440A - I need an education

Could somebody chime in about what the difference is between 420HC and 440A

S&M use 420HC with good results, and certainly holds better than Rough Rider or Case SS

As for Sandvik 12C27, I have a Brusletto Balder, and it cuts into hardwood forever, so I do not think it is like 440A
 
440A: 0.65/0.75% carbon, 16/18% chromium, 0.75% molybdenum, 1% manganese, 1% silicon
12C27: 0.60% carbon, 13.5% chromium, 0.40% manganese
420HC: 0.46% carbon, 13% chromium, 0.30% vanadium, 0.40% manganese, 0.40% silicon

Carbon: Makes a steel harder.

Chromium: Makes a steel stainless over 13%. Binds with carbon to create carbides, which increase hardness and wear resistance.

Molybdenum: Also forms carbides, which increase wear resistance.

Manganese: Keeps the steel fine-grained, and helps with hardenability.

Silicon: Contributes to strength.

From this you see that 420HC has less carbon than the other two, but both 12C27 and 440A has more chromium.
The increase in chromium means that there is less carbon in the steel, to make it hard, since carbon binds with chromium. Hardness ofcourse, is what keeps an edge sharp.
In short, even if 420HC has less carbon, it can get as hard, if not harder than 440A, and is also able to keep a sharp edge for longer. 12C27 has more carbon, but not as much chromium as 440A, and as such can get even harder. (And keep a sharp edge for longer.)

So, my rating of the three steels:
First place: 12C27,
Second: 420HC,
Third: 440A.

Lastly, i am NOT a metallurgist, nor am i really knowledgeable about steel. This is info i've found online, and compiled. It may not be correct, and you may find that in your view, 440A is better than both 420HC or 12C27. If someone more knowledgeable want to correct me, feel free. :thumbup:
 
In my experience, Sandvik 12C27 can be a wonderful steel. PJ Tomes uses it as his standard stainless for his customs and does a great heat treat -- in practice, I've found it to nearly equal well done ATS34 or 154CM in edge holding while being rather easier and quicker to put a scary sharp edge on -- basically it's a balanced steel that works great for EDC. The key is that it has extremely fine grain (quite unusual for most stainless steels) that allows it to easily take and keep a very fine edge.
 
440a can be hardened to R58 when properly heat treated. I find it holds an edge as well as most 1095. It sharpens like carbon steel, has good rust resistance. I like it very much.

Regards

Robin
 
There was a discussion (I think in the Buck sub-forum) about at least some of the reasons why several mfrs used to use 440C, but then transitioned away from it. I think a significant point that was made, was that 440C is much more abrasion resistant, and tougher to machine than other steels (like 440A, 420HC). And, at least back then, they'd also had lots of complaints that 440C was very hard to sharpen (for the average buyer, anyway), for essentially the same reason. A lot of Buck collectors now favor the 440C blades on the older knives, now that we have a lot more efficient options to sharpen these 'tougher' steels.

I'll see if I can find that thread...
 
neeman said:
Could somebody chime in about what the difference is between 420HC and 440A.

S&M use 420HC with good results, and certainly holds better than Rough Rider or Case SS

As for Sandvik 12C27, I have a Brusletto Balder, and it cuts into hardwood forever, so I do not think it is like 440A
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420HC has less carbon and less chromium than 440A.
420HC can be fine-blanked much more easily than 440A. (It is softer in the annealed state.) This makes it less expensive to mass produce blades.

I have measured the hardness of the 420HC blades of three Buck knives. Each has measured 59HRC.
I have no idea what other companies harden their 420HC to.
All I can say for sure is that Buck 420HC holds an edge significantly longer than Case Tru-Sharp, which is said to be a similar alloy, but not heat treated to as high a hardness.

Phil Gibbs, who now works for AG Russell, but spent years as a designer for Camillus, says that 440A can be taken to equal hardness as Buck 420HC. I have no data to confirm, but I usually make the assumption that Phil knows what he is talking about.

I have not performed side by side testing between 440A and 420HC, so I shan't comment.
 
Buck seems to be interested more in their knives as users, while Case caters primarily to the collector, especially in their Tru-Sharp (420HC) knives. By running their HT to a lower HRc, Case lessens the edge holding, but also increases the corrosion resistance of the steel. I believe this is their main aim in the lower hardness, as well as ease of sharpening. The hardness of the S&M knives, in my experience, is somewhere in between that of Case and Buck.
 
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kitkat52 said:
Go look for the truth.Do not believe everything you read on the net.440A is used in knives worldwide.
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Yes, because it's a cheaper stainless steel that's not too hard on the stamping machinery -- that there are a lot of 440A knives is only a testimony for it being relatively cheap and easy to work - not that it makes a good knife. As a cutting steel it's "adequate" for fairly light, undemanding use -- unless you *like* sharpening your knife a lot, then go for it.

Short version: there are a lot of better knife steels out there for the purpose of actually cutting things -- most of the better stainless knife steels will cost you more. You pays your money and you takes your pick.
 
TLARbb said:
Dennis, this is the post that got me to wondering about this and is in reference to blunt factory edges on Queen D2 blades:

http://www.bladeforums.com/forums/showpost.php?p=8521425&postcount=69

So after using 440C for several years, Queen moved to 440A before moving to the current D2. And it got me to wondering why they moved from 440C to 440A. Kershaw uses 440A on Leeks and probably others. Most of the Chinese built knives are Aus 8 or 8C13MoV or some such or 440A.

After looking at the steel charts and data, it looks like probably material cost was the major factor with a machinability factor probably involved to a lesser extent.

I appreciate everyone's input here, so thanks to all who replied. I knew going in that 440A was a low end steel but did not know what the reasoning would be for a maker to use 440A instead of the better 440C. I've gained some insights to the reasons, but none of them make me feel like rushing out to buy a knife with 440A.

Ed
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No doubt that the price for manufacturing was involved. After all this time and technology advancements it is hard for me to believe that 440C is still a lot more money to manufacture than 440A. I would wonder if there is a marketing angle here where some of these companies will downgrade the steel so that they can provide an "upgraded" version later. It seems that companies will often offer a knife with "so-so" steel and then also in D2, S30V or other. Personally the consumer's way of answering the problem is not to buy the knife with the cheaper steel. Having said that I am yet to meet many people who are as knowledgeable as our constituency.
 
420HC vs 440a A person experience: All I have is anecdotal but I owned a Buck 473 Diamondback with a 420HC blade and a Rough Rider 844 with a 440 Stainless (which I assume to be 440a). Both are fixed blades with the Buck having a 3 1/8 in blade and the RR a 4 1/2 inch blade. I used both to cut up a an old wate rbed that I was throwing out. (Much more difficult that you would think!) I also used both on cardboard, and for splitting rotting wood. The Buck dulled much faster the Rough Rider. In fact the Buck has been sharpened twice and the RR still has a good edge. I've since given the Buck to my son. Both knives were made in China and are decent knives for the money but as far as I'm concerned the RR has the better blade based on my personal experience. (it was also less expensive.)
 
Blues said:
I think the normal range is 55-57. I don't know enough about the metallurgy of 440A to know its characteristics if pushed to 58 or 59. Too brittle? Not tough enough? Prone to chip?

This is something that the folks over in the "maker's forums" would deal with and have a better handle on.
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I hadn't thought about the brittleness of it, thanks for a different viewpoint!
 
ive had rr's and colt slippies tested by a friend of mine who is an aerospace machinist for northrop grummond and he said the blades came back at 57rc. which ino is fine for edc.
 
black mamba said:
Buck seems to be interested more in their knives as users, while Case caters primarily to the collector, especially in their Tru-Sharp (420HC) knives. By running their HT to a lower HRc, Case lessens the edge holding, but also increases the corrosion resistance of the steel. I believe this is their main aim in the lower hardness, as well as ease of sharpening. The hardness of the S&M knives, in my experience, is somewhere in between that of Case and Buck.
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that is the way i understand it. hardening will increase edge retention. but sharpening is harder and corrosion resistion is sacrificed.
 
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