Damascus

Pattern welding steel is known as a perfect welding process, not because it's necessarily strong but because it uses not filler like other techniques. I've never read a complaint about a mono steel blade delaminating.

Doug
 
Unfortunately, the link goes to the front page of the library wanting registration
Interesting, on my laptop computer, the article pops right up, but not on my phone....
If I could pester you a bit more...
Of course. If it's possible to post a pdf, I'll try when I get home. Or i could e-mail it to you if you want to pm me the address.
 
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The article is titled: METALLOGRAPHY OF A MODERN PATTERN-WELDED STEEL KNIFE BLADE
Authored by: Thomas Nizolek
in: ADVANCED MATERIALS & PROCESSES/FEBRUARY 2009, pp 24-25

The article talks mostly about carbon migration.

"For this investigation, a bar of pattern-welded steel was created from W-2 tool steel and ASME AS-203E pressure vessel steel using traditional bladesmithing methods. Samples were removed after each step of manufacture, yielding samples having 4, 8, 16, 32, 64, 128, and 256 layers. Samples were also taken from a heat-treated blade made from the 256 layer material."
 
The article is titled: METALLOGRAPHY OF A MODERN PATTERN-WELDED STEEL KNIFE BLADE
Authored by: Thomas Nizolek
in: ADVANCED MATERIALS & PROCESSES/FEBRUARY 2009, pp 24-25

The article talks mostly about carbon migration.

"For this investigation, a bar of pattern-welded steel was created from W-2 tool steel and ASME AS-203E pressure vessel steel using traditional bladesmithing methods. Samples were removed after each step of manufacture, yielding samples having 4, 8, 16, 32, 64, 128, and 256 layers. Samples were also taken from a heat-treated blade made from the 256 layer material."

Thank you, sir! I found it.
 
The article is titled: METALLOGRAPHY OF A MODERN PATTERN-WELDED STEEL KNIFE BLADE
Authored by: Thomas Nizolek
in: ADVANCED MATERIALS & PROCESSES/FEBRUARY 2009, pp 24-25

The article talks mostly about carbon migration.

"For this investigation, a bar of pattern-welded steel was created from W-2 tool steel and ASME AS-203E pressure vessel steel using traditional bladesmithing methods. Samples were removed after each step of manufacture, yielding samples having 4, 8, 16, 32, 64, 128, and 256 layers. Samples were also taken from a heat-treated blade made from the 256 layer material."
Well, he just lost a few of us when he said that he used a steel with very low carbon that probably hardens differently than the very shallow hardening W2. Thats kind of like saying that you are going to judge a series of red wines and having a bottle of Welch's grape juice in the mix.
 
That article is from 2009. The use of A203E wasn't that uncommon. I made my first steel in 1987 with the Moran composition of O1 and mild steel. God only knows what the carbon was like when I finished that billet.
Things have really progressed as the need for high-hardness steels for knives has grown way past the original idea that "damascus" was for strength as opposed to cutting even in the dozen years I have been away.
Which is why I think a study of modern damascus steel carbon content both post billet and post blade forging would be very interesting.
 
I don't recall where, but I believe I read that carbon migration was significant to the point that it practically equalizes, and in relatively few heats.
 
I don't recall where, but I believe I read that carbon migration was significant to the point that it practically equalizes, and in relatively few heats.

Which means that if we lose too much carbon to oxidation at the surface it quickly migrates and equalizes. Too much of that and we have a lower carbon content blade. I'm curious how low that usually is.
 
I don't recall where, but I believe I read that carbon migration was significant to the point that it practically equalizes, and in relatively few heats.
Which means that if we lose too much carbon to oxidation at the surface it quickly migrates and equalizes. Too much of that and we have a lower carbon content blade. I'm curious how low that usually is.
This is true, they do equalize. Carbon will move throughout the steel. Like water seeking its level, it will move from areas of high to low carbon until they are equal, and also be steadily lost to the forge atmosphere unless it is tightly controlled. The rate that it equalizes is dependent on the difference in carbon between the two, the thickness that it has to travel through, and the temperature. When you are at welding temp, and have many layers, each of those layers is so thin, that the carbon dissolves into it pretty much evenly within a very short timeframe. The difference in colors displayed after etching is attributed to the difference of other elements in the steel, which tend to not migrate easily. Moran’s early work using O1/mild steel probably was at best an average of the carbon content of the two steels. I do recall from a video he had made, that he was putting a piece of O1 into the middle during the last weld so the primary edge steel was O1. I don’t know if he did that with all of them, but that would certainly help create at least a decent edge. Either way, knowledge of pattern welding and metallurgy in general has made some pretty huge advances since then. It looks cool and all, but I’m willing to bet that 99% of people doing it are making cool looking steel that in the end doesn’t perform as well as either of the parent steels.
 
That article is from 2009. The use of A203E wasn't that uncommon. I made my first steel in 1987 with the Moran composition of O1 and mild steel. God only knows what the carbon was like when I finished that billet.
Things have really progressed as the need for high-hardness steels for knives has grown way past the original idea that "damascus" was for strength as opposed to cutting even in the dozen years I have been away.
Which is why I think a study of modern damascus steel carbon content both post billet and post blade forging would be very interesting.
Well, you also had the fairy tale about the "damascus cutting effect" and such. ;) In 2009, pretty much everyone that I talked to who was making the stuff was using a mixture like we use today.Assuming the 3-2 ratio between O-1 and 1018, your BEST hope would be like .67 carbon to start off. Compared that to a low starting point of .80-.81 if you use good 1084/5 and 15N20.
 
Moran started with 1/2" stock, three pieces. That's a lot of time at welding temp to get enough layers. I "cheated" when I went to Zowada's and we made my first billet from 1/4" stock. There couldn't be squat left for carbon in there. And, it's bothered me for many years I have no idea of the carbon left in there when I finished making a billet.

I had just hoped in my years-long absence someone had done a graduate study on the topic or someone of note would create samples and have a cousin or something in a metals lab... :)
If one searches the article cited above, in addition to the regular journal article there's a pic of a poster-board style display. It leaves me guessing it was presented at some scientific conference regarding Materials Science. A grad school project on a budget, he likely lacked funds to get post-production chemistries run and estimated the migration based on the amount and distribution of pearlite instead. Not the best way, but still telling as the carbon keeps creeping toward the edges as it's burnt away during forging.
 
Moran started with 1/2" stock, three pieces. That's a lot of time at welding temp to get enough layers. I "cheated" when I went to Zowada's and we made my first billet from 1/4" stock. There couldn't be squat left for carbon in there. And, it's bothered me for many years I have no idea of the carbon left in there when I finished making a billet.

I had just hoped in my years-long absence someone had done a graduate study on the topic or someone of note would create samples and have a cousin or something in a metals lab... :)
If one searches the article cited above, in addition to the regular journal article there's a pic of a poster-board style display. It leaves me guessing it was presented at some scientific conference regarding Materials Science. A grad school project on a budget, he likely lacked funds to get post-production chemistries run and estimated the migration based on the amount and distribution of pearlite instead. Not the best way, but still telling as the carbon keeps creeping toward the edges as it's burnt away during forging.
Kevin Cashen says that he still uses thick layers, starting with 3 1/2 inch pieces of O1 and 2 of L6. Not sure how he breaks it up when he adds )2 to the mix like I have seen him do lately. I typically would do 8 1/4 inch layers of 1084 and 14 pieces of .072 15N20 doubled up to get 7 .144. layers. I have to buy some 15N20 so I will try to get some .156 this time. Still have enough 1/4" 1084 in that 1.5 x 1/4 x 48 for like 18 more billets plus enough of the old Schrade NOS 1/4 x 1 x 36 for like 40 smaller stacks. LOL
 
Well, you also had the fairy tale about the "damascus cutting effect" and such. ;) In 2009, pretty much everyone that I talked to who was making the stuff was using a mixture like we use today.Assuming the 3-2 ratio between O-1 and 1018, your BEST hope would be like .67 carbon to start off. Compared that to a low starting point of .80-.81 if you use good 1084/5 and 15N20.

My only point was, present day damascus started with Moran's composition and folks were using that back when Zowada taught me in '87. Lotta knives out there with low carbon but I bet Bill's don't lose value because of it. LOL

And I agree, by 2009, even well before, folks had settled in pretty well using 1084 and 15N20. I still have some pounds of each from Kelly sitting downstairs that I saved in case I find a maker with a press or hammer in the area willing to split it so we can make steel.
 
Kevin Cashen says that he still uses thick layers, starting with 3 1/2 inch pieces of O1 and 2 of L6. Not sure how he breaks it up when he adds )2 to the mix like I have seen him do lately. I typically would do 8 1/4 inch layers of 1084 and 14 pieces of .072 15N20 doubled up to get 7 .144. layers. I have to buy some 15N20 so I will try to get some .156 this time. Still have enough 1/4" 1084 in that 1.5 x 1/4 x 48 for like 18 more billets plus enough of the old Schrade NOS 1/4 x 1 x 36 for like 40 smaller stacks. LOL

Yeah, Kevin likes that O-1 and L6 combo and mounts a good argument for it being the ideal pairing.
 
Yeah, Kevin likes that O-1 and L6 combo and mounts a good argument for it being the ideal pairing.
I don't know what adding O2 to his normal mix does beyond giving you better dark color. A lot of guys in Europe use O2 and 15N20 or its German sibling 75Ni8.
 
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