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Carbon treating sword blades
2

Carbon treating sword blades

Carbon treating sword blades

(OP)
My materials engineering friend and I were having a conversation about carbon treating sword blades.  I had recalled that one of my professors said that in medieval times sword makers would plunge hot sword blades into pigs so that the fat would carbon treat the metal.  My friend didn't think there would be enough time for the carbon to migrate into the metal and that the purpose was to merely rapidly quench the blade.

Anybody else heard this or did I misunderstand my professor during his lecture.  

RE: Carbon treating sword blades

I'd call it a controlled quench, since a live pig would have a standardized body temperature.

The organic quench might offset some of the surface decarburization that would otherwise occur.

Mike Halloran
Pembroke Pines, FL, USA

RE: Carbon treating sword blades

Mike,

Does plunging a glowing sword blank into a live pig seem vaguely barbaric?

Not sure where you are in the world but the History Channel showed an interesting series on some of the skilled craftsmen from history. The swordmaking one is repeated soon:

http://www.thehistorychannel.co.uk/site/tv_guide/full_details/People/programme_2335.php
 

----------------------------------
  Sometimes I only open my mouth to swap feet...

RE: Carbon treating sword blades

I'd have thought a pig was far too valuable to waste.

Although, of course, it can still be eaten, but that is not a great way to kill a pig for eating.

I'd guess it was just an urban legend, although I suppose somebody, some time, would have tried it.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: Carbon treating sword blades

Probably some ill-informed attempt to explain the origins of the term pig iron.  Pig iron is derived from word pygg, which means "clay".

Any credible documentation on the "pig quenching" method out there?

RE: Carbon treating sword blades

Why would a live pig be better than a recently killed dead pig?

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: Carbon treating sword blades

I forgot to mention that "carbon treating" would be redundant, because medieval swords had very high levels of carbon throughout.  Hence my thought that an organic quenching medium might partially offset decarburization.  

What better way to provide a controlled temperature of the quenching medium would be available to a medieval armorer?

Costly consumables are accepted as part of the cost of making first class arms even today.

Of course "pig quenching" sounds barbaric.

So does "pig roasting".  

I ate roast pig at Christmas.  

I'm sure the pig was none too pleased.

Mike Halloran
Pembroke Pines, FL, USA

RE: Carbon treating sword blades

Well, just from a practical perspective, as I keep saying, killing a pig by skewering it with a red hot sword is bad butchering practice, and probably not too great from a Health and Safety perspective (This is Lefty, my pig handler)

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

RE: Carbon treating sword blades

Absolutely true, not good butchering practice.

But the objective of the exercise is quenching the sword, not butchering the pig.  The pig would be discarded as process waste.

I'm sure the peasants would redirect the armorer's waste stream, clean and dress the remainder of the pig, and roast it properly.

And if a Public Health Official jumped out of a time machine and had a problem with that, they'd clean, dress and roast him, too.  No sense in wasting all that protein.


Mike Halloran
Pembroke Pines, FL, USA

RE: Carbon treating sword blades

Why waste a valuable resourse like a pig ? Better to use a politician or lawer.

RE: Carbon treating sword blades


For the sake of pigs, politicians and lawyers for tempering hot swords is better to deep them into quench oil.

Cheers

Luis

RE: Carbon treating sword blades

OH! That kind of pig. I was wondering where medieval armourers would find a pipeline from which to extract the pig.

On the subject of Pig Roasts, can I refer you to MARINE GUIDANCE NOTE MGN 222 (M+F)

Quote:

USE OF BARBEQUES (BBQ's) AND PIG ROASTS ON SHIPS AND FISHING VESSELS

Notice to Ship and Fishing Vessels Owners, Ship and Fishing Vessel Operators, Managers, Seafarers and Fishermen

I assume these to be the aquatic breed of pigs and are the victims of modern fishing methods. I guess they are best cooked and eaten when caught.

JMW
www.ViscoAnalyser.com

RE: Carbon treating sword blades

Hey Teacher! live the pigs alone...

RE: Carbon treating sword blades

   My metallurgy teacher in college claimed they used a nice, fat slave.  Why waste a pig?  

   I saw something on TV about japanese swords being heat treated this way.  

   A lot of historical claims like this can be worked out by looking at the logistics.  Something like ten percent of Japan's population were samauri.  You figure that each one needs more than one sword, that means they expend a lot of slaves, very likely, more than were available.

                         JHG
   

RE: Carbon treating sword blades

drawoh

Your teacher was from the South of US.

wasn´t he?

Cheers

Luis

RE: Carbon treating sword blades

(OP)
This light hearted thread is turning out much more funny than I thought it would be.  

On a side note, barbaric acts in medieval times?!?!  It can't be...!

:D

RE: Carbon treating sword blades

I had heard that they used slaves...

Dik

RE: Carbon treating sword blades

The Gallic’s they had great predilection to eat wild boars. To temper its swords they had for habit to use Romans.

luis

RE: Carbon treating sword blades

I read one acount of a sword maker that use the urine of a small boy for tempering swords.  I forget the exact age but older was not supposed to have amonia in his urine.  Does that make any sense?

RE: Carbon treating sword blades

I prefer a double-bladed battleaxe or a warhammer.

RE: Carbon treating sword blades

Ball war hammers were great and very effective anesthetics when hitting on the heads of the warriors.

Cheers

Luis

RE: Carbon treating sword blades

I would think you would want a relatively homogeneous material for quenching the weapon.  A pig or a person is not exactly that.  Plunging a just formed blade into a person or a pig would likely ruin the work.  However, pig fat might provide a suitable source of oil for quenching a blade.  I do wonder if a comparison has ever been done on what available materials in the medieval world would have provided the best quenching.

Regards,

RE: Carbon treating sword blades

Olive oil would probably come close to the quench oils in use today, although I have no idea how readily it was available in the necessary quantities.

RE: Carbon treating sword blades

Well, at one point Italy suposedly made the finest blades, maybe it was the olive oil?

RE: Carbon treating sword blades


The development of the sword was not possible until ancient civilizations discovered how to mine and work metal. Thus, the first swords were probably made of the oldest worked metal, pure copper. The earliest copper mines were in Egypt around 3700B.C., and in Anatolia (in what is now Turkey) around the same time. By about 1900B.C., copper working had spread across Europe, and presumably copper swords were made during this era. Copper alloyed with tin produces bronze, and this metal made stronger weapons than pure copper. The earliest bronze swords were made by the Egyptians in about 2500B.C. They made blades by heating bronze ingots or by casting molten metal in clay molds. Bronze swords were used throughout the ancient world, until bronze was replaced by iron as the metal used to make weapons. The Hittites knew how to smelt iron as early as 3000B.C., but an efficient method of forming the iron into blades was not discovered until somewhere around 1400 B.C. The Hittites were the first to harden iron for blades by heating it with carbon, hammering it into shape, and then quenching it in water. They kept their methods secret for as long as they could, but gradually ironworking spread across the ancient world. The Romans used iron swords with double blades, a weapon for hand-to-hand fighting. A bigger sword, which could be used to fight from horseback, came into vogue in Western Europe by the third century. Both the Vikings and Saxons were renowned swordsmiths. They used sophisticated ironworking techniques both in forming and decorating their blades.

After Forming,core Drawing out, Fitting the blades, Packing the edge, swords were subjected to tempering, Filing and grinding

Tempering
·    Now the blade is tempered—transformed from soft, workable metal into a hard blade. The smith holds the blade over a fire that may be a long fire built specially to fit swords. The difficulty is in getting an even heat all along the length of the metal. When every part is glowing an even color, the smith quenches the blade in a vat of oil or brine. For this first quenching, the blade is placed in the vat with the blade held flat, parallel to the liquid's surface. After it cools, the smith cleans off the metal scale that collects on the blade's surface. Then, the smith heats the sword again, in a slightly different way. The smith heats a long iron bar to orange-red, and lays the sword on it. When the sword heats to a blue or purple color, the smith lifts it with tongs and quenches it again, this time edge down (perpendicular to the first quenching).

Filing and grinding

·    The blade is next polished with a series of fine files. The edges are ground sharp on a grindstone, a rotating wheel of textured stone.

Decorating

Many blades were elaborately decorated with inlaid patterns. Usually the sword was sent to a jeweler for this step. The jeweler engraved a pattern on the metal, and then often etched it out with acid."

Cheers

luis

RE: Carbon treating sword blades

wow

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