[Kenneth Armstrong]

I'm aware of the "pattern welding" that was done on Viking and Celtic weaponry, but how was the medieval blade forged? Was it cast, pattern welded, or a combination of both?

[Nathan Robinson]

This might help:


Ground or Pound?
A Comparison of Forging and Stock Removal
An article by by Patrick Kelly

[Arne Focke]

A few rough points:

During the early medieval ages pattern welding was gradually abandoned simply because it was now possible to produce steel suitable for a blade. At the end of the "pattern welding era" very complex blades can be found in which bladesmiths show what they are capable of. At this point pattern welding is mainly used for pomp and not for use anymore.

It is not possible to cast a blade, because the casting process makes the material very brittle.

I hope I could help.


Greetings from Kiel, Germany.

[Geoff Wood]

[Arne Focke]

Of course, bronze blades were cast and then hardened with a hammer.

[Kenneth Armstrong]

Thanks for the replies!

The only reason why I brought up casting was because I've seen TV specials where experimental archaeologists cast bronze weapons, I had no Idea if that was eventually used for steel or not.

I'll read through that article, thanks for the link!

Read the article, now I have a couple of questions.

How is the steel itself created? I assume the swords are created from blocks of steel, but how are the blocks formed?

[Sam Barris]

[Geoff Wood]

[Ben Strickling]

[Geoff Wood]

[Geoff Wood]

[Kjell Magnusson]

[Jesse Frank]

Hi all,

Been a while since I've posted.

Re: caststeel blades.

David Boye started doing that back in the early 80's.

http://www.boyeknivesgallery.com/ Check out the "dendritic steel" section. Pretty neat stuff

Re: grain structure/elongation

You will pretty much always have a grain direction, even with modern crucible steels. I've got a bar of W1 that I forgot in a vinegar etch for a couple months, and it looks just like old wrought iron now. I had that thing a 2300f for quite a while. The exceptions to this are the CPM (particle metallurgy), which are mixed in a powder form and compressed.


RE: how steel was made.

Lot's of different ways to go about that, but they are all basically the same, at least in these periods.
Here is a thread that I posted a while back:
http://www.myArmoury.com/talk/viewtopic.php?t...ight=bloom

I've also got a section on forging the bloom here:
http://jfmetalsmith.com/smelting2.html
I don't know if that helps or not, but I hope it does!

Jesse

[Kjell Magnusson]

[Jesse Frank]

The bar was bought as cold drawn square. It was kept at a welding heat for several minutes and air cooled. I had welded it into a billet to make some knives out of. Others that I have made from the same batch have all shown the same marked grain pattern when polished and etched, regardless of prior/current microstructure. It's one of those things that isn't apparent when you polish it like normal with sandpaper, but when you go at it with a very long, slow etch, or hit it with powdered abrasives with the correct backing will jump right out at you.

[Kjell Magnusson]

In that case, could it perhaps be that what the etch brought out was chemical inhomogeneities, instead of the grain structure itself?

[Jesse Frank]

The alloy banding will follow the grain flow.

Grain flow is just a fact of life when dealing with crucible steels.

[Kjell Magnusson]

Initially the grain size and alloy segregation would go hand in hand, yes, my thought was though that later treatment might produce a new grain structure which didn't follow the alloy banding quite so close? (Though, with the alloy content affecting surface tension and such, I guess some dependance will always be there.) In this case for example, the possibilities I see would be recrystallisation (if the deformation during cold drawing or welding was sufficient), grain growth, and transformation perlite->austenite->perlite (partially, at least) if the temperature is high enough (welding temperature should be over 1000K or so I guess).

The first two processes would tend to "round off" grains (minimising the surface tension, as round shapes gives us the least amount of surface per volume), unless the surface tension varies much with the crystalline directions, in a homogenous material. Not sure to what extent alloy banding would chance that. Also, the phase transformation could, at least potentially, recreate the grain structure entirely. Not sure how the concentration differences will affect this either, but as we no longer have the huge difference in alloy transport rate which was present during solidification, I don't see any need for the new structure to mimic the structure achieved during the original solidification at least (which should be when the alloy banding was initially created iirc).

So, taken together, it would seem to me that there is the possibility of the grain structure diverging (at least in part) from the alloy banding after the original billet has been processed a bit. Looking back to what I initially wondered/suggested, this could indicate that grain flow doesn't necessarily survive phase changes, recrystallisation and such during the forging of a blade, in which case the impact of such factors on the final properties of a blade might be neglible.

Anyway, the chance to compare my scraps of theoretical knowledge here with actual experience with these materials is greatly appreciated, so thanks for mustering the patience to deal with me.

[Geoff Wood]

[Kjell Magnusson]

That cleared it up, yes. Thank you very much for the link.