Manganese on Shallow Hardening (Hamons)

D

Don Nguyen

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Oct 4, 2011
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How much does manganese affect the hardening depth of a steel, depending on its wt%? What else plays a role in how shallow or deep it will harden (I'm assuming every alloying element will play a role, but which ones will have more substantial effects?)?

From NJSteelBaron,

1095
  • C- .990
  • Mn-.420
  • Si- .220
  • P- .0040
  • S- .0010

W2
  • C- .916
  • Mn- .215
  • Si- .296
  • P- .0050
  • S- .0020
  • Cr- .069
  • Ni- .042
  • Mo- .008
  • V- .165
  • W- .005
  • Cu- .047
  • Sn- .0060
  • Al- .006

W2 seems to have many more alloying elements, but 0.215% Manganese compared to 1095's 0.420%. From what I have gotten an impression from, W2 seems to be the more popular choice for differential hardening. Is it mostly the ~0.2% Mn difference, regardless of the alloy content?



As a side note, to compare with Blue Steel
  • C - 1.2
  • Si - 0.2
  • Mn - 0.3
  • Cr - 0.5
  • W - 1.5
  • P < 0.025
  • S < 0.004

And Don Hanson's W2, who many have deemed the stuff for hamons
  • C - .95
  • Mn - .22
  • Si - .23
  • V - .19
  • Cr - .15
  • Mo - .013
  • Ni - .08
  • Cu - .14

This is certainly a lot I'm asking, but I am genuinely curious. Phew, I hope I didn't open pandora's box.
 
Manganese, and any other alloy ingredients like vanadium, chromium, or nickel, will slow the hardening speed, and thus deepen the hardenability. Manganese is added to deepen hardenability. The other alloy ingredients refine grain and make carbides to toughen the steel.

What that means in English, is the lower the alloy ingredients, the more shallow hardening the steel. The perfect hamon attaining steel would be 99% iron and 1% carbon ( but there are technical reasons why that is empirical, not practical)
 
Manganese's effect on hardenability is pretty strong. That and a little Cr is the main reason for the oil quenching speed of O1. Almost all the common alloying elements increase hardenability, thus one of the reasons for the low alloy steels, 5xxx, 41xx, 43xx, 92xx, etc. There are a couple of exceptions under certain conditions, but I'd have to look them up.
 
I don't know much about the metallurgy, but to me, W2 seems to give a darker background in the Ji, which means that activities in the hamon are more easily seen and brought out due to the higher contrast range. The extra elements in W2 will probably also increase activity in the hamon.
 
Manganese is the 'big one' to effect hardenability. Chromium is next.

For hamon activity, less is more.
 
Thanks guys. I notice that the minimum amount of Mn I see is around 0.2%. Is this because Manganese is required to an extent for practical purposes, or just a result of how steel is produced?

I'm really curious as to what the Mn does to the crystal structure during hardening. I'll have to look it up or go ask my professor some time...
 
Mn is pretty much required. It's primary purpose in such small amounts is to help control sulpher, but it also adds hardenability. Don's probably right in that it helps in hardenability more than other elements. I have a chart around here somewhere that shows the relative effectiveness of different elements. With a true plain iron/carbon steel, the hardenability would be very low and would depend solely on the carbon % (in terms of alloying effects). Increasing carbon % increases hardenability. If the sulpher is not controlled, it causes all sorts of issues, even in very small amounts.

In terms of what it does in the crystal structure during hardening, Mn mostly dissolves in the iron and only a small amount is present in the carbides. To my knowledge it does not have it's own carbide, like vanadium, chromium, and other elements do, but it will replace iron in iron carbide to an extent, though not much. It is a potent austenite stabilizer. One of the reasons O1 has so much is to lower the hardening temperature a bit to reduce distortion. Enough Mn and you'll have austentite stable at room temperature. When cooling starts in the quench, Mn slows down the formation of pearlite, and also makes the laminations in pearlite finer which is useful in non-knife use of steel.
 
Another thing you have to look at is that sure most of those percentages listed are great to find a starting point but in all reality lots of times steel will have a range of various elements. Hence why some 1075 will form a great hamon and other 1075 wont. Even with w2, it pretty much all will form a hamon but various degrees of one depending on the amount in it (this is before the user end side of things).

If your looking for hamons in steel I would stick with aldos stuff as it has had a good track record of doing good hamons. Ive tried some from other places with mixed results.
 
me2 said:
Mn is pretty much required. It's primary purpose in such small amounts is to help control sulpher, but it also adds hardenability. Don's probably right in that it helps in hardenability more than other elements. I have a chart around here somewhere that shows the relative effectiveness of different elements. With a true plain iron/carbon steel, the hardenability would be very low and would depend solely on the carbon % (in terms of alloying effects). Increasing carbon % increases hardenability. If the sulpher is not controlled, it causes all sorts of issues, even in very small amounts.

In terms of what it does in the crystal structure during hardening, Mn mostly dissolves in the iron and only a small amount is present in the carbides. To my knowledge it does not have it's own carbide, like vanadium, chromium, and other elements do, but it will replace iron in iron carbide to an extent, though not much. It is a potent austenite stabilizer. One of the reasons O1 has so much is to lower the hardening temperature a bit to reduce distortion. Enough Mn and you'll have austentite stable at room temperature. When cooling starts in the quench, Mn slows down the formation of pearlite, and also makes the laminations in pearlite finer which is useful in non-knife use of steel.
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That is an AWESOME response, thanks so much!

quint said:
If your looking for hamons in steel I would stick with aldos stuff as it has had a good track record of doing good hamons. Ive tried some from other places with mixed results.
Click to expand...

Aldo's W2 is what I'm leaning towards. Compared to getting some White or Blue, it's much more affordable. Thanks.
 
Some of the first W2 I tried years ago was no good for hamon. Then found some good stuff and bought literally Tons of it. Yes there can be a huge difference from one melt to another. I have W2 flat bar stock that wont throw a good hamon. Then have this large round stock that gets forged down, any clay added to a blade will leave a mark. :cool:

Best bet now is Aldo's stuff
 
Don's W2 is killer for hamons. I bought a bit of it from him in 2-5/8" round, and I think I'll cry when I've used it up. Probably go straight to Aldo's W2 on that day.

I'm thinking more and more about trying to produce simple iron/carbon steel. This is a very iron rich county, the river I grew up on has black magnetite sand here and there. It's gonna be a long, hard road I'm sure.
 
Wow. Checked that chart for hardenability based on added elements. Listen to Don. The effect of a little Mn on hardenability is huge. Cr is next, though a relatively unused element is wedged between Cr and Mn. Its so rarely used for that purpose I dont remember what it is.
 
Me2, that's what I keep telling people who ask. ;)

I got that info from Howard Clark years ago, then confirmed it while searching for best/most hamon activity.

I've not found a steel better than the W2 I stumble onto...
 
I like Howards 1086M very well too..Its almost like a eutectoid W2 with about .023 Mn..Good stuff.. Ive seen plenty of beautiful hamons from Aldos W2..laugh if you will but one hamon that sticks out in my mind was a waki forged from a railroad spring clip which is something like 1050..It was amazing to the point that I have never forgotten it..Though Im sure a big part of that was the time the maker took to polish it..
 
IIRC, a popular hamon steel for swords and big blades used to be 1070 with very low Mn ( .25%?). I think Aldo's 1075 is close ( .35%), but has more Mn than the old stuff.
Anyone remember where that stuff was from?
 
Wolf Creek Forge said:
I like Howards 1086M very well too..Its almost like a eutectoid W2 with about .023 Mn..Good stuff.. Ive seen plenty of beautiful hamons from Aldos W2..laugh if you will but one hamon that sticks out in my mind was a waki forged from a railroad spring clip which is something like 1050..It was amazing to the point that I have never forgotten it..Though Im sure a big part of that was the time the maker took to polish it..
Click to expand...

I have a fair bit of Howard's 1086M, very good stuff! But it's not quite as good as this W2.

1050 throws a good hamon because of the lower carbon, but it has to be a water quench. Even with high manganese .50% carbon isn't enough for deep hardening. Add .10% more carbon (1060) and the hamon potential drops, because most 1060 is high Mn. Yes I bought a bunch of 1060 too. ;)
 
Ah, maybe it was 1050 with low Mn that I am remembering. Whichever it was, it made tough swords with great hamons. I believe Walter Sorrells used it for a while.
 
Stacy, Bob Engnath was the first I knew of doin hamon work in modern custom knives. I'm pretty sure he used 1050 which is usually high manganese. But with carbon that low it's still shallow hardening. I looked hard and never found any 1070 with low Mn.
 
I asked Aldo if he would have a melt of 1070 with low Mn done, and he said it wasn't really possible in practicality. Since most new steel is just old steel melted down, with the carbon or other elements adjusted upward as needed, the amount of Mn is fixed from the parent metals in the melt. .035% is about as low as you can get without a virgin melt. Virgin melts are in thousands of tons. I have often thought of asking Niagra what a custom small melt ( 100 pounds) from virgin material. Probably very expensive.
 
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