Info Favorites Register Log in
myArmoury.com Discussion Forums

Forum index Memberlist Usergroups Spotlight Topics Search
Forum Index > Off-topic Talk > Modern equivalent steels for medieval armour plate Reply to topic
This is a standard topic Go to page 1, 2  Next 
Author Message
Kristjan Runarsson





Joined: 07 Nov 2015

Posts: 105

PostPosted: Sun 10 Sep, 2017 8:45 pm    Post subject: Modern equivalent steels for medieval armour plate         Reply with quote

Hi,
I want to build my own coat of plates and I was wondering what the modern equivalent of 13th, 14th and 15th century plate steels would have been.

The only stuff I can easily get in terms of carbon steel is 1, 1,5 and 2 mm mild (aka. low carbon) steel (EN 10130 cold rolled plate).

I experimented with this stuff by heating it red hot so that it lost its magnetic properties. When I quenched it, it does become tougher (due to the low carbon content) but EN 10130 does not by any means become so brittle that it shatters when you drop it like C75 would do (or so I'm told). Is 1,5 mm EN 10130 a good match for the stuff the Visby coats for example might have been made of? ... or did they already have something equivalent to EN C35-C75 high carbon steel plate by the late 13th and 14th centuries?

What grade of steel (modern equivalent) would reasonable quality 15th century armour have been made of? I.e. something:

(a) an average knight
(b) a well equipped foot soldier

... might have worn. Presumably the Knight would have worn high carbon armour but would the foot soldier have had a breastplate, helmet and other plate items of lower carbon steel?

I kind of suspect judging by what I have read about armour evolution that from the time they started making armour containing large plates in the mid 13th century and up to the mid 14th century, plate armour would have been made from something somewhat similar to EN1030. However by the late 14th and 15th centuries they would have had stuff much closer to EN C35-C75 and way more people (as in foot soldiers too) would have been wearing higher carbon steel plate by, say, the Burgundian wars than would have worn high carbon steel armour during, say the latter half of the 14th centrury when it would have been mostly worn by knights. But I'd like to hear an expert opinion.

Hardness conversion chart:
http://www.carbidedepot.com/formulas-hardness.htm

Steel type equivalencies:
http://www.mesteel.com/qualities/equivalentscs.htm


Last edited by Kristjan Runarsson on Mon 11 Sep, 2017 7:35 am; edited 2 times in total
View user's profile Send private message
Philip Dyer





Joined: 25 Jul 2013

Posts: 478

PostPosted: Sun 10 Sep, 2017 9:12 pm    Post subject: Re: Modern equivalent steels for medieval armour plate         Reply with quote

Kristjan Runarsson wrote:
Hi,
I want to build my own coat of plates and I was wondering what the modern equivalent of 13th, 14th and 15th century plate steels would have been.

The only stuff I can easily get in terms of carbon steel is 1, 1,5 and 2 mm mild (aka. low carbon) steel (EN 10130 cold rolled plate).

I experimented with this stuff by heating it red hot so that it lost its magnetic properties. When I quenched it, it does become tougher (due to the low carbon content) but EN 10130 does not by any means become so brittle that it shatters when you drop it like C75 would do (or so I'm told). Is 1,5 mm EN 10130 a good match for the stuff the Visby coats for example might have been made of? ... or did they already have something equivalent to EN C35-C75 high carbon steel plate by the late 13th and 14th centuries?

What grade of steel (modern equivalent) would reasonable quality 15th century armour have been made of? I.e. something:

(a) an average knight
(b) a well equipped foot soldier

... might have worn. Presumably the Knight would have worn high carbon armour but would the foot soldier have had a breastplate, helmet and other plate items of lower carbon steel?

I kind of suspect judging by what I have read about armour evolution that from the time they started making armour containing large plates in the mid 13th century and up to the mid 14th century, plate armour would have been made from something somewhat similar to EN1030. However by the late 14th and 15th centuries they would have had stuff much closer to EN C35-C75 and way more people (as in foot soldiers too) would have been wearing higher carbon steel plate by, say, the Burgundian wars than would have worn high carbon steel armour during, say the latter half of the 14th centrury when it would have been mostly worn by knights. But I'd like to hear an expert opinion.
Honestly, I'm no metallurgist but I wouldn't be surprised if the visby pieces were made of iron, people often forget that the people massacred at Visby were very poor peasants wearing armor considered crude and dated by period standards.
View user's profile Send private message
Kristjan Runarsson





Joined: 07 Nov 2015

Posts: 105

PostPosted: Mon 11 Sep, 2017 7:30 am    Post subject: Re: Modern equivalent steels for medieval armour plate         Reply with quote

Philip Dyer wrote:
Honestly, I'm no metallurgist but I wouldn't be surprised if the visby pieces were made of iron, people often forget that the people massacred at Visby were very poor peasants wearing armor considered crude and dated by period standards.


I might be mistaken here, but as peasants went during the Middle Ages, Gotlandic peasants were pretty well off since Gotland was generally a very rich place. As regards the material of the armours I thought the same thing you did but then I took a look at some of the ones with large highly curved plates and started wondering. Take this one for example:



If the original had been made of iron I would have expected these plates to be crumpled up after being buried in the ground with all that earth on top of the (Unless they were bent back into shape by a restorer which given the level of corrosion seems unlikely). I get told a lot that heat treating mild steel will do nothing which is not quite true, there is a noticeable reduction in the softness of the material and it bends less easily but it still bends and I would expect even plates like that to be constantly bending out of shape, but I suppose I'll be finding out soon enough since I'm going to use mild steel for my Visby armour. Maybe if I make the thing out of 2mm plates and harden them they'll be stiff enough that I won't have to bend the plates back into shape every time I take the brigantine off.

P.S. Why is it off topic to discuss what material Medieval arms and armour were made of for the purpose of creating accurate reproductions?
View user's profile Send private message
Kristjan Runarsson





Joined: 07 Nov 2015

Posts: 105

PostPosted: Tue 12 Sep, 2017 3:29 am    Post subject:         Reply with quote

Well, to answer my own question in case it will help anybody in the future I found this thread with data that suggests that before the 15th century hardening or heat treatment was pretty un-common:

http://myArmoury.com/talk/viewtopic.20681.html

Mind you that is too small a small data set to draw sweeping conclusions from but the existence of what are basically air cooled Iron helmets in the 14th century indicates that most re-enactment gear today is of vastly better quality than the 'munitions grade' helmets/breastplates/limb armour of most of the Middle Ages as well as some of the higher grade Medieval stuff and this may have remained the case up to a point into the Renaissance.

Nota Bene, I'm no steel expert and I might be wrong about details so take the below with a certain amount of salt.

As for the steels it should be kept in mind that modern steels are much purer than medieval ones, specially pre-15th century steels, since it was only in the 15th century that large scale production of relatively pure steel started to take off in Europe. Early Medieval steel in particular was full of slag and other impurities which means that modern EN 10025 is probably significantly stronger than Medieval 0,2% carbon steel would have been due to it begin full of slag inclusions. Thus the below mappings are very approximate at best. You wont get a 0.2% carbon steel breast plate for your longbow armour penetration that is a real analogue for what would have been in use at Crecy in 1346 unless you make the steel from ore in a bloomery furnace and then work it and pound it into shape and harden it according to Medieval methods, slag inclusions and all. Furthermore don't forget to make your bodkins of at least 0.2% C steel and harden them, that's one thing (of many) that most of these longbow vs. armour tests get wrong.

  • EN 10130 is a low carbon steel with no more than 0.05% carbon in it so, it's basically iron as far as I can tell. This is an analog for the low carbon armour that you would find on the heads and chests of most Viking age warriors in the form of helmets and (possibly) lamellar armour as well as in poor 'munitions grade' breastplates and limb armour into the 14-15th century. Helmets made of, say 1-1,5 mm plates, which were in turn made of a slag a ridden version of this stuff would explain accounts in the Sagas of people occasionally stabbing spears, slashing swords, and shooting arrows through other peoples helmets. It also puts illustrations in medieval manuscripts of axes shearing through helmets in a new light, not to mention that story of William Marshall getting brained over the head so often his head got stuck in his helmet.

  • EN 10025 is a higher carbon mild steel with a carbon content of 0.18-0,24% carbon depending on the grade. This corresponds to the stuff used for better quality armour (starting in the 12th-13th centuries?) and it could be hardened up to a certain degree although that was apparently not done very often (statement subject to revision due to limited data set).

  • EN C35-C75 Are high carbon non alloy steels. The number after the C gives the median carbon content with C35, for example, meaning that the steel contains 0.35% carbon on average. The C50 to C75 steels in this range correspond to the really high quality properly heat treated Milanese and Augsburg armour you start to see in the late 14th and in the 15th centuries (statement subject to revision due to limited data set).
View user's profile Send private message
Philip Dyer





Joined: 25 Jul 2013

Posts: 478

PostPosted: Tue 12 Sep, 2017 12:18 pm    Post subject:         Reply with quote

Kristjan Runarsson wrote:
Well, to answer my own question in case it will help anybody in the future I found this thread with data that suggests that before the 15th century hardening or heat treatment was pretty un-common:

http://myArmoury.com/talk/viewtopic.20681.html

Mind you that is too small a small data set to draw sweeping conclusions from but the existence of what are basically air cooled Iron helmets in the 14th century indicates that most re-enactment gear today is of vastly better quality than the 'munitions grade' helmets/breastplates/limb armour of most of the Middle Ages as well as some of the higher grade Medieval stuff and this may have remained the case up to a point into the Renaissance.

Nota Bene, I'm no steel expert and I might be wrong about details so take the below with a certain amount of salt.

As for the steels it should be kept in mind that modern steels are much purer than medieval ones, specially pre-15th century steels, since it was only in the 15th century that large scale production of relatively pure steel started to take off in Europe. Early Medieval steel in particular was full of slag and other impurities which means that modern EN 10025 is probably significantly stronger than Medieval 0,2% carbon steel would have been due to it begin full of slag inclusions. Thus the below mappings are very approximate at best. You wont get a 0.2% carbon steel breast plate for your longbow armour penetration that is a real analogue for what would have been in use at Crecy in 1346 unless you make the steel from ore in a bloomery furnace and then work it and pound it into shape and harden it according to Medieval methods, slag inclusions and all. Furthermore don't forget to make your bodkins of at least 0.2% C steel and harden them, that's one thing (of many) that most of these longbow vs. armour tests get wrong.

  • EN 10130 is a low carbon steel with no more than 0.05% carbon in it so, it's basically iron as far as I can tell. This is an analog for the low carbon armour that you would find on the heads and chests of most Viking age warriors in the form of helmets and (possibly) lamellar armour as well as in poor 'munitions grade' breastplates and limb armour into the 14-15th century. Helmets made of, say 1-1,5 mm plates, which were in turn made of a slag a ridden version of this stuff would explain accounts in the Sagas of people occasionally stabbing spears, slashing swords, and shooting arrows through other peoples helmets. It also puts illustrations in medieval manuscripts of axes shearing through helmets in a new light, not to mention that story of William Marshall getting brained over the head so often his head got stuck in his helmet.

  • EN 10025 is a higher carbon mild steel with a carbon content of 0.18-0,24% carbon depending on the grade. This corresponds to the stuff used for better quality armour (starting in the 12th-13th centuries?) and it could be hardened up to a certain degree although that was apparently not done very often (statement subject to revision due to limited data set).

  • EN C35-C75 Are high carbon non alloy steels. The number after the C gives the median carbon content with C35, for example, meaning that the steel contains 0.35% carbon on average. The C50 to C75 steels in this range correspond to the really high quality properly heat treated Milanese and Augsburg armour you start to see in the late 14th and in the 15th centuries (statement subject to revision due to limited data set).

It doesn't shed any new light. Allot of helmets were with space between the helmet and the skull, you wouldn't be able to shear through a crappy with a sword or a axe. People have tested this with swords and axes made of much better steel and helmets allot thinner than originals and the best you can do is clobbering the hell out of someone with a sword or axe through their helmet. https://www.youtube.com/watch?v=Z1KJAeJj3Pc https://www.youtube.com/watch?v=VOSmJbzUgCA Armorsmiths knew they had crap in their and worked hard to compensate for that.
View user's profile Send private message
Timo Nieminen




Location: Brisbane, Australia
Joined: 08 May 2009
Likes: 1 page
Reading list: 1 book

Posts: 1,478

PostPosted: Tue 12 Sep, 2017 4:10 pm    Post subject: Re: Modern equivalent steels for medieval armour plate         Reply with quote

Kristjan Runarsson wrote:
and it bends less easily but it still bends and I would expect even plates like that to be constantly bending out of shape, but I suppose I'll be finding out soon enough since I'm going to use mild steel for my Visby armour. Maybe if I make the thing out of 2mm plates and harden them they'll be stiff enough that I won't have to bend the plates back into shape every time I take the brigantine off.


What are you planning to use the armour for? Unhardened 2mm mild steel should be more than thick enough. When I was fighting in the SCA with 1.6mm mild steel armour, only once was there any damage to the armour (a bent-in fan on a knee cop). 1.5mm should be sufficient for that kind of thing (maybe HMB/BotN is harder on armour and you want to be a little thicker), for a Visby-style coat of plates. But if you want 2mm thick, to have arrow-proof armour, that'll work too.

Plates for brigandine can be thinner. 1.2mm dents/bends rather more easily, but note that HMB/BothN people will use that kind of thickness for brigandine. Original brigandines could be thinner than that - arrows/spears will need to get through multiple thicknesses, and 1mm brigandine will work well.

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
View user's profile Send private message Visit poster's website
Mike O'Hara




Location: New Zealand
Joined: 10 Jul 2010
Likes: 1 page

Posts: 106

PostPosted: Wed 13 Sep, 2017 3:17 pm    Post subject: Mild steel for coat of plates         Reply with quote

Hi Kristjan

I've made several coats of plates on the Wisby design from 1.6mm mild and they serve very well as protective armour, just as Timo says.

What actually matters are the curves you put on the plates. Even the relatively large plates are much stiffer once you have hammered them to shape. Perhaps a litlle of this is work hardening but most is just the shape itself. You can back-curve the edges to make them stiffer again and I also have found this helps the plates 'move' over one another in the armour.

Once you rivet the plates to leather with the proper overlap and fit, the whole armour re-inforces itself and becomes much stiffer. It is not plate armour but is resistant to blows and damage. We tested it by hitting me with a blunt pollaxe. Definitely felt it but the plates didn't deform.

I made one set of 2mm plates and found it heavier than I really wanted and didn't give me than much extra protection.

cheers
mike

MIke O'Hara
Location: Plimmerton, New Zealand
View user's profile Send private message
Mark Moore




Location: East backwoods-assed Texas
Joined: 01 Oct 2003
Likes: 6 pages
Reading list: 1 book

Posts: 2,044

PostPosted: Wed 13 Sep, 2017 3:49 pm    Post subject:         Reply with quote

Weird as this may sound, you can pick up used steel road signs from your local DoT equipment yard. They are at least 12ga....maybe even thicker. And...if you play your cards right, they're FREE. A large one ought to be enough for a CoP. Happy ....McM
''Life is like a box of chocolates...'' --- F. Gump
View user's profile Send private message
M. Eversberg II




Location: California, Maryland, USA
Joined: 07 Sep 2006
Reading list: 3 books

Spotlight topics: 1
Posts: 1,433

PostPosted: Fri 15 Sep, 2017 11:57 am    Post subject:         Reply with quote

They are aluminum, however.

M.

This space for rent or lease.
View user's profile Send private message AIM Address Yahoo Messenger MSN Messenger ICQ Number
Eirik R. F.




Location: Norway
Joined: 08 Nov 2015

Posts: 15

PostPosted: Thu 12 Oct, 2017 10:28 pm    Post subject:         Reply with quote

You have to keep in mind that even plain modern carbon steel have manganese as an alloy, and this will change the property of the steel. It will remove excess dissolved oxygen, sulfur and phosphorus. Small amounts will prevent the formation of liquid iron sulfide. This is turn will prevent impurities in the steel and the tensile strength will increase accordingly.

If you take a look at Italian armour with or without a makers mark from 1360 to 1450 in The Knight and the Blast Furnace, the distribution turns out like this.

15 fully hardened medium carbon steel specimen (approximately a vickers plate hardness of 340 - 400)
3 attempted hardened medium carbon steel specimen (approximately a vickers plate hardness of 280 - 340)
11 air-cooled medium carbon steel specimen (approximately a vickers plate hardness of 240 - 260)
7 fully hardened low-carbon steel specimen (approximately a vickers plate hardness of 200 - 280)
10 attempted hardened low-carbon steel specimen (approximately a vickers plate hardness of 200 - 240)
9 air-cooled low-carbon steel specimen (approximately a vickers plate hardness of 180 - 200)
4 wrought iron specimen (approximately a vickers plate hardness of 160 or less)

(The vickers plate hardness varies with carbon content and slack-quenching.)

As you can see, 23 out of 59 pieces of armour, or about 40 % are made of poor quality, and this is the best armour available during the time period.

If you on the other hand take a look at German made armour from the same time period they are all made of iron or low carbon steel. There are two high carbon steel bascinets in this category, but Williams suspect they are of Italian origin.

Modern steel with more than 0.6 % carbon is too high.

According to the tests Wiliiams carried out, air-cooled modern mild steel with 0.15 % carbon and a fracture toughness of 235 kJ/m2, is close to the lower end of medieval air-cooled steel with 0.6 % carbon (240-260 kJ/m2), whereas modern air-cooled steel with 0.6 % carbon will give you a fracture toughness of 320 kJ/m2. This has to do with less slag and the properties of the steel i.e manganese.

Something like modern plain carbon steel with 0.2%C to 0.3%C would be the equivalent of air-cooled medieval high carbon steel.

The best quality armour with a vickers plate hardness of 400 would require fully quenched 0.35%C to 0.6%C. Probably on the lower end of the scale due to impurities in medieval steel.

If you are going to slack-quench the armour, modern steel behave in a completely different way to medieval steel, as tested by Williams. The time you wait before quenching turned out to be different. The window of waiting is wider without severe reduction in results when dealing with modern steel.
View user's profile Send private message
Mark Moore




Location: East backwoods-assed Texas
Joined: 01 Oct 2003
Likes: 6 pages
Reading list: 1 book

Posts: 2,044

PostPosted: Fri 13 Oct, 2017 3:26 am    Post subject:         Reply with quote

M. Eversberg II wrote:
They are aluminum, however.

M.



I've gotten a couple of used road signs that were steel. They were older signs though. Aluminum may be the new standard now. Happy ....McM

''Life is like a box of chocolates...'' --- F. Gump
View user's profile Send private message
Jean Henri Chandler




Location: New Orleans
Joined: 20 Nov 2006

Spotlight topics: 1
Posts: 1,042

PostPosted: Fri 13 Oct, 2017 8:29 am    Post subject:         Reply with quote

Eirik R. F. wrote:


As you can see, 23 out of 59 pieces of armour, or about 40 % are made of poor quality, and this is the best armour available during the time period.

If you on the other hand take a look at German made armour from the same time period they are all made of iron or low carbon steel. There are two high carbon steel bascinets in this category, but Williams suspect they are of Italian origin.

Modern steel with more than 0.6 % carbon is too high.



Really? I'm surprised by this, it has been a while since I read Alan Williams but I thought by the early 15th Century Augsburg and some of the other German armor making centers was producing medium carbon tempered (heat treated) steel armor and had begun to take over that particular niche from Milan / Brescia. I thought most of the 15th Century South-German armor was of this quality.

I guess I'll have to go back and review the Knight and the Blast Furnace, I have the PDF somewhere.

Generally speaking, I think we tend to understimate the qualities of medieval metalurgy as being tailored for their particular uses. Modern steel is intended to make washing machines, rebar, i-beams and so on, medieval is mostly for armor, weapons, gears and tools.

J

System D'Armes Historical European fencing in New Orleans

Essays on Hroarr

Introducing the Codex Guide to the Medieval Baltic
View user's profile Send private message
Eirik R. F.




Location: Norway
Joined: 08 Nov 2015

Posts: 15

PostPosted: Fri 13 Oct, 2017 9:24 am    Post subject:         Reply with quote

By 1480 armour from Innsbruck, Augsburg and Landshut had surpassed Milan and Brescia.

Go to page 331 and 332. German armour up to 1450.
12 are made from iron, 7 of low carbon steel and 3 of medium carbon steel (Correction, I said 2 in my previous post). These 2 helmets made of high carbon steel might be of Italian origin, and there is no definite evidence as to their origins. They do not have a maker's mark (the part is missing on one of them)

From the samples we have, the majority of armour in use by men-at-arms was of low quality. But then, most of the men-at-arms were not form the rich upper nobility or knights. Most of them were gentlemen and esquires. Clifford Rogers made the numbers to be 13 % with Milanese high carbon steel armour, 33 % with low carbon steel armour and 54 % with wrought iron armour during the battle of Agincourt. The trend is most likely correct and might vary. A general rule is probably 20-30-50, and changing the closer we get to end of the 15th century.
View user's profile Send private message
Jean Henri Chandler




Location: New Orleans
Joined: 20 Nov 2006

Spotlight topics: 1
Posts: 1,042

PostPosted: Fri 13 Oct, 2017 11:18 am    Post subject:         Reply with quote

Eirik R. F. wrote:
By 1480 armour from Innsbruck, Augsburg and Landshut had surpassed Milan and Brescia.


This doesn't quite jibe precisely with my understanding. From what I had gathered Augsburg was way ahead of Innsbruck in armor development, I'm not sure about Landshut but didn't the Innsbruck armor making industry basically get started (or greatly accelerated) by the arrival of Augsburg craftsmen who were being hired by the Emperor ?

For example the famous Augsburg armorer Lorenz Helmschmied and his brother Jörg were making medium carbon steel, tempered armor as early as the 1430's. He seems to have been making armor for Frederick III in the 1470's and went on Maximillian's payroll ~1480 and not long after that he was leading the exodus of Augsburg craftsmen to the Imperial courts.

https://en.wikipedia.org/wiki/Lorenz_Helmschmied

Also, I seem to remember that Milan was already shifting to parade armor, steel but usually air-cooled, by the early 1400's as Augsburg began to gain control of the armor-for-warfare market. Parade armor was more lucrative in general anyway.

Which brings me to the point about cost, but I'll get to that in a second...

Quote:

Go to page 331 and 332. German armour up to 1450.
12 are made from iron, 7 of low carbon steel and 3 of medium carbon steel (Correction, I said 2 in my previous post). These 2 helmets made of high carbon steel might be of Italian origin, and there is no definite evidence as to their origins. They do not have a maker's mark (the part is missing on one of them)

From the samples we have, the majority of armour in use by men-at-arms was of low quality. But then, most of the men-at-arms were not form the rich upper nobility or knights. Most of them were gentlemen and esquires. Clifford Rogers made the numbers to be 13 % with Milanese high carbon steel armour, 33 % with low carbon steel armour and 54 % with wrought iron armour during the battle of Agincourt. The trend is most likely correct and might vary. A general rule is probably 20-30-50, and changing the closer we get to end of the 15th century.


I think it would be risky to generalize assumptions from French, Breton, and English men at arms at Agincourt with the rest of Europe in the 15th Century. People tend to forget that England and France were a bit of a backwater in this period, technologically speaking. To point they imported most of their higher quality armor from Italy or Germany. The epicenters of metallurgical crafts would be Italy, Flanders, South Germany, Catalonia and various other zones in Central, Southern and Northern Europe.

If you wanted good armor, or steel crossbow prods, gun-barrels, or steel gears or tools, you would get them mainly from a handful of cities in these places. Augsburg, Milan, Brescia, Ghent, Barcelona, Nuremberg.

In the same era, England would be the place to buy raw wool, and France the place to get wine, salt or grain.

Nor would I assume that only Dukes and Counts are wearing good quality or even tempered steel harness. The 15th Century was the peak of armor use in Europe, I would say the world, and commoners seemed to be able to afford it.

I can tell you for a fact harnesses "of proof" show up quite routinely in records of guild armouries in "German" towns from Swabia to Livonia, including specifically Augsburg, and also in the annual inspections they did of citizens militia kit. It's hard to generalize about costs and prices in medieval Europe but the cost of these harness at least seemed to be well within reach of an ordinary mercenary lancer, or even a halbedier or gunner, though this varied quite a bit. For example if you base it on records from the Hungarian Black Army as a pretty accessible example - good armor seemed to be well within reach of their pay (when they were paid) not counting loot seized in victory.

From what I have read, even Swedish peasants had pretty good armor in the 15th Century for example at the Dalarna Rising of 1434, the local miners appear to have had Augsburg and Milanese harness which had been captured during previous clashes with Danish mercenaries (or international mercenaries in the employ of the Danes)

https://en.wikipedia.org/wiki/Engelbrekt_Engelbrektsson

The really expensive armor (and therefore the most profitable) seemed to be etched and gold embellished types. It seems that it was rare for a major Prince to buy armor lacking in gold work specifically because it would look like an ordinary common soldier. This is the reason for the increasingly exquisite artwork you see on armor harnesses from ~ 1480 - 1550. After 1550 the general decline in the use of armor seems to have led to a collapse of the broader industry in the general quality. Maybe this starts even as far back as the 1520's. That is when armor (gradually) starts to become something of a luxury for princes.

I think by that point all of the major armor producing centers are basically Royal or imperial enclaves, like in Austria and also at Grewnwich where Henry VIII set up foreign armorers to make kit for his armies.

Jean

System D'Armes Historical European fencing in New Orleans

Essays on Hroarr

Introducing the Codex Guide to the Medieval Baltic
View user's profile Send private message
James Arlen Gillaspie
Industry Professional



Location: upstate NY
Joined: 10 Nov 2005

Posts: 510

PostPosted: Fri 13 Oct, 2017 3:31 pm    Post subject:         Reply with quote

Lorenz and Jorg Helmschmid were not active in the 1430's, but their father Jorg was; if they had been, their careers would have spanned over 70 years. We know nothing of Jorg senior's work.

Quote:
Also, I seem to remember that Milan was already shifting to parade armor, steel but usually air-cooled, by the early 1400's as Augsburg began to gain control of the armor-for-warfare market. Parade armor was more lucrative in general anyway.
Not correct. The Italians did not abandon heat treating till c. 1500, probably to increase reliable ballistic resistance while keeping costs down. The German centers did not displace Norther Italy until the Italian Wars had thrown things into a more chaotic condition, which gave the German Centers a window of opportunity. Further, Flemish armour was often bought by the English. The French had good platers, mostly ethnic Italians or their descendants that had migrated north.

Most munition armour (almost all) was made of highly refined wrought iron, about the same in strength as mild steel. The exceptions were mostly Italian in the 15th century, and some munition breastplates out of Innsbruck, made by masters doing production runs of munition armour (yes, they did that sort of thing from time to time). The steel stuff could have a variety of heat treatments. Medium carbon steels with a fine pearlitic microstructure should not be discounted; they are very tough and springy, though with a lower surface hardness and a bit less memory than a tempered martensitic steel. I have often thought about offering it as an option for people on a budget that does not allow for the full two stage heat treatment.

Slack-quenched Italian steels could be incredibly tough, likely due to the presence of bainite.

Toby Capwell, in his book on the armour of English knights in the 15th century, showed that England had quite a high end industry (served only the locals, though, to my knowledge), and they were hot quenching steels as early as the 14th century, unlike the Germans, who do not seem to have started much earlier than the Helmschmids.

jamesarlen.com
View user's profile Send private message Visit poster's website
James Arlen Gillaspie
Industry Professional



Location: upstate NY
Joined: 10 Nov 2005

Posts: 510

PostPosted: Fri 13 Oct, 2017 3:32 pm    Post subject:         Reply with quote

Duplicate post removed.
jamesarlen.com


Last edited by James Arlen Gillaspie on Sat 14 Oct, 2017 7:49 pm; edited 1 time in total
View user's profile Send private message Visit poster's website
Eirik R. F.




Location: Norway
Joined: 08 Nov 2015

Posts: 15

PostPosted: Sat 14 Oct, 2017 4:29 am    Post subject:         Reply with quote

Jean Henri Chandler

Proof armour is not really a problem in all of this.

If you want to know how much kinetic energy is needed when the fracture toughness and thickness of the armour changes, you do it like this. It's from Alan WIlliams and his book: The Knight and the Blast Furnace.

First we need some basic information.
1mm steel with a fracture toughness of 235 kJ/m2 requires 55 Joules to create a 6*6 mm hole.

Wrought iron have a fracture toughness of around 150 kJ/m2.
Air-cooled low carbon steel have a fracture toughness of around 190 kJ/m2
Attempted hardened low-carbon steel have a fracture toughness of around 220 kJ/m2
Fully hardened low-carbon steel have a fracture toughness of around 240 kJ/m2
Air-cooled medium carbon steel have a fracture toughness of around 250 kJ/m2
Attempted hardened medium carbon steel have a fracture toughness of around 320 kJ/m2
Fully hardened medium carbon steel have a fracture toughness of around 370 kJ/m2

With this information we are able to calculate the coefficient for each quality.

W = coefficient
W = 150/235 = 0.638
W = 190/235 = 0.808
W = 220/235 = 0.936
W = 240/235 = 1.021
W = 250/235 = 1.063
W = 320/235 = 1.361
W = 370/235 = 1.574

Now we have all the information we need.
E1 = 55 Joules
t = thickness in millimeters
W = coefficient

This is the formula.
E2 = E1*t^1.6*W

Here is an example of how to do it. I want to know how much is needed to penetrate a 3 mm plate with a fracture toughness of 370 kJ/m2. The coefficient is 1.574

E2 = 55*3^1.6*1.574
E2 = 502 Joules

502 Joules is more than a crossbow can generate. A lot more.

Now we are going to calculate the required kinetic energy for all of these qualities when the thickness changes. We will use: 1mm, 1,25mm, 1,5mm, 1.75mm, 2mm, 2.25mm, 2.5mm, 2.75mm, 3mm, 3.25mm

First we calculate the required kinetic energy when the fracture toughness is 235 kJ/m2 so that we don't have to do that every time.
J = Joules

1mm = 55 J, 1.25mm = 78.60 J, 1.5mm = 105.22 J, 1.75mm = 134.65 J, 2mm = 166.73 J, 2.25mm = 201.30, 2.5mm = 238.27 J, 2.75mm = 277.52 J, 3mm = 318.97 J, 3.25mm = 362.55 J

Now we multiply these numbers with the coefficient.

150 kJ/m2 = a coefficient of 0.638
1mm = 35.09 J, 1.25mm = 50.14 J, 1.5mm = 67.13 J, 1.75mm = 85.91 J, 2mm = 106.37 J, 2.25mm = 128.43 J, 2.5mm = 152.01 J, 2.75mm = 177.05 J, 3mm = 203.5 J, 3.25mm = 231.31 J

190 kJ/m2 = a coefficient of 0.808
1mm = 44.44 J, 1.25mm = 63.50 J, 1.5mm = 85.01 J, 1.75mm = 108.79 J, 2mm = 134.71 J, 2.25mm = 162.65 J, 2.5mm = 192.52 J, 2.75mm = 224.23 J, 3mm = 257.72 J, 3.25mm = 292.94 J

220 kJ/m2 = a coefficient of 0.936
1mm = 51.48 J, 1.25mm = 73.56 J, 1.5mm = 79.56 J, 1.75mm = 126.03 J, 2mm = 156.05 J, 2.25mm = 188.41 J, 2.5mm = 223.02 J, 2.75mm = 259.75 J, 3mm = 298.55 J, 3.25mm = 339.34 J

240 kJ/m2 = a coefficient of 1.021
1mm = 56.15 J, 1.25mm = 80.25 J, 1.5mm = 107.42 J, 1.75mm = 137.47 J, 2mm = 170.23 J, 2.25mm = 205.52 J, 2.5mm = 243.27 J, 2.75mm = 283.34 J, 3mm = 325.66 J, 3.25mm = 370.16 J

250 kJ/m2 = a coefficient of 1.063
1mm = 58.46 J, 1.25mm = 83.55 J, 1.5mm = 111.84 J, 1.75mm = 143.13 J, 2mm = 177.23 J, 2.25mm = 213.98 J, 2.5mm = 253.28 J, 2.75mm = 295.00 J, 3mm = 339.06 J, 3.25mm = 385.39 J

320 kJ/m2 = a coefficient of 1.361
1mm = 74.85 J, 1.25mm = 106.97 J, 1.5mm = 143.20 J, 1.75mm = 183.25 J, 2mm = 226.91 J, 2.25mm = 273.96 J, 2.5mm = 324.28 J, 2.75mm = 377.70 J, 3mm = 434.11 J, 3.25mm = 493.43 J

370 kJ/m2 = a coefficient of 1.574
1mm = 86.57 J, 1.25mm = 123.71 J, 1.5mm = 165.61 J, 1.75mm = 211.93 J, 2mm = 262.43 J, 2.25mm = 316.84 J, 2.5mm = 375.03 J, 2.75mm = 436.81 J, 3mm = 502.05 J, 3.25mm = 570.65 J

Now we have all the information we need. As a rule of thumb, when the thickness is doubled, the kinetic energy required for penetration is tripled. When the fracture toughness is doubled the kinetic energy required is doubled.

If you shoot at a breastplate with a crossbow, and this crossbow generates 170 Joules the breastplate would only require an adequate thickness to defeat the bolt, and the center of a breastplate is usually thicker than the armour covering arms and legs etc. Let's say 230 Joules are enough to defeat the bolt without a serious dent in the plate. This would be possible with the following qualities and thickness.
150 kJ/m2 = 3.25mm = 231.31 Joules
190 kJ/m2 = 2.8 mm = 230.79 Joules
220 kJ/m2 = 2.55 mm = 230.19 Joules
240 kJ/m2 = 2.42 mm = 230.93 Joules
250 kJ/m2 = 2.36 mm = 230.96 Joules
320 kJ/m2 = 2.02 mm = 230.55 Joules
370 kJ/m2 = 1,85 mm = 231.65 Joules

It doesn't really matter if the breastplate is made of wrought iron or low carbon steel when 'proof testing'. Thickness matters. The problem is the side of the helmet and breastplate and the parts covering arms and legs. When these plate parts have a thickness from 1 mm to 1.7 mm, arrows, crossbow bolts, a lance and bec de corbin can penetrate them if struck perpendicular to the plate.

I hope this put things into perspective.
View user's profile Send private message
Jean Henri Chandler




Location: New Orleans
Joined: 20 Nov 2006

Spotlight topics: 1
Posts: 1,042

PostPosted: Mon 16 Oct, 2017 11:12 am    Post subject:         Reply with quote

Hi Eirik, nice post. Some useful data there.


When I mentioned 'proofed' armor, I am not referring to the actual quality of the armor. We can only really know that by doing tests of the type Alan Williams did.

Rather, I'm referring to the documentary side of the research. The court records, accounting records, letters, chronicles, histories, manuals and so on that have survived from the era. Presumably there is some overlap between the 'of proof' classification of armor and the higher quality heat treatments of the actual armor itself, but we can't say how much overlap. nevertheless some literary data may shed a bit of light on the discussion.

My main area of research is in the late medieval Baltic. Broadly speaking (always dangerous to do in the hyper-complex Late Medieval environment) In town records from cities like Gdansk, Prague, Wroclaw and Krakow, and the records of the Teutonic Order, the term "of proof" seems to have been a distinct marketing and military-organizational category for armor. This term or equivalent is mentioned both in descriptions of market prices and it was noted in inventories of guild armories, the armories of Hanseatic Kontor, and Teutonic Knights castles, among others. Specifically armor from Augsburg, Milan, and Nuremberg seem to be selling points as a sort of brand-name. For example they will say "Harness of Augsburg" or "Harness of Milan".

So for example, in one inventory from the 1430's we can see the following prices:

Mail 'haubergeon' from between 2 and 7 'zloty'
Milanese harness 4 zloty (roughly 4 gulden)
Milanese harness "of proof" 7 zloty, 4 kreuzer

The source for these is from Uzbrojenie w Polsce średniowiecznej 1350-1450, “Armaments in Medieval Poland 1350-1450”, Andrzej Nadolski, Polska Akademia Nauk, Instytut Historii Kultury Materialnej, (1990),

A sword for 20 kreuzer (or about half a mark)
A crossbow (exact type not indicated) 1 mark
A 'platendienst', which I gather is a type of coat of plates, 12 kreuzer
Cuirass with pauldrons, 39 kreuzer (just less than 1 mark)
Nuremberg half armor 'of proof' 90 kreuzer (close to two marks) (also referred to as 'black armor' at the same price)

The source for these is a spreadsheet with a lot of prices from Lubeck, Gdansk, Krakow and Torun from 1420 -1440

For comparisons, some other prices:

Bushel of flour 6 kreuzer
side of bacon 1 mark
Cubit of fine linen 30 kreuzer
Pair of new shoes 16 kreuzer
3 tons of beer, 1 mark

These are from "The Hanse, History and Culture" Johannes Schildhauer, Dorset press (1988)

This is a rough translation of an excerpt from a letter by Matthias Corvinus regarding his "Fekete Serege", the famous "Hungarian Black Army"

"(...) the military here divides to three orders: the first of these orders consists of the heavy cavalry; these wish for 15 golds [gulden / guilder] every quarter of a year after every horse, otherwise they won't come here. The other order of the light cavalry, whom we call hussars; these want 10 forints [florins] a quarter of a year after every horse, otherwise they won't come here. The third order consists of the infantry, and there are different classes distinguished: as there are light infantry, others are heavy infantry, and again others, the shield-wielders. The light infantry requires 8 golds per person a quarter of a year, the heavy armed and the shield-wielders, since they can not carry the crossbows and pavises without varlets and servants and since they must keep these children out of necessity, they want to keep these to the crossbows and shields with the payment of two people. Apart from these, there are gunmen, who know their way around guns and Pistala (hand gonnes), but neither can they be used for shooting affairs so sedulously, nor as well as the infantry, thus only after the shield-wielders, in the beginning of the clash, (...) and also, they are the best for the siege or protection of castles.”

– ( Mathias' report to his father in law, Ferdinand, king of Naples, 1481.)

Here is how I break that down: The shield bearers, gunners and crossbowmen get paid double, because of all their servants and assistants. That means the pay breaks down as follows:

Type Quarterly/Annual pay
Heavy cavalry / lancers 15 / 60 florins
Light Cavalry / hussars 10 / 40 florins
Light Infantry 8 / 32 florins
Heavy Infantry 16 / 64 florins
Shield Bearers and crossbowmen 16 / 64 florins

Even a peasant in Poland could make 30 zloty (roughly same as a florin) per year above and beyond his regular income. A mason working in in a small town in Silesia received 35 Prague groshen per week in 1450, equivalent 2 marks per month or 24 marks per year. One middling level merchant in Augsburg in 1440 spent over 900 gulden on his daughters wedding.

So to me, for regular people good armor while not cheap, was definitely affordable, at least in the more urbanized zones. Prussia was pretty urbanized by medieval standards, much more than England or France. Considering how much emphasis authorities were putting on wearing armor in the 14th-15th centuries, I think most professional and semi-professional (militia, part time mercenaries etc.) fighters whose role warranted the investment would have decent quality armor, at least in the wealthier and more urbanzied zones like North Italy, Flanders, South Germany, and so on.

Granted, the Fekete Sereg was one of the best paid armies in Europe, and even they didn't always get paid on time or at all when they were supposed to. But even if you halve the pay listed above, any of those guys could afford proofed half armor if they wanted it, or even a proofed harness though probably only cavalry would wear that.

Even a wealthy peasant or simple artisan could buy proofed armor, and it seems that for artisans at least this was not unusual - they were under pressure to get the best equipment they could afford from their guild and town authorities. All citizens in the towns I've studied were required to own armor as a condition of citizenship.

A very poor person who had some income over subsistence seemingly could afford the cheapest armor like a platendienst or a simple cuirass if they felt like it was important. There is also occasional mention of 'munitions grade' armor which is even cheaper, but seems to be considered below 'field' military grade (the type of armor the Teutonic Knights would allow static / emergency defenders of an abbey to use for example but not for field troops).

I will leave this early 16th Century painting (by Cornelis Anthonisz) of a rather grumpy looking Amsterdam militia for decoration of the post.




Jean

System D'Armes Historical European fencing in New Orleans

Essays on Hroarr

Introducing the Codex Guide to the Medieval Baltic
View user's profile Send private message
Jean Henri Chandler




Location: New Orleans
Joined: 20 Nov 2006

Spotlight topics: 1
Posts: 1,042

PostPosted: Mon 16 Oct, 2017 11:17 am    Post subject:         Reply with quote

I also know from Venetian craft guild records that they had two categories of "proof" for armor going back to the 13th century: tested by the piccola balestra, and tested by the grande balestra. The dents would be marked. Later pistols were used, as I'm sure you are aware.

So that is at least three standard categories, regular armor, proofed light and proofed heavy. And also munitions grade for a 4th category.

What this actually translates to in terms of carbon content and hardening or toughening, I can't say of course.

j

System D'Armes Historical European fencing in New Orleans

Essays on Hroarr

Introducing the Codex Guide to the Medieval Baltic
View user's profile Send private message
Michael Beeching





Joined: 22 Jan 2014
Reading list: 2 books

Posts: 147

PostPosted: Tue 17 Oct, 2017 10:07 am    Post subject:         Reply with quote

This is slightly tangent to the original theme of the thread, but I think it is still relevant. Recently, NOVA produced a rather good documentary titled "Secrets of the Shining Knight," which aired just a few days ago this month:

http://www.pbs.org/wgbh/nova/ancient/secrets-shining-knight.html

I suppose you could think of it as, "how can we make medieval steel plate today" as opposed to "what modern materials are equivalent to medieval steel plate." Basically, I get the impression that if you want medieval steel, you really have to make it yourself, and that will require an immense amount of time, labor, and tooling to achieve.

Some things to note in the documentary:

1. They test a modern "munitions grade" peascod breastplate which is either not heat treated or cannot be effectively heat treated. It is made of 16 GA, and a musket ball passes right through.

2. The armor subject to review is basically early renaissance, but the documentary refers to it as medieval - it's kind of annoying.

3. Some of our favorite chaps are featured in the documentary: Rick Furrer (previously featured on "Secrets of the Viking Sword"), who is responsible for making the steel; Michael Pikula makes a brief appearance, and Toby Capwell is available for some commentary. I've never heard of the featured armorer before, though.

4. The reproduction armor does not seem to have as good a grain structure as the original armor did, but was resistant to musket fire at short range.
View user's profile Send private message


Display posts from previous:   
Forum Index > Off-topic Talk > Modern equivalent steels for medieval armour plate
Page 1 of 2 Reply to topic
Go to page 1, 2  Next All times are GMT - 8 Hours

View previous topic :: View next topic
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum






All contents © Copyright 2003-2017 myArmoury.com — All rights reserved
Discussion forums powered by phpBB © The phpBB Group
Switch to the Basic Low-bandwidth Version of the forum