Sandvik Hardening Guide

Hi guys,
I have been on a swedish-style holiday, 6 weeks. Sorry for my lack of posting, but now I'm back. And I am now a member of the prestigeous SSSS group, thanks everyone.

First of all I would like to thank you all for the interest shown in our products. I will try to repay you all with answering your questions.

It's good to be back.
//Jerker
 
Broos said:
Jerker,
Can you explain how you came up with your ratings on edge stability? I have looked into this and asked about this steel characteristic but have not got any detailed information on how it is determined or tested beyond Mr. Landes' descriptions provided here a while back (he described a test that applied a lateral load on the knife edge, but didn't explain how the results are measured or observed). I'd be interested to hear how you have rated this, or any insight you have on it.
Thanks!
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Hi Broos,
Larrin answered you quite good here I think but I'll add a comment or two.

Carbide size and carbide volume are, as Larrin said, very important for edge stability. Large carbides will tend to "come loose" when enough force is placed on them. So large carbide steels will have lower edge-tability than fine carbide steels. But I can't present any nice test results for this, but we do have experience with this phenomena so it's a familiar behaviour for us.

High carbide volume will mean that a crack easily can jump from carbide to carbide with only small areas of steel matrix to slow the propagation of the crack. The steel matrix (matrix = stuff holding the carbides in place) will resist cracks. Imagine a steel with 100% carbides, that would be a ceramic. Wear resistant but too brittle for most applications. No carbides would be a carbon steel (not 100% true but close enough). Tough but with limited wear resistance. With a high carbide volume the steel shows "ceramic" behaviour, like edge-chipping. PM steels will perform closer to ceramics than our fine-grain steels due to their high carbide content. This will then mean that they are more prone to edge-chipping than our steels. I have no way of actually testing this to get nice scientific data, I rely on my theoretic reasoning. And more than a few steel analysis we have made of competing steels.

So far I have pretty much just repeted Larrins words. But there is also another aspect. If an edge does not chip it WILL roll at some point. Resistance to rolling is hardness. So fine-carbide (or no carbide) with high hardness will excel at resistance to edge-rolling.

The combination of resistance against chipping, carbide tear-out and resistance to edge-rolling are the three key points i have used for my grades of the different steel types.

There are others which I have not mentioned that will play a smaller roll. Like carbide shape. Round carbides is better from a toughness perspective than pointy ones. Even carbide distribution is also important, if there is excess carbides in the edge it will easily chip and if there is a deficiency in the edge it will decrease wear resistance for instance.

Puuh, long answer to a short question. To sum up, no we have no scientific way of measuring edge stability. It comes from theory, years of observation and our more or less qualified guesses.

//Jerker
 
thombrogan said:
Hi Jerker!

Would 7C27Mo2 hardened to RC55-57 be noticeably more impact resistant than 12C27 at a similar range of hardness? This would be for a large brush-clearing knife which may occasionally strike rocks.

Many thanks,

Thom
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Hi Thom,
In theory yes, lower carbide fraction (less carbon) will increase toughness. But in reality I think you would have to be hard pressed to notice the difference. I would personally go for 12C27 or 12C27M in that hardness range for the increased wear resistance (unless corrosion is an issue).

FYI: We did an impact test here in our lab comparing the impact strength of D2 at 54 HRC against 12C27 at 58. 12C27 turned out to absorb 3 times more energy than D2 despite the hardness difference. We did this test because D2 is rumoured to be very tough, but that contradicted our theory about martensitic steels here.

The D2 blade was a knife like you describe, although I will not disclose the exact brand or model, so I think 12C27 or 12C27M would suit you nicely.

//Jerker
 
Thanks much, Jerker! Very nice to know that 12C27 can survice both the dishwasher and great outdoors.

And welcome back from your vacation, too!
 
A bit off topic ... but does anyone know where I could find some moderately-priced general kitchen cutlery here in the US with 12C27M (preferred) or 12C27 blades, hopefully hardened to similar levels used by Mora of Sweden for it's general line of working knives? I've spotted a few EKA and Svord kitchen knives on the web, but no real selection and more high end than I had in mind. Food service industry blades with synthetic handles would be great.
 
Not quite what you mentioned, but Bark River sells kitchen knives with 12C27 hardened in the RC58-60 range with micarta and G-10 handles. While softer, Thiers Issard makes some Sabatier knives in 12C27 with micarta as well.
 
Dog of War said:
A bit off topic ... but does anyone know where I could find some moderately-priced general kitchen cutlery here in the US with 12C27M (preferred) or 12C27 blades, hopefully hardened to similar levels used by Mora of Sweden for it's general line of working knives? I've spotted a few EKA and Svord kitchen knives on the web, but no real selection and more high end than I had in mind. Food service industry blades with synthetic handles would be great.
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Hi DoW,
Mora makes kitchen knives in 12C27 and maybe 12C27M. The reason they use both steels is the fact that they used to be two companies "Frost" and "KJ Eriksson". Frost went for 12C27 and KJ for 12C27M. Check this one out:

http://www.moraofsweden.se/index.php?id=308

or the whole PDF:

http://www.moraofsweden.se/get.php?file_id=1808

I'm not sure how available they are to consumers though, maybe most of it ends up in proffessional use like butchers etc. But if you push Ragnar at Ragweed he might be able to get a hold of some of them.

//Jerker
 
thombrogan said:
Thanks much, Jerker! Very nice to know that 12C27 can survice both the dishwasher and great outdoors.

And welcome back from your vacation, too!
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Hi again,
For the dishwasher we recommend 12C27M. 12C27 can take it with a very good heat treat but there is little room for errors. Larrin tells me he can get 13C26/AEB-L dishwasher safe which is good but there would be NO room for errors there.

Overall for the outdoors I personally recommend 12C27, at least until the first of January 2009 ;).

//Jerker
 
Razorsharp244 said:
Hi DoW,
Mora makes kitchen knives in 12C27 and maybe 12C27M. The reason they use both steels is the fact that they used to be two companies "Frost" and "KJ Eriksson". Frost went for 12C27 and KJ for 12C27M. Check this one out:

http://www.moraofsweden.se/index.php?id=308

or the whole PDF:

http://www.moraofsweden.se/get.php?file_id=1808

I'm not sure how available they are to consumers though, maybe most of it ends up in proffessional use like butchers etc. But if you push Ragnar at Ragweed he might be able to get a hold of some of them.

//Jerker
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Thanks, Jerker! I knew I'd seen MoS food service knives before, your suggestion of contacting Ragnar is excellent. I wonder if anyone else here would be interested ... assuming steel performance to be the same as MoS 'Scandi'/'Mora' knives, I would expect these to be terrific performers in the kitchen. I have a nephew who recently married and mentioned they needed some good kitchen cutlery ... and I'd love to have some full-flat grind 12C27 blades myself. :)
 
14C28N, eh?

Thanks for the link to Mora of Sweden. It saddens me that they'd stop at 216mm for their chef knife as I prefer the 255-300mm range for that sort of work.
 
I was hoping that you guys had a tester, but regardless thanks for the reply & explanation, Jerker! :)
 
Pyromancer said:
Doesn't Victorinox use some form of Sandvik steel in their Forschner line?
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IIRC, it's X50CrMoV15 or similar (the stuff also used in Henckels and Wüsthoff). While buttersoft from most every maker using that steel, it holds a nicely polished edge (even if that edge will roll a lot).

Thanks for the link! I see Mora makes a 10.5" and a 12" blade! w007!
 
Ah, the makeup of Vics is X50CrMo @ 55-56 HRC.
I'm currently finding out if the Mora kitchen knives are available in retail stores-otherwise I am going to order from the warehouse.

D
 
Razorsharp244 said:
Overall for the outdoors I personally recommend 12C27, at least until the first of January 2009 ;).
//Jerker
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First you tell us about a 6 week holiday - and don't post any beach bunny pictures. Now you tease us about Jan 2009 and steel.... I'm reporting you to the mods!!! :D
 
thombrogan said:
IIRC, it's X50CrMoV15 or similar (the stuff also used in Henckels and Wüsthoff). While buttersoft from most every maker using that steel, it holds a nicely polished edge (even if that edge will roll a lot).

Thanks for the link! I see Mora makes a 10.5" and a 12" blade! w007!
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Victorinox uses alot of steel and several different grades. They have asked us for something very similar to 7C27Mo2 some time ago, so I know they use that also, not sure what models they put it in though.

Unfortunatly we dont supply them with anything at the moment, we have in the past but most steel for spring parts and such.

//Jerker
 
sodak said:
First you tell us about a 6 week holiday - and don't post any beach bunny pictures. Now you tease us about Jan 2009 and steel.... I'm reporting you to the mods!!! :D
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Hi Sodak,
Well it wasn't anything spectacular. We spent a week in the montains in Sweden doing some hiking, biking and other outdoor activities. And the last four weeks I was working on my house and watching the olympics. It was nice and relaxing though.

For 2009 Kershaw will switch from 13C26 to 14C28N in all their models currently using 13C26.

I consider this grade as an upgrade to 12C27. It hits the hardness of 13C26 (up to 62HRC according to our recommendation) and it has the corrosion resistance of 12C27, at least. It will be a good allround knife steel.

So from a performance standpoint I would put it equal to 13C26 but the extra corrosion resistance will make it more versatile.

//Jerker
 
Dog of War said:
Thanks, Jerker! I knew I'd seen MoS food service knives before, your suggestion of contacting Ragnar is excellent. I wonder if anyone else here would be interested ... assuming steel performance to be the same as MoS 'Scandi'/'Mora' knives, I would expect these to be terrific performers in the kitchen. I have a nephew who recently married and mentioned they needed some good kitchen cutlery ... and I'd love to have some full-flat grind 12C27 blades myself. :)
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No problem,
I dont know Ragnar at all but from hanging around the forums he seems to be the number one importer of Moras to the US so he at least have contact with them. The steel will perform well, Mora is good at heat treating and we have been working with them for a long time. No one knows how long but a good guess is over 100 years.

If you ask the guys at the Survival Forum I think you would get some more guys with you an a larger order for Ragnar. Thoose guys loves the Moras and would probably jump at the opportunity.

I use a couple of their butcher knives they gave me to slice meat with at home and it cuts like a demon. It's not designed to cut carrots, fruits or anything like that but for meat and fish it's really great. It's this type, for butchers who cuts meat all day every day.

http://www.moraofsweden.se/index.php?id=304

//Jerker
 
Broos said:
I was hoping that you guys had a tester, but regardless thanks for the reply & explanation, Jerker! :)
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Hi Broos,
Apart from the good old HRC-tester there is not really alot of good testing machines for knifes or steel that generates a good answer. Impact test for toughness is ok but difficult to translate to any kind of real world values. In fact I kind of like the ABS toughness test where they put the blade in a vice and bends it, but even with such a test the geometry of the blade must be the same for all blades in order to make a fair comparison.

And of course the CATRA, well I'm not really a fan of that one. The one cutting rope is better then the one cutting sandpaper at least but I cant say I like it much. And I'm not sure it even tests wear resistance.

I would like to see more standardized testing but there isn't much out there for knife steel.

//Jerker
 
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