why is 1050, 1060, 1075 etc. shallow hardening?

[30cal_Fun]

Hi Hamurra,

Thanks, from Kaker.com isn't it , I found some other data that suggests this too.

I ordered C105W1 (1.1545) steel from Telma Knive Steels, here is an analysis of the steel I ordered:

C = 1,0 – 1,1 %
Si = 0,1 – 0,3 %
Mn = 0,1 – 0,35%
P = 0,03%
S = 0,03%

It is high in carbon, but very pure with little else, so it should be very good for creating a Hamon in Tanto's.

Louis

[pkrankow]

My understanding is that blades that historically had harmon, Japanese swords and such, were roughly 1050 steel, so 0.50% carbon. I am not sure how having higher carbon will affect harmon formation.

I know that higher carbon steel requires a less quick quench to get full hardening. In discussions regarding quenching effectively, a TTT curve (or graph), or Time Temperature Transition, also called "isothermal transformation curves" (thanks NakedAnvil and MattBower)
to determine the speed of quench to use, air, oil, water, brine, etc.

I am learning here, even though harmon forming is not high on on my list.

Phil

http://www.purgatoryironworks.com/bulletin2/e107_plugins/forum/forum_viewtopic.php?11948

[Hamurra-e]

Louis
Yep as with anything in Steel making contends can vary.
Good Luck and show your results.

Phil
Japanese Swords can have anything between 0.5-0,8 its a question of period of Time and fashion of school and whats available.
But many Westerners like the 0.5 steel wile its easy and forgiving.

[30cal_Fun]

Thanks for the links Phil!
It has some good information about the TTT curve.
They will probably come in handy at some point, I know a bit about quenching media etc., but not much about transition temperatures or TTT curves and such.
I have been studying the whole pearlite, ferrite, cementite, austenite and martensite thing for some time and even the "magical" bainite hype, and I am starting to understand something about it.
I am not a metallurgical scientist however, so any information is very welcome.
You are probably right in assuming that a higher carbon content will change the Hamon, different chemical composition means different crystalline structures forming.

My understanding is that blades that historically had harmon, Japanese swords and such, were roughly 1050 steel, so 0.50% carbon.

Why does everybody make this statement everywhere these days?!? I don't know where this information came from, but it is simply not true and there is no evidence to base this on.

First of all: Phil, please do not take this last line personally, it is not meant for you but for all those that make this statement. I respect you a lot for your knowledge and input and I do not mean to attack you personally. I just see this statement pop up more and more on a lot of forums. I do not mean to say that I am an expert on metallurgy, or an experienced smith, but I know enough of the Japanese sword (making process) to know that this is simply not true.
Please let me try to explain why the whole 1050-Japanese sword thing is not true and my personal vision on this. If you have any remarks or additions, I would love to hear them.

The first thing you have to remember is that the Japanese sword is a laminate of (lets take the most common Kobuse here): Shingane (low-carbon core-steel) and Kawagane (high-carbon coat-steel), so it is never a single piece of steel.
I have one analysis of Tamahagane and the resulting Sunobe-steel (Sunobe-, or sword-blank steel is the resulting steel of the whole forging/folding/purification process and has the properties that make the final sword), here it is: tamahagane.pdf
As you can see, it ranges from 0,37% carbon (probably for Shingane) all the way up to 0,69% carbon (probably for Kawagane).
In "The Craft of the Japanese sword" by Yoshindo Yoshihara, he speaks of using steel with 0,7% carbon and his brother Shoji using steel with 0,6% carbon.

Hamurra put it well in his statement.

Modern day steel like 1050 can not be compared to Sunobe-steel or even Tamahagane. It has very different chemical properties. Japanese sword-steel is very low in manganese and silicium for a start, very different from western steels.
It is like saying L6, O2 and W2 are all the same steels because they are western steels.

The closest western equivalent we have to Sunobe-steel is probable C70W1 (AISI W1 steel with 0,7% carbon) or even better C60W1 if it would exist.

However, It is true that 1050 is a good sword-steel, and that it is a good steel to create a Hamon with, but it does not mean it is "the same" as Sunobe- or Japanese sword steel.


Louis

[pkrankow]

I have not researched much specifically on Japanese swords. I have looked into san mai, where the edge forming steel in in the middle, and not on the outside. I understand Japanese swords are typically in reverse, the edge holding material is wrapped about a softer core, but that is as far as I have been with that style of blade.


Something else of interest I have read a publication regarding brake drums.
http://www.gunite.com/literature/pdf/BDrum_eng.pdf
Look at the picture of martensite spotting. This is on page 3 of the pdf, page #1 of the document.

Phil

[30cal_Fun]

That's interesting.
then again, technically speaking, a breakdrum is a high speed tool that sees a lot of wear and high temperatures. so if it is just surface hardened, then it could wear of.

[pkrankow]

That's interesting.
then again, technically speaking, a breakdrum is a high speed tool that sees a lot of wear and high temperatures. so if it is just surface hardened, then it could wear of.

Brake drums are also cast iron in most cases. The martensite shows up very dark compared to the unaffected metal is what I was getting at. At least in that photograph.
Phil

[30cal_Fun]

Brake drums are also cast iron in most cases.

I didn't know that, I thought that they would be made from suitable steel considering the wear and heat they see.

[thingmaker3]

Why does everybody make this statement everywhere these days?!?

I am speculating: The confusion might be due to average carbon contents. Average of both types of steel in the nihonjin blades is about 0.50%. Most folk think 1050 is 0.50% carbon as well, even though it can be as low as 0.48 or a shigh as 0.55%. I don't know for sure why the confusion exists, but this might be one reason.

1069 might be a better choice for hammon, due to a bit less Mn.

[30cal_Fun]

I am speculating: The confusion might be due to average carbon contents. Average of both types of steel in the nihonjin blades is about 0.50%. Most folk think 1050 is 0.50% carbon as well, even though it can be as low as 0.48 or a shigh as 0.55%. I don't know for sure why the confusion exists, but this might be one reason.

1069 might be a better choice for hammon, due to a bit less Mn.

I think you might very well be correct about the reason why. It certainly explains the choice for 0,50% carbon, I never quite understood that part.
1069: I never saw this steel in particular anywhere, do you know where I can find information about it?

Also, I found a company who can supply me with C80W2 steel, here is an analysis:
C: 0,75% - 0,85%
Si: 0,10% - 0,30%
Mn: 0,10% - 0,40%
P: Max 0,030%
S: Max 0,030%
I think this steel will be perfect for creating a Hamon, and tough enough for a katana, what do you think?

Louis

[thingmaker3]

do you know where I can find information about it?

http://www.postdiluvian.org/~mason/materials/aisi_sae_steel_compositions.html

The C80W2 looks like an exciting steel to experiment with.

[30cal_Fun]

http://www.postdiluvian.org/~mason/materials/aisi_sae_steel_compositions.html

The C80W2 looks like an exciting steel to experiment with.

Interesting, never knew ordinary AISI steel could differ so much in manganese content.

Someone told me that the manganese content he gets in his steel (1075) is usually much lower than mentioned; about 0,3%.
Do you know if it is true that the manganese content is usually much lower than the 0.30%-0.50% or even 0.50%-0.80% that is displayed in typical analysis?

[Silent]

I think you might very well be correct about the reason why. It certainly explains the choice for 0,50% carbon, I never quite understood that part.
1069: I never saw this steel in particular anywhere, do you know where I can find information about it?

Also, I found a company who can supply me with C80W2 steel, here is an analysis:
C: 0,75% - 0,85%
Si: 0,10% - 0,30%
Mn: 0,10% - 0,40%
P: Max 0,030%
S: Max 0,030%
I think this steel will be perfect for creating a Hamon, and tough enough for a katana, what do you think?

Louis

C80w2 is what we Call AISI w1. But you know W1 varies from mill to Mill.
You can Find it in a lot of Places in Europe, Cheap!


About the Hamons:
1050 to 1095 and the W1/W2 series are Shallow Hardening , and you will get Hamons with them, if they are well treated.

AISI 1060, is a Good Baseline for longer Blades and Will make a Good Hamon. 1075 Too, a litle lesh flashy, but more defined though.
W1 Will be better then Any AISI 10XX Series (Even then 1095, because it has More then 0,8% Carbon wich , by logic doenst allow it to fully harden , and makes it a bit messy to Heat Treat when it Come to Long Blades, and you have very litle time when it Comes to Quenching Temps)

I wish you The best Luck. I wouldn't mind some W1 myself

Regards

[Steve Sells]

AISI 1060, is a Good Baseline for longer Blades and Will make a Good Hamon. 1075 Too, a litle lesh flashy, but more defined though.
W1 Will be better then Any AISI 10XX Series (Even then 1095, because it has More then 0,8% Carbon wich , by logic doenst allow it to fully harden , and makes it a bit messy to Heat Treat when it Come to Long Blades, and you have very litle time when it Comes to Quenching Temps)
I wish you The best Luck. I wouldn't mind some W1 myself
Regards

Maybe english isnt your first language. but could you clarify what you meant by the statement of "over .8% carbon wont fully harden?" As I totally disagree.

[Nakedanvil - Grant Sarver]

Maybe english isnt your first language. but could you clarify what you meant by the statement of "over .8% carbon wont fully harden?" As I totally disagree.

Yeah, I'd like to understand that better too.

[basher]

I only just saw this Thread .
I would consider 1095 and w2 to both be shallow hardening , the ones I use have around 0.4% manganese . If oil quenched (in regular speed oil) they will harden a small way up a blade section (a few mm depending on section) . I have some of Don Hansons w2 and it has around 0.2 % manganese . All these steels make good hamon in water , water/ oil or very fast oil .

the other steels you mention I would consider to be deep hardening , however you can get good hamon from them , they just have to be treated right .
I have used the Uk equivalent ,en9 (1050) , en42 (1075) and with enough thermo cycling (which reduces hardenability),heavy clay and the right oil speed you can get lovely hamon , they tend to be less elaborate than the w2 1095 hamon .

People get hamon from O1 and en45 too .

Playing with hamon takes time experimentation and persistence at least if you want predictability .

there are a lot of variables , manganese being just one ..........
Quench medium , quenchant temp , temp of steel , quench interuption, number and type of normalisations , blade section , clay type , clay thickness, clay pattern, color of the moon and which side you are dressing on can all have an effect .
It can be a persuit all of its own .

[Silent]

Maybe english isnt your first language. but could you clarify what you meant by the statement of "over .8% carbon wont fully harden?" As I totally disagree.

Actually my bad there. Yes English is not my first language.
What i meant was 1095 has more Carbon that it's required to fully harden steel(0.8/0.85), that is taking in consideration you are giving it the proper quenching Medium following the Chart to achieve Full Hardness.
So the rest of the Carbon won't go "in solution" , creating britleness , the rest of the carbites work to improve Edge retention.

Yap i concur with this statment, after you start doing blades aiming for hamon there are a lotof variables, just like when you Quench/harden it.

"Quench medium , quenchant temp , temp of steel , quench interuption, number and type of normalisations , blade section , clay type , clay thickness, clay pattern.
It can be a persuit all of its own . "

Regards