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Chip F.





Joined: 05 Jan 2015

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PostPosted: Sat 21 Jan, 2017 5:29 pm    Post subject: Pattern Welded Strength         Reply with quote

Hello everyone,

I an designing a custom longsword to be built by Rob Miller at Castle Keep. I love the look of pattern welded steel, but I'm aware that what we have today is not equal to the Damanscus steel it resembles. I am curious if pattern welded steel sacrifices strength for aestetic. I want to order a functional sword, not just a good looking one.

Thanks,

Chip
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Addison C. de Lisle




Location: South Carolina
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PostPosted: Sat 21 Jan, 2017 7:34 pm    Post subject:         Reply with quote

Hello Chip,
Pattern-welded steel is not a modern imitation of the original damascus or wootz steel. It's a different process that has been used since ancient Rome and involves fusing/forge-welding sheets of alternating steel together to create a "sandwich", which is then forged out, cut in half and restacked, etc to increase the layer count. This billet can then be manipulated by twisting, stock removal, and cutting and re-welding the bar in various ways to produce a pattern. "Damascus" steel is a crucible steel originating in India which was high-quality steel for its time but not superior to modern steel alloys. It also has an interesting pattern in the steel when etched, though to my knowledge this is not a result of manipulation by a smith.

Pattern-welded steel is not appreciably weaker than a monosteel billet under normal use, provided it's made and heat-treated properly. It's a matter of trusting your maker, and as Rob Miller has been in business for quite awhile and has a good reputation I'd guess that you'll receive a product you're happy with. Good luck!

www.addisondelisle.com
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Philip Dyer





Joined: 25 Jul 2013

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PostPosted: Sat 21 Jan, 2017 8:58 pm    Post subject:         Reply with quote

^Isn't pattern welded stell harder to heat treat proper because in traditional pattern welding you dealing several different carbon content and slag content in one blade?
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Lee O'Hagan




Location: Northamptonshire,England
Joined: 30 Sep 2003
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PostPosted: Sun 22 Jan, 2017 8:22 am    Post subject:         Reply with quote

Hi Chip,
If you can afford the extra go for it,
Rob's current billet supplier is one of the best out there currently working, also that route enables him to make the project more affordable than making it by hand, Happy
he's made me pw blades before, excellent work, again starting with steel from a good quality maker,
a lot of the bad press on Damascus steel comes from comparisons with wootz steel, that is a crucible steel, not pattern welded,
dependant on personal preference decent pw or folded or wootz is as good as it gets,
on many swords being made, the only step up from a perfect mono steel sword is going the pw route,
yes a lot is cosmetics, but,,,,,,

Bad pw, well that's a whole other bag of cheese,
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Ken Nelson




Location: central Wisconsin, USA
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PostPosted: Sun 22 Jan, 2017 8:49 am    Post subject:         Reply with quote

A properly made sword from pattern welded material is no better nor worse than one made from a monosteel. An improperly made sword on the other hand....

Pattern welded blades began as a way to refine and improve the steel used for tools and weapons. It bacame an art form of it's own. It is older than crucible wootz, so it is NOT a way to copy the eastern blades.

One of the refinements that came about through lamination and folding was to even out the carbon content. Carbon will diffuse throughout a bar of steel, even through the welds. The idea of hard and soft layers in a blade due to carbon differences is a myth, unless we are dealing with a very low layer count, or welded on edges. I have a paper that shows mathematically, and checked by experimentation that a blade with over 200 layers in a 4.5mm (3/16in) blade will have such thin layers that the carbon content will equalize within the final weld and subsequent forging. The visible differences are more often a result of other alloying elements such as nickel (bright) manganese(dark) and phosphorus (whiter) all of which move so much slower through the steel. (days or even weeks at forging temperatures to move across the layers)

It is possible to get harder and softer layers in a blade, but that is not advisable. A well made pattern welded blade should act like a single piece of steel and break like one. A blade made with alloys that do not heat treat the same, can often be weaker, and can delaminate along a break, or cause a break because of internal stresses. here are a few examples, a 1080/15n20 blade or O1/L6 blade would make good strong swords, as in both cases the temperatures required for austinizing, quench speeds, and tempering heats are similar, with enough overlap for both alloys to work well together. if you were to use say, 1080 and A2, you might tear the blade apart just heat treating it. The A2 requires more heat to austinize, so either the 1080 will have terrible grain growth, or if you use the lower heat, the A2 might not austinize. and then there is the quench, the 1080 requires oil, and the A2 is air hardening. Not a good mix. It might be able to be done, but I would not recommend it.

Sorry if it was a bit long. Best of luck.

"Live and learn, or you don't live long" L. Long
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Jared Smith




Location: Tennessee
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PostPosted: Sun 22 Jan, 2017 9:39 am    Post subject:         Reply with quote

One possible concern over pattern welded material is the welds themselves. If done well and cleanly, the welds are essentially equal to parent materials which have fused together. The more reputable makers will select the materials so that they do not suffer from dissimilar shrinkage during heat treatment. I would not worry about the strength if your source has a good reputation for producing pattern welded projects.

The bigger issue for me is that you will need to maintain it (clean and lightly oiled after handling) to retain the visible contrast of the layers. In case of neglect, you might have to re-etch it. A local blacksmith or knife maker can most likely help you with that.

Absence of evidence is not necessarily evidence of absence!
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Timo Nieminen




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PostPosted: Sun 22 Jan, 2017 1:39 pm    Post subject:         Reply with quote

Jared Smith wrote:
One possible concern over pattern welded material is the welds themselves. If done well and cleanly, the welds are essentially equal to parent materials which have fused together.


... which is why some people warn against cheap pattern-welded swords, due to the possibility of poor welds.

On the other hand, poor welds can be good: they are likely to stop cracks from spreading. Crack meets poor weld, and stops. Crack meets perfect weld and keeps on going. Of course, the poor welds themselves are a weakness, but most of the welds run along the length of the blade, where the impact of flaws is minimal. Poor welds (as long as they're not too poor) strength the sword across the blade, where you need a lot of strength, and weaken it along the blade, where it will still easily be strong enough.

In summary, poor welds don't mean a sword is non-functional, dangerously weak, etc.

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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J.D. Crawford




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PostPosted: Tue 24 Jan, 2017 1:32 pm    Post subject:         Reply with quote

The other issue is historical accuracy. I've never heard of an original pattern-welded European long sword. Correct me if I'm wrong, but so far as I know, pattern welding was long gone in Europe before the earliest longswords, greatswords etc. appeared. So to my eyes, a pattern welded long sword might look nice, but it screams out 'modern affectation'.
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Chip F.





Joined: 05 Jan 2015

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PostPosted: Wed 25 Jan, 2017 7:46 am    Post subject:         Reply with quote

I appreciate the information folks. Of course I should have known not to compare a pattern welded sword with one made of Damascus steel - I realize of course that we're talking about two completely different traditions and methods of swordmaking here.

J.D. - good point about historical accuracy. I am working on a design for a custom longsword, and while I don't mind a small amount of "modern affectation", I would be remiss to commission a sword with too many historical implausibilities.

This is all disregarding the cost, which will likely drive my bank account into open revolt. Perhaps a regular high carbon steel blade is the way to go.
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Bruno Giordan





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PostPosted: Thu 26 Jan, 2017 1:14 am    Post subject:         Reply with quote

Ken Nelson wrote:
A properly made sword from pattern welded material is no better nor worse than one made from a monosteel. An improperly made sword on the other hand....

Pattern welded blades began as a way to refine and improve the steel used for tools and weapons. It bacame an art form of it's own. It is older than crucible wootz, so it is NOT a way to copy the eastern blades.

One of the refinements that came about through lamination and folding was to even out the carbon content. Carbon will diffuse throughout a bar of steel, even through the welds. The idea of hard and soft layers in a blade due to carbon differences is a myth, unless we are dealing with a very low layer count, or welded on edges. I have a paper that shows mathematically, and checked by experimentation that a blade with over 200 layers in a 4.5mm (3/16in) blade will have such thin layers that the carbon content will equalize within the final weld and subsequent forging. The visible differences are more often a result of other alloying elements such as nickel (bright) manganese(dark) and phosphorus (whiter) all of which move so much slower through the steel. (days or even weeks at forging temperatures to move across the layers)

It is possible to get harder and softer layers in a blade, but that is not advisable. A well made pattern welded blade should act like a single piece of steel and break like one. A blade made with alloys that do not heat treat the same, can often be weaker, and can delaminate along a break, or cause a break because of internal stresses. here are a few examples, a 1080/15n20 blade or O1/L6 blade would make good strong swords, as in both cases the temperatures required for austinizing, quench speeds, and tempering heats are similar, with enough overlap for both alloys to work well together. if you were to use say, 1080 and A2, you might tear the blade apart just heat treating it. The A2 requires more heat to austinize, so either the 1080 will have terrible grain growth, or if you use the lower heat, the A2 might not austinize. and then there is the quench, the 1080 requires oil, and the A2 is air hardening. Not a good mix. It might be able to be done, but I would not recommend it.

Sorry if it was a bit long. Best of luck.


Correct. And I have verified it personally when I could still forge blades myself . I was also donated a nice knife that couldn't be heat treated properly because of a bad matching of steels, it was soft and it also had a bend (due probably to imprecise hammering) that could be straightened by hammering cold (yes), while returning to bent state after a while ...

So either you get billets by some very experienced smith that operates in a consolidated way with a very professional heat treating firm (there are some who can advise smiths with sound infoe on materials choice) or you might end up with a pleasantly looking but sub standard product.
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Eric S




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PostPosted: Thu 26 Jan, 2017 12:27 pm    Post subject:         Reply with quote

Addison C. de Lisle wrote:
"Damascus" steel is a crucible steel originating in India which was high-quality steel for its time but not superior to modern steel alloys. It also has an interesting pattern in the steel when etched, though to my knowledge this is not a result of manipulation by a smith.



Addison, you are right about "damascus / wootz steel being completely different than pattern welded steel but there are certain damascus patterns that were actually created by physical manipulation of the steel billet during forging, "Kirk narduban" (prophet's ladder) is one well known example were the damascus billet was filed, chiseled etc before forging in order to create a reproducible pattern.

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Timo Nieminen




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PostPosted: Thu 26 Jan, 2017 1:22 pm    Post subject:         Reply with quote

Philip Dyer wrote:
^Isn't pattern welded stell harder to heat treat proper because in traditional pattern welding you dealing several different carbon content and slag content in one blade?


Ken Nelson wrote:
It is possible to get harder and softer layers in a blade, but that is not advisable. A well made pattern welded blade should act like a single piece of steel and break like one. A blade made with alloys that do not heat treat the same, can often be weaker, and can delaminate along a break, or cause a break because of internal stresses.


This is if we are considering modern best-practice heat treatment. For pre-modern heat treatment, pattern-welding (and simple lamination) can make it easier to heat treat. Welded-edge and sanmei, whether simple lamination or with a decoratively pattern welded body/sides can really benefit from dissimilar steels with dissimilar response to heat treatment.

In particular, if you don't get the tempering right as can happen easily enough if you auto-temper (or don't temper, just quench), low-carbon alloys will leave you with a blade that won't completely break.

An example of a blade that looks like it was saved from complete failure by such a soft body:

More photos and details at http://vikingsword.com/vb/showthread.php?t=18446&page=2

It isn't always good if a blade breaks like one piece of steel. Here is another pattern welded blade with major damage (looks like the result of major bending), where the cracks haven't spread across the whole blade:

More: http://vikingsword.com/vb/showthread.php?t=15971

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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