The Armour Archive

What's the difference between stainless and mild steel for armouring? I was browsing the truehearth armoury website and noticed that alot of pieces are offered in a choice of either metal, with stainless costing substantially more.
Is stainless any tougher than mild in terms of wear and tear, or is it just harder to work with? Overall, which do you think is better for armouring with?

Stainless is actually a steel alloyed with something else (chromium) for example. It is also heated to a higher temperature to drive out impurities. Stainless is "harder" than mild steel of the same thickness, so it's harder to move when you're shaping it (it's also harder to dent when you're getting hit by gorillas wielding rattan). Stainless is also more expensive to purchase than mild. All of this makes it more expensive to purchase armour made out of it.

Which is better? That depends on what you want.

Benefits of stainless.

Harder to dent
More protection per ounce of weight
Less maintenance

Downsides of stainless

Can end up making one look a bit like a Cylon from Battlestar Gallactica. (Sometimes in some forms and finishes, stainless is just TOO shiny)

Benefits of mild steel.

Easier to work (cut, grind, shape and polish)
Cheaper than stainless

Downsides of mild

RUST RUST RUST and let me say again RUST (Keeping mild steel rust free can be a trick especially if you live in a damp climate)
Dents more easily than stainless of the same thickness

Other than that there's not much difference, a pattern that works in mild will work in stainless and vice versa.

Oh, one other thing about mild steel it comes in two basic varieties, hot and cold rolled. Hot rolled has a dull grey mill scale on it that you may end up having to remove. If you don't remove it, it helps protect the metal from rusting somewhat. Cold rolled is brighter in finish when you buy it, but has a bit more tendency to rust.

That's my dissertation on comparing steel types. It could get much more detailed, but those are the basics.

Addition to above:
Stainless, being a harder material, is often more prone to fatigue cracking at stress points like where wings meet elbow and knee cops.

Stainless also eats up cutting tools and saw blades faster than mild so the cutting cost goes up.

A good armorer will have 2 sets of flap wheels and buffing wheels so the ones used on mild steel don't leave a residue on the stainless.

Happy pounding,
Sean

"It is also heated to a higher temperature to drive out impurities."

Say *what*?????? it may have a higher melting/forging temp but that is more likely based on the presence of the chromium carbides that have to go into solution. *Nothing* to do with impurities.

All steels can be specified for low impurity content (save perhaps A36 which is what you generally get when you buy "mild steel" but isn't---A36 is a mechanical spec---35 Kpsi nyield strength rather than a content spec); But high purity specs are very expensive! You can spec steels that cost more than silver if you want/have to!

Thomas

Thomas, I'm not talking about when you work it, I'm talking about when it is extracted from the iron ore at the foundary.

When the iron ore is smelted, it's heated to a higher temperature to drive out impurities ...

Stainless is not made from ore. Stainless is the alloying of steel with other elements and takes place *after* the smelting part.

I still don't get what you are trying to say. Can you refer me to somewhere that says this so I can see what they say about it?

(If you want low impurities vacuum melted steel is a step in that direction)

Thomas

I was dithering about buying my first helm (for SCA heavy combat) deciding between a nice shiny store-bought stainless bascinet and a mild steel spangenhelm custom-made to fit *me* by a friend.

Somewhere on the Armour Archives, someone pointed out that the extra mass of the mild steel was a feature, not a bug, since the inertia of the extra mass meant that less kinetic energy was transferred to my head.

For body and limb armour, maybe this is less of an issue, but I decided to go with the mild steel spangenhelm. The rest will be disguised "smurfhide", with the intention of replacing it bits at a time with some kind of steel.

BTW Amanita - Are you by chance a Ruantallan SCAdian?

stainless,she..has...no...soul........

But she last and last and last and still look good



Dragos

Put into another context. I spent 14years of armouring trying to do as little as possible with stainless because it felt like crap to work. The cutting, shaping and polishing were all more drawn out and less satisfying.
The material cost was more then twice as much and the issues of stress fatigue occassionally reared up and said "hi".

Then I bought a boat and needed to start doing a LOT of work in 316 stainless for the refit on it.

NOW I KNOW I HATE WORKING WITH THE STUFF.

I am pretty damned good at it, but even for a project I love as much as the bot. I HATE WORKING WITH FRIGGING STAINLESS Mind you the fact that most of what I am doing is in the 4mm and thicker range does not help indear it to me.



But it CAN do stuff that other steels just don't, so you use it when you need it.

Sasha

Thomas,

I'm not disagreeing that stainless is an alloy of steel and other materials, but my understanding from the guys at Siskin Steel was that in addition to the alloying process, when the steel was originally smelted from the iron ore if it was going to be used to make stainless it was smelted at a higher temperature to drive off more impurities in the ore though this may have had as much to do with facilitating the alloying process as anything else.

All steel starts from iron ore regardless of type.

There are lots and lots of different kinds of steel, distinguished by a number of things including;

alloy mixture
carbon content
founding process
finishing process
shaping process

When I used to work at a toolsteel distributor (many years ago) we had whole books full of nothing but steel varieties, and oh you guys would have LOVED to have gotten access to our warehouse.

Servus!

Simple - stainless will not rust. I like mild, but it's almost impossible to keep well-maintained with the frequency that I use my armor. I also don't have a bevy of willing squires and men-at-arms to assure that my suit is always in tip-top shape

Seriously, people like Ugo have a point - stainless looks wrong as it is too "bright" and it's harder to work with. If over polished (easily done) you do look like a Cylon (particularly if you have a t-slot barbute!) and that should be avoided at all costs.

As for the mass issue - I don't think that is such a big deal if you don't start going with thinner sheets of stainless to offset the pain it is to work the stuff in mild steel thicknesses.

first off stainless can rust depending on the type.

as for the mass of a helm there is little differance between stainless and mild of the same guage.

as to fatiuge and cracking stainless generaly has differend tempering processes almost like aluminum but it depends on the type.

I mostly work in stainless. Stainless is more difficult to move and shape than mild. It resists making compound shapes without serious persuasion. When I get the chance to work on mild I have to hold back significantly on my strikes. I have ruined many pieces when I forget that. Especially rolls. Mild feels like working with butter after stainless. I also need to re-polish my hammer faces much more often with stainless.

Chris

Each have there place. I myself like working mild, but stainless gives me more of a challenge, to see if I can do in stainless what I can do in regular steel. and now I'm starting to work with spring steel.

By Public demand, with hammer in hand

AB Hammer

On the making of stainless steel: Cailean , I asked over at the blacksmiths virtual junkyard, http://www.keenjunk.com/junkyard.htm, where a couple of metallurgists hang out, about the making of Stainless Steel.

They seemed perplexed about your "higher temperature" comment too and gave a short explaination of how SS is made.

Reading that I would guess that your comment might refer to the use of electric arc furnaces for the melting and alloying of stainless. However while the temperature of the arc *is* higher, the temperature of the molten metal is not raised above "normal" melting temps. (just like the temperature of the gas flame on your stove is several times that which your food cooks at.) The electric furnace is a "cleaner" method of melting and it combined with working in a vacuum can result in very clean alloys, of which regular stainless is not a shining example of. (sorry!)

They say it much better and I commend their posts to your attention.

Our local smithing group got a tour of a steel melting facility that used electric arc furnaces, three 16" electrodes and 20-40 *THOUSAND* amps running on each electrode (three phase) very impressive and the closest I'm liable to get to hell while still alive! The tour was in the middle of the night cause the electric rates are lower then...

Thomas

Thomas, thank you for the information, I will happily stand corrected. I was basing that on comments made by the metallurgical people at one of the vendors I dealt with (many years ago) who made some issue of higher temperatures though I may have misunderstood the import. I'm a software guy not a metalurgist.

I do appologize to one and all for any misinformation I may have inadvertantly passed along.

Regards,