchen knives is disappointing.

I am abandoning AEBL. I won't use it for my pro chef clients' Knives. My heat treater doesn't do a very good job with it. And he does it like Bohler wants it done. I put an AEBL knife in the hands of an even chef for one nights service. It looked like a hack saw blade the next day.

If you want a fabulous steel that will destroy your hands and wrists to grind, CPM M4.

 

You bring up some good points here I want to touch on. I have not worked with XHP but from the basic alloy make up and some very brief reading about the steel it looks comparatively low alloy. I dare say there will be a lot of Cr carbides which is not particularly fantastic at edge retention comparared to W/V/Nb. I read a particular report about some minor need for upkeep with the finish due to surface oxidisation? I'm going to assume this may be more related to secondary hardening though(Does XHP benefit from secondary hardening??).
What do you know about this? I saw you bought in a large amount so I am very interested.
Also this maker, was he mirror polishing the edge via stropping on his XHP?
Due to the 1.60% C in XHP it will more readily form carbides with Cr which is why it cannot get as sharp as AEBL and has corrosion resistance issues. AEBL has .70% C which is (probably saying things you already know here) a hypo-Eutectoid steel. Therefore there is no free C to bond with the Cr which stays as free floating Cr-Cr within the matrix to only act as an Cr oxide former to prevent rust. Basically AEBL is 1070 with stain resistance (in my non metallurgically trained opinion).

My personal findings with AEBL is that it takes a very sharp edge (Easily) greater than other stainless, but looses it quicker. e.g. if AEB-L gets to 100 points of sharpness, but Niolox(For the sake of comparison) gets to 95 points in sharpness, the AEBL will drop quicker in sharpness over time than Niolox. In real world use, this translates to a steel that to keep it performing superior to its comparative peers, the blade needs higher upkeep. Also a Niolox blade with a mirror polished edge at "95" is more than sharp enough to keep any chef satisfied. That test was conducted with Niolox and Aebl at 62HRC.

I am not a metallurgist and I have no misgivings about the infallibility of my knowledge on the subject. If any of the aforementioned required correction please do so, I will not take it in any way other than what it is.

What are your brief thoughts on the steels you used, aside from XHP?

Pennman you are correct that RWL34 and CPM154CM are nearly identical. RWL34 is an ever so slightly cleaner version, and I have noticed this when polishing knives made out of them. So much so I use RWL34 over CPM154Cm when a mirror polished blade is commissioned. The difference is minor, and may be due to the W and small traces of P and S.

I do find it interesting you believe S35VN is dissapointing in chef knives, I have found it performed better than AEBL(62HRC) and CPM154CM(62HRC) at S35VN(60HRC) in regards to a number of tests. I am not an S35VN fan boy, I pick and choose steels for the task, but I would love to know your opinion on why you find it disappointing.

Abandoning AEB-L due to your heat treater failing the steel is a shame. Take Dalmans AEB-L for example. It holds a great edge, gets balls to the wall sharp. He graciously told me the HT regimen his HT profesisonal uses which is exactly the same as the recommended Bohler HT. Just one of those things I guess. I am interested in your comments about the blade looking like a hacksaw blade after use. I assume this is an exaggeration, but if you don't mind elaborating on this that would be awesome. Some insight into the HRC rating on the steel could assist us too?

I have considered M4 as a steel in the past for chef knives, but like you said it is a B**** to grind so I am not so keen. I also hand finish all my knives and if it is as abrasion resistant as the V% content would have me believe, I doubt I'd get a single blade done by the time I die. How does it go in regards to sharpness, shapenability and strength in comparison to say S90V/10V/20CV?



Loving the convo gents, keep it coming!

Regards,
Chadd.

 

I've used quite a few. CPM154 and RWL34 indeed, 12C27, 19C27 (Suisin Inox honyaki - great steel!) and 14Csomething by Sandvik. I wanna try SG2/R2. I've heard it's got great edge retention, but I don't know how it sharpens up.

 

The hacksaw was a bit dramatic, but there were 20+ *visible* edge defects after service along he blade. It cut tomatoes really really well. But so did my $1.79 Rachel Ray serrated vegetable knife. It was Rc 60. And as for stain resistance, my autopsy knives in AEBL needs to be stored oiled or gets rust spots. In my chef knife roll, an AEBL blade stored dry in my dining room at home has rusted. Seriously?!? Edge holding is poor. Sharpen ability is very easy. They get razor sharp and love leather and cardboard stripping. But the constant honing by a chef in a rod during service will eventually lead it to develop a "grandfathers arch" (your grandfather's carbon steel blade from 40 years ago that only touches the cutting board at the tip and heel). It is due to the heat treating most likely and others results can certainly be different. My heat treater does a bad job of it. Therefore I avoid it.

However, CPM 154CM comes out spectacular. Every chef I have made Knuves for from it raves (and I truly mean it, like they are surprised how good the edges are). And I expect more from XHP which will become my main stainless.

S35VN looks good on paper, but real world abrasion resistance is worse than CPM 154. And this is my experience with my own knives as well as others chef knives I own. And some folders. Gets sharp, but rounds over reasonably fast. Likes stones rather than chef steel or ceramic. 154 outperforms it by an order of magnitude.

M4 is insane. I leave it at a 120grit belt finish. Hand finishing is masochistic. Edge holding is beyond belief. I can't comment on it regarding 10v or S90v since I don't use them. However, it does noticibly better than M390 in edge retention. M390/20CV definitely like stones better and go from 100 on the edge to 80-85 and hold that there a looooooong time.

 

My experience with PM stainless has been with SG2 & Cowry-X. Very happy with both of them. The Cowry-X hasn't been sharpened yet, but holds and edge that comes back easily with a light touch on a ceramic rod. LOVE the SG2. I have a few Tanakas and a few Ryusens. They are very easy to sharpen and hold an edge for a very long time. They can chip, but if you give them a regular kiss with a ceramic rod it's not a problem at all unless you abuse them (I think it removes microchips before they can propagate.)

 

Not sure if my limited experience with PM steels would be useful, but Takamura gyuto in R2 holds edge significantly longer compared to blue#2, A2, 52100 and AEB-L. And I don't remember R2 being hard to sharpen… probably a bit harder than AEBL or 52100 but not by much.

However I've quite a few knives in AEB-L and love them. Yes they aren't the best when it comes to edge retention, but they still outperform white#2 and blue#2 knives that I've tried/had. And I've never seen any signs of rust on any of my AEB-L knives.
I also have and use very often a petty from Butch in XHP. It seems to hold edge much longer than my AEB-L knives, but at the same times its ground much thicker and has less acute edge. It seems to take a bit more time during sharpening.

 

Rust spots on hardened AEBL. Sitting overnight in a humid 74 deg F room.

 

What grit is this knife finished ? Looks very coarse belts , maybe 60-120 grit ? I see rust spots on any stainless in my shop mid way grinding while I work on them , but nothing after they are properly finished .

 

I'm trying to remember my stainless lessons but discolouration doesn't mean rust or bad. Also all stainless will rust at some point.

I worked on a floating walkway that jad 316SS handrails that were covered in what we called tea staining. Aka rust spots everywhere. But it was literally sitting in saltwater spray (one of the worst environments thanks to the wetting/drying cycle)

It may have been some acisic residue left on the blade... or just sh*t bad luck that something funky was happening at that spot... or the HT wasn't right and stuffed up the structure.

 

I'm still waiting for a blank Stephen, so you can test one that is properly hardened.

Exactly.