Why Not Use Stainless Steel For Segmentatas

[chris]

I have not read the metallurgical study but it would be interesting. I have reenacted various periods for over thirty years and I have found some things to be universal. One is that never say never. I remember Civil War reenacting years ago when several "purists" began to dicuss that uniforms were made this way and not that way etc. I have a rather extensive uniform collection including some original Civil War uniforms. I stated that what they claimed as an absolute was not the case. I solved the argument when I asked them if they had ever handled any original Civil War garments. They said no. I then showed them the uniforms in my posession and said to them, that there is seldom standardization in hand made garments. The second thing I have have found to be true is just what Magnus stated. We have to do the best we can with what is available and try to "mimic" the original as much as practical. Fullered, 1800's wools are no longer commercially available to most people and so we must rely on modern wools. Antique and even ancient padding materials are no longer manufactured, so we use what appears and feels as close as we can get. From my perspective, reenacting is as much trying to get a feel for what the individuals went through as well as what the wear or how they appear. Cleaning rust from iron armor was probably an almost hourly ritual in the moist European environments even with ancient rust preventatives. Getting rust out of pits and stopping the rust bloom without sand blasting and sand paper, wire wheels etc. must have been a real laborious chore. I have tried numerous rust preventatives and have found that my armor will exhibit rust bloom just from humidity changes and handling. As far as carbon content of ancient armor there would need to be procured a small section of the actual unaltered metal to perform a wet chemistry test (note that oxidized iron contains iron oxide and may suffer from changes in the alloy content and grain structure such as carbonization, which is migration of carbon into the steel or iron from carbon dioxide in the atmosphere). This is called age hardening and has been noted in older structural buildings and bridges where the metallurgy has changed due to atmospheric conditions. I am not an expert in forensic archeology but I would think that due to extreme age and exposure, we may never fully know the true properties of ancient Roman iron. Thus, I think that low carbon steel probably catches the visual aspects of ancient Roman iron, although modern steel would behave better in combat situations due to improved tensile and yield properties. I would think it would be more likely to have rivets pull through the steel while iron would crack and suffer from spalling of the rivet area due to being more brittle. I also think from a practical standpoint, trying to punch nice round rivet holes in wrought iron must have been a true art and would require a great deal of strength, as would also the forming process with a plate that would be less prone to forming than modern low alloy steels.

[Tarbicus]

Here's a link to the article I mentioned as a brief abstract.
http://cat.inist.fr/?aModele=afficheN&cpsidt=16568175

You could sign up for a free trial of the website, and supposedly read the rest of the article.

[chris]

Based on the extract, many of my postulated theories may be true. Carborization is the result of long term exposure to atmospheric carbon dioxide that causes a face hardening of the iron or steel (The addition of carbon improves the hardness of steel). Based on the extract, one sample exhibited this phenomenon. This would indicate a sample that was exposed to the atmosphere for some time. Another sample was a medium carbon iron, not steel (realize that to produce steel, there needs to be three primary elements, iron, silicon and mangenese). This would indicate the introduction of carbon most likely due to the forging process. It is interesting that the extract does not mention any silicon. Based on the extract, it would appear that steel was unknown to the Romans due to the lack of mangenese and silicon. Thus, one can conclude, based on the extract that Roman iron ranged from a soft iron that was work hardened to a medium-hard iron due to the addition of substantial amounts of carbon. Thus "technically" using steel for Roman armor means using a material with elements introduced to the matrix that were unknown to the Romans, mainly mangenese and silicon. The same can be extended to stainless steel in which nickel and chromium are introduced into the matrix, also unknown to the Romans. BY the way, a search on the web revealed a US manufacturer that sells soft plate iron in 16 gauge thicknesses. I don't know if the RAT rules will allow me to post their web site here so if anyone is interested, I will contact the supplier for further pricing and information.

Humbly and Respectfully,

Chris

[Primvs Pavlvs]

Chris I think that 16 gauge is much to thick for regular segs. I had a Corbridge A made from 16 gauge, and it approached 27 lbs.

[chris]

I am wondering if the plates could be hammered into thinner sections, I.e. cutting out the Lorica sections then hammering them to a thinner section then trimming. It would be an interesting exercise (and I mean "exercise"). Maybe someone who does metal working could comment. This might cause other problems like work hardening causing cracking when the shapes are bent. I dunno? Maybe I can contact the manufacturer to see if 18 ga. can be rolled.

Chris

[Tarbicus]

A piece of scale armour had iron silicates present, confirmed by SEM ADAX chemical analysis. The outermost surface showed pearlite grains and hardness increased there to 438 Hv indicating surface carburising.

Other pieces indicate a carbon content. The conclusions of the paper say there were pieces of medium carbon steel, and they're very specific about that. There was warm and cold working, and partial carburisation, pearlite grains of lamellar type, separate heat treating followed by air cooling like modern processes.

[Tarbicus]

Chris I think that 16 gauge is much to thick for regular segs. I had a Corbridge A made from 16 gauge, and it approached 27 lbs.

There was definitely a mix of thicknesses over different parts of the entire seg in some cases. Thicker on the upper shoulders, and down to 18 gauge on the girth hoops. Matt Lukes is making one for me like that, and I'm dying to know if the weight distribution makes a difference. I suspect it will.

[chris]

Very interesting. So it is safe to say that the Romans used a medium to low carbon steel with some silicates present. Did the report indicate the presence of any other alloys? Copper, Manganese etc.? Carborization could occur during the forging process (rudimentory face hardening). By the way, I called the supplier and they can obtain various thicknesses of iron plate including 18 ga. They are in Illinois. It is a malleable black iron plate that can be supplied in a full range of thicknesses. I was wanting to make a new Newstead cuirass (based on Mike Bishop's plans). I have already made one in 18 ga. steel. I wonder how it would look in iron?

By the way, it is interesting to me to read the RAT. Of all of the various web sites devoted to historical reenacting, I am amazed at the assembling of world wide expertise that is expressed on this web site. I have learned more in the last couple of years about ancient history by reading these web postings than all of the years I spent in college and seminary. I am thankful that all of those who participate are willing to share their knowledge for the benefit of neophites like myself.

Respectfullt,

Chris

[Tarbicus]

Chris, check your private messages.

[Hibernicus]

Tarbicus: RLQM.com has been doing mixed guages for many many years... mix and match!

Chris: Please, post the info for the manufacture.

I have acompany in MX that can produce sheet iron but I'd practically have to by a train car load!

[chris]

The company is L&M Sheet Metal Phone #815 338-8666

Address:
13706 Washington
Woodstock, Illinois 60098

E-mail www.netwrights.com

I talked to the owner and he can supply small quantities. I asked about a few 3'X3' plates for myself and he said that he could supply them to me. I am still waiting on a reply as to 18 ga. plates and costs etc. I will post this information shortly.

P.S. Tarbicus, I sent my e-mail address to you. Did it come through?

Chris

[chris]

Oops, the web site listing is not complete. Here it is:

www.netwrights.com/landm/products.html

Respectfully,

Chris

[M. Demetrius]

Great source; I've emailed them already.

Do you know if they stock or can get square or round rod? I asked, but haven't heard back. Iron pilum shafts would be much more like the "real thing" than the cold rolled steel that's available at local metal shops. It's a lot easier to make square from round than the other way, natch.

[chris]

I will try to find out. Here is a web link to a company we have used in the past that has pure iron round bar and square bar in stock.

www.shopwagner.com

Respectfully,

Chris Dumford

[Gaivs Antonivs Satvrninvs]

Wow,talk about expertise.Chris, I'm dumbfounded by your knowledge of metals.Your previous posts are a fascinating read if a little over my head.
Still,thanks for sharing with us and thanks for the links.