Sandvik 13C26

JD Mandrell

JD Mandrell

Joined
Apr 20, 2001
Messages
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Shouldn't this steel be fairly rust resistant?

I bought my first knife with this steel a little over a week ago, have put it into my EDC rotation and carried it twice, and the blade has already started to develop little reddish brown spots on it, even though it was wiped down with Rem-Oil before being carried.

Normal?
 
I haven't tried 13C26, but I've found that on a few stainless knives, new or after sharpening, I needed to clean with a solvent before wiping with oil to prevent superficial rust. I suspect the fine particles from grinding and sharpening that cling to the surface may be the culprits. Wouldn't hurt to try if you haven't already. Happy New Year. :)Regards, ss.
 
I have noticed this with a few of mine also. Just buff it out with some Fritz or similar polish and oil it up. The minor rust spots should not return, at least they did not for me. Mine were caused by salt that bounced of my plate while the knife was open nearby.
 
Happy New Year!
OK, got that over, although it is still 2007 where I am.
(But the single malt still tastes good.)


I looked at the Sandvik web site. They list the composion of 13C26 as
C______0.68%
Cr______13%

To my knowlege, steel makers actually hold their compositions to ranges rather than single exact percentatages, and the standard practice is to report the average of the range. So I think the composition would be more accurately reported as something more like this:
C_____0.65 - 0.71
Cr_____12.5%-14%

As a comparison, 440A has
C____0.65%-0.75%
Cr____16%-18%

AUS8 has
C____0.7%-0.75%
Cr____13%-14.5%

Even at the median value, 13C26 does not have a whole lot of Chromium. It is just about at the lower limit of the "stainless" range (>13%). (IIRC Chromium content starts having an effect on corrosion resistance at something like 8%. It's not like an On-Off switch that occurs at exactly 13%. Any steel alloy with 13% or more Chromium is considered "corrosion resistant steel", but it is known that the corrosion resistance continues to increase with increasing chromium content. The super corrosion resistant alloys have about 20% IIRC. My references are at work.)

I know that Sandvik is supposed to be super pure, but that only goes so far toward corrosion resistance. It is still low in Cr even if a particular batch contained the midrange composition. And if you got a batch at the lower end of the Cr range, the corrosion resistance would dip more.

I said all that to say that it would not surprise me if 13C26 were somewhat less corrosion resistant than you are used to for a pocket knife.
 
I'd say it's more the finish, both a Vapor (440A or AUS6?) & JYD (13C26) developed minor surface rust, and both had that fine beadblast finish. I like the frosty look of the finish, but it doesn't aid in corrosion resistance.
 
Sandvik has VERY small ranges allowed for their steels; however, this steel is still not in the class of 440A or 420, it's more in the 154CM range for corrosion resistance. That coupled with it being bead blasted....and humid environments might be a problem. The main thing is to keep it dry.
 
I too think it has to do with the finish. But im not sure. My storm 2 in the sandvik was used as an edc in every enviornment, being washed in the sink with other kitchen utensils on a weekly basis at least. I experienced no rust or corrosion of any type. I just hope my JYD II doesn't rust. Ive actually never had a knife rust on me before.
I will find out.....

Matt
 
I would be surprised if it was 440A that rusted on you, Hardheart, finish or not. 440A is pretty bullet-proof when it comes to corrosion resistance.

I think Larrin is correct: a combination of a surface finish that increases surface area and provides the possibility of small surface imperfections at which corrosion can start, coupled with an alloy that is less corrosion resistant and would therefore be more sensitive to surface finish issues.
 
hardheart said:
I'd say it's more the finish, both a Vapor (440A or AUS6?) & JYD (13C26) developed minor surface rust, and both had that fine beadblast finish. I like the frosty look of the finish, but it doesn't aid in corrosion resistance.
Click to expand...

That makes sense. :thumbup:
 
I would have to agree with Straitshot - contamination is the most probable cause. Any time I had that type of problem I just hand polish the blade with 600 grit paper and have removed the problem. Remember that stainless steel needs a proper oxide layer to be rust resistant.
 
Knarfeng has it right on. The Chrome within the steel is barely classified as Stainless. Typically, a steel is considered stainless at over 12.5% Chrome. However, at that level they develop surface rust fairly quick. It also has to do with what the chrome carbides are being used for within the steel Certain mixes end up taking chrome for wear resistance reducing the effective amount used in corrosion resistance. D2 and ATS34 are other examples of this. Borderline Chrome and excellent wear qualities. I like these steels because they are good compromises.

Typically, a knife that is truly Stainless in nature has to have over 14% and closer to 16%. 440A, B and C as well as AUS6,8,10 are all examples of steels with much higher chrome levels and much higher corrosion resistance. I had an ATS34 Gerber completely surface rust on me near the ocean in one day of use. However, there was no pitting at all. an SOS pad removed just about all the visible rust. I have had 440B blades barely develope any discoloration in a weeks use in and around the ocean.

Truth is all stainless knife steels will eventually rust, the better ones just don't pit so easily.

I don't know anything about this steel(13C26), but it sounds like a pretty good simple stainless steel. How does it perform compared to say VG10, BG42, 440C etc.?
 
I've gave it a rub down with oil and 1000 grit paper, and that cleaned it all off. I'll carry it some more and see if that helps.
 
Cobalt said:
I don't know anything about this steel(13C26), but it sounds like a pretty good simple stainless steel. How does it perform compared to say VG10, BG42, 440C etc.?
Click to expand...
Both Thom Brogan and I have been very impressed with it, at least with Kershaw's recent heat treat which runs it in the 58-60 HRC range IIRC, and Larrin has posted very favorable comments about the steel as well. It's real strong suit is exceptional edge stability, which lets it take an extremely fine edge at relatively acute angles, with excellent edge retention on materials that aren't heavily abrasive. It also shows good strength and toughness for a stainless steel ... the way Kershaw runs it, it behaves almost like a quality carbon tool steel, in terms of ease of sharpening/burr formation, and not being brittle when flexed or bent.

IMO 13C26 is a very different kind of stainless than the high carbide fraction steels like VG10, BG42, 440C, and S30V. For whittling, bushcraft and other woodwork, or cutting mostly non-abrasive materials like clean plastics, I prefer 13C26. But again if I were cutting a lot of cardboard or used carpet, I'd choose S30V, BG42 or VG10 because of the higher wear resistance due to higher carbide content. I've been EDCing a JYD2 for the past 8-9 months, and find it nearly ideal for my purposes, which don't involve cutting a lot of abrasive stuff. Again the way it takes and holds a very fine edge is pretty remarkable.
 
My Leek in (Jul 07) 13c26 has been clipped to my front pocket for the last couple months. It hasn't left during a ski trip, shoveling snow, going to a swim meet, normal every day activities, etc.

So let me be the first to say that, when I saw your post, I checked mine out. Nothing, no rust. I dont' know if it's the difference in the JYD & Leek or not.
 
It's the bead blast, not the steel. All of my bead blasted knives did that, then they got the scotchbrite, and problem solved.
 
Cobalt said:
Knarfeng has it right on. The Chrome within the steel is barely classified as Stainless. Typically, a steel is considered stainless at over 12.5% Chrome. However, at that level they develop surface rust fairly quick. It also has to do with what the chrome carbides are being used for within the steel Certain mixes end up taking chrome for wear resistance reducing the effective amount used in corrosion resistance. D2 and ATS34 are other examples of this. Borderline Chrome and excellent wear qualities. I like these steels because they are good compromises.

Typically, a knife that is truly Stainless in nature has to have over 14% and closer to 16%. 440A, B and C as well as AUS6,8,10 are all examples of steels with much higher chrome levels and much higher corrosion resistance. I had an ATS34 Gerber completely surface rust on me near the ocean in one day of use. However, there was no pitting at all. an SOS pad removed just about all the visible rust. I have had 440B blades barely develope any discoloration in a weeks use in and around the ocean.

Truth is all stainless knife steels will eventually rust, the better ones just don't pit so easily.

I don't know anything about this steel(13C26), but it sounds like a pretty good simple stainless steel. How does it perform compared to say VG10, BG42, 440C etc.?
Click to expand...
If you look at the amount of chromium in solution, you'll see that they stainless steels don't vary much after heat treatment. 12% chromium in solution is a whole bunch for most steels. D2 only has around 5-8%, for example. 13C26 typically has 11-12% depending on the heat treatment. 154CM has only 10.5%, but makes up for some of that with a large amount of molybdenum. 440C only has about 12%. 440A and 440B have more. 420 has almost all of its chromium in solution, which is why it is so corrosion resistant even though it has low chromium.
 
Most of my experience has been in stainless handguns, and I know that contamination arises from finishing when carbon steels become embedded in the stainless. The Navy had found when comparing two identical revolvers, one stainless and one blued, that while stainless resisted rust to a much greater degree, that once stainless did begin to rust, it rusted at a much faster rate than the carbon. Of course this was with salt spray and the gun was an early Model 60. Anyway, buying knives with polished blades (or polishing them yourself), will provide optimum protection. And if you work on stainless steel, use stainless steel wool, not regular.

Most knife manufacturers should try to remove any impurities. But who knows?
 
Larrin said:
If you look at the amount of chromium in solution, you'll see that they stainless steels don't vary much after heat treatment. 12% chromium in solution is a whole bunch for most steels. D2 only has around 5-8%, for example. 13C26 typically has 11-12% depending on the heat treatment. 154CM has only 10.5%, but makes up for some of that with a large amount of molybdenum. 440C only has about 12%. 440A and 440B have more. 420 has almost all of its chromium in solution, which is why it is so corrosion resistant even though it has low chromium.
Click to expand...

edited to show my misreading of Larrins post, sorry.

Ok, I did not see the "in solution part"

However, the below still stands true....
. First of all, for a steel to be called stainless it has to have a minimum of 12.5 to 13% Chrome in it, thus your 12% Chrome in 440C is incorrect. I have seen several "Knife" sites list low chrome values for the 440a,b,c and they do so incorrectly. Look in any materials engineering book, and you will see that Cr content is in the 14-18 range for most of the 440 steels. If it was as low as you say it would not be called STAINLESS.

154CM and ATS34 (both are the same, one being Japanese, the other american) have about 13% chrome again being called stainless,

D2 is at about 11-12%, so it is not a stainless but is very close.

Also, the higher carbon contents reduce the beneficial effects of chrome in a steel so it reduces the effective working chrome for corrosion, again common knowledge.
 
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