Every time I wanted to buy a knife ,curious about the type of steel of the blade.some marked as steel 440,surgical steel,Damascus or even just stainless.I recently came across that famous Kukri(Ghurka) knives are made out of recycled truck steel.Katana made out of two layers of high and low carbon steel.I feel its better to share personal experiences about particular blade material,rather than technical issues.You guys have a lot of experience on this.
A good place to start is the harder the steel the harder it is to sharpen. Then considering the rust resistance. The size of knife for the job. There are many different steels for different uses. I like a steel that holds a good edge but sharpens fairly easy like 1095, D2, A2, VG10, 440c, ATS 34, 154 cm, 154 cpm, CV, etc. I'm not all that fond of the super steel because of the difficulty in sharpening but they all have a place depending on your job at hand.
You must first decide what kind of steel you want in your knife. Stainless, Carbon or Damascus. All three are good and have their following and specialties. I perfer carbon steel but I also have an use some stainless knives. When you pick your type of steel then you can reduce your search to whichever one in that type you perfer. Example: Carbon 1095....Stainless 440c an so on.
Robert has hinted at this. But the problem is that there's no such simple choice as "Stainless, carbon or damascus".
All those three are groups and there are extremely different steels in all those groups. You have took look at the application that the knife is going to be put through. And then you can match a steel that will suit it best. For instance:
You need a big knife that will take a lot of abuse at a low price in a humid area where you don't have a lot of time for upkeep?
440A will be your best friend.
A big knife with good edgeholding but corrosion resistance isn't important?
Something that will just keep it's edge on and on and on? CPM110V or ZDP189
An extremely TOUGH and stainless steel? CPM3V
and so on and so on. There's no "best" steel. Just best for an application. Some steels aren't even steels. For Dive knives for instance Titanium might be a better option than steel. There are many factors that decide wether a steel is a "good" one.
As to the question whether spring steel is a good knife steel.
Spring steel is tough and has pretty decent edge holding IF the heat treatment is correct and the grind is right. It is not however very corrosion resistant.
I have a Khukuri in spring steel and it's a good user steel. You want to take care and dry the blade after use though.
You are so right Alex, there is so much info on so many different knifes steels, we may need for Madhura to be a little more specific on what steels he's asking about. Great info you gave him though, I'd like to hear more from him about his knives and all.
Everything has already more or less been explained but I'll chirp in on some things now that I have my day off.
First of all there is no such thing as "the best" of anything in the cutlery world. One can optimize the spherodized chrystallized formations of carbides in a steel (Martensite, Pearlite, Austenite, Ferrite and Cementite) but even then the style of the blade dictates what uses it has as does the particular balance of crystallized carbide formations.
As martensite is the hardest form of steel that we know of it is also easy to make the craft too brittle and that's why we need to balance it with the other "elements" to reach the desired result of what kind of craft it will be and how it will be used.
Another issue is the common understanding of hard to sharpen means good. No, even with alloy steels, as long as the carbide formations in the steel has been refined through the scientific research that's been done the last 15-20 years then even if we go into HRC 65-66 the steel remains easy to sharpen and edge retention is naturally improved as well.
Generally when talking about HRC values like this we are talking about very particular steels but really any kind of steel can be refined by the same method to produce very noticeable improvements.
A problem that arises is that the craft has to be forged entirely by hand with the exception for a press or power hammer so the price is much higher than a production blade.
One last thing too, I would be very peculiar about who forged a San-mai style Katana as the traditional sword is a single piece of steel only having been differentially tempered through the classic mud application which makes the core or inside of the steel be highly martensitic which of course runs to the edge and surrounding this is Pearlite and Cementite due to the clay making it cool slower, forcing the iron atoms out of their position inside the carbon and forcing it to become Pearlite; a combination of regular iron (this is Ferrite; regular iron which lost it's place inside the carbon atom as the heat opened the carbon up) and Pearlite. There's yet another element present which is Cementite, quite simply a layered form of Ferrite and Pearlite, adding flexibility for the craft.
That's why there's a common misconception that swords are made of two different steels but in reality it's only one piece that had it's spine and surrounding steel reverted from Austenite into the previously mentioned elements to add support and flexibility for the demanding tasks a sword might come up against as the edge would snap in two or fall apart without that support.
However, using a "sandwich" style sword that hasn't been forge welded properly or perhaps even welded by machine - it's hard to tell but accidents can easily happen in these cases and having a 2lbs piece of sharp steel fly across your room like a fastball is quite nasty.
So everyone here on iKC, please see to it that you buy your swords from people you can trust to make a craft that can withstand the impacts and stress a sword has to survive as it cuts through something or even just being swung in the air.
Thanks Halicon, for the technical side of this little discussion. I guess that's why I perfer carbon steel, so little stainless is forged now days.
Apologies for going off-topic but to answer Robert;
It isn't very hard to get hold of a forged alloy steel, handmade production series or completely custom made. The smiths I've mentioned in the past can do pretty much everything except for Kiyohisa-san.
They refrain from using stainless steels though so getting that kind forged for an outdoor knife I don't quite know where to look, perhaps Heiji-san would be able to but it would have to be double bevel and a traditional Japanese machete (Nata) design.
In all honesty however I can't consider it a worthy tradeoff compared to a well-forged alloy outdoor knife of say BS#2 (Blue steel #2). Absolutely not Super Blue either as it's only a mix of #1 and #2 and sits better in the kitchen. The oxide surface from the pine charcoal will be there to prevent any oxidation on surfaces that aren't touched by the stone and some light rust on the sharpening surface has never been much of a bother.
You would need a good stone for such a blade though if you don't have one. Something around 10-13k grit if it has been forged by hand in order to get enough out of the steel as to not waste it's potential.
The price can't compete with hot forged blades made by the help of power tools but most of the smiths focus on delivering at least a lifetime of daily, heavy use per blade however if not even more. One has to learn to sharpen them properly however as they have flat bevels with a rounded edge (on a stone).
thank you very much Herb,Robert,Alex and Halicon for your valuable contributions for the dicussion.I gained a lot.I recently watched a documentory about traditional Katana making.It says that tradititional smiths asses the carbon content of the iron by its color and hand forged for several ,variable days.So that different schools of smiths having different unique"recipes".
Indeed Madhura, there's a lot of interesting information to be gained if one checks into the history of the Katana. Back in the day of the warring states and whatnot there was of course no definitive science around forging or refining iron ore so there were a lot of impurities in the steel of the old swords.
Each smith apprenticed under a master and later went on to create their own school and so on, passing their forging secrets and steel recipes to the next generation. Today that knowledge is called Kantei and it involves the entire history from nearly two millenia old swords albeit they are quite "tired" and not in the best of condition up to todays Gendaito (translated to modern day sword basically), all the schools, smiths, styles and various effects in the steel.
This knowledge was absolutely top-secret and if a rival smith were to say dip his finger in the water to check what temperate the water is for quenching the resulting sentence would be to have his arm lopped off which would put a prompt end to that smith's career. There are many cases of this throughout history with not dismemberment being the worst outcome. Each smith was a huge benefit for the province and the military kept a constant eye for any possible eavesdroppers trying to gain their valuable information of how to forge weapons.
Also ironically, the impurities in the iron lots of old have made it impossible for us to recreate some of the best swords (and many different stunning effects in the steel) known through history as we simply can't find any more of it.
Well I can go on about this for hours but I suppose it's time better spent working as I am yet to find someone else here on ikc interested in sword polishing and Kantei. :)
1095 or 5160 for me.
Oh yea Pat, that's two of my favorites but don't forget about O1 Swedish steel. It's great stuff. Thanks Hal, for your valuable info, we need to know the facts.
Sorry Halicon, I guess there's not too many sword people in here but I was thinking, I started a mini group in the Group Box Full of Knives, call Forged Knives. I was wondering if you would do me and others a favor and do a short explanation about Forgeing a fixed blade knife. I know you are a busy man, so it's alot to ask but there would be no hurry and you don't have to make it too long. Let know what you think.