[Cutting-Edge Armor Design] Real World SCA-legal Armour and Ballistics Armour

[Icelander]

Originally Posted by seycyrus

I will do my best to answer the earlier question in a later response. Note, I do not pretend to know how to equate the skillsets I see, into Gurps terms.

If you can be specific about what they actually know how to do, how they learned it and examples of where they could have practised it before, I think I should be able to translate it into GURPS skills.

Originally Posted by seycyrus

When I said "small scale", I did not mean in terms of production quantity. I am referring to the size of the parts produced. They have problems making quality pieces much larger than those needed for tension and compression testing. We are talking about pieces on the order of inches.

[...]

My comment on AM was meant to convey the "no applications in this project" attitude.

There are no commercial units available which could produce ballistic grade armor. If there was a breakthrough in the future, the cost would be more on the order of hundreds of thousands of dollars.

Ah, well, looks like hopes for a futuristic manufacturing process are dashed. Have to make do with a new method of hardening steel alloys more cheaply and easily, instead of an armour printer partway to Star Trek replicators.

Originally Posted by seycyrus

I'm afraid not. The joining of AM manufactured components to other materials remains one of the larger challenges.

What is a good way to do it?

Assuming that you wanted to link together multiple pieces of steel alloys that have been hardened to BHN around 500 and are tough enough to make working with them really hard. You'd use softer steels for any part of the armour which required more complex shapes, but you'd want the breastplate to be one piece, even if not all of it was made from the same kind of steel.

Note, I'm assuming that using flash bainite to harden steel alloys that are easier to work with will eliminate the problem, as then the breastplate could simply be made as one piece (or at least the pieces connected before hardening).

I'm just wondering if you could get an extreme level of ballistic protection over the vitals by using gently curving steel plates of a hardness much higher than anything you were prepared to work with for areas requiring more complicated shaping.

Or, for example, using titanium alloys or composites as the interior (and not visible) layer of the rigid armour, with high-quality, hardened steel as simply the outer layer. That would also require a way to combine different metals into a solid breastplate, somehow attaching them to each other, despite working with materials that would be impossible to cast and retain any of their desired qualities and at least extremely challenging to smelt.

How do you make an armour with an inner layer of titanium and an outer layer of steel, for example?

Or whatever modern MBT armours are made out of, as that seems to be several different materials somehow bonded together?

Is it something any workshop can do or an insanely expensive and hard thing to do with materials of this strength, something only huge military-industrial factories do?

[Rupert]

Originally Posted by Icelander

What do you think about the bainite flash treatment Dan Howard mentioned?

Likely to work as advertised?

Any predictable unforeseen disadvantages?

How practical for a project like this, i.e. building armour which looks medieval-esque, but provides rifle protection over as much of the body as can be done without making it any clumsier than the best historical field plate?

The biggest question I have is "How thick can a sheet be and still have this work?". the rapid heating and cooling is likely to be quite difficult to manage all the way through a thick sheet. The question is how thick does a sheet need to be to count as 'too thick'? My cut feeling is that serious vehicle armour will be out of reach, but body armour is probably in reach.

Anywhere you want your protection in other shapes than flat or very gently curved plates, though, working with these high-hardness steels is more trouble than it is usually worth, even if they would technically give better DRs, especially against APHC .50 BMG or maybe anti-personnel auto-cannon fire, than the alternative.

IF you're really serious about protection against bullets and want to use steel, face hardening is still a viable option. However it's very expensive compared to homogeneous sheets, and I suspect that the technology lags behind that of homogenous armour and laminates because the primary use for it was large warships and nobody's trying to armour them against heavy AP shells and bombs any more.

[DanHoward]

Originally Posted by Rupert

The biggest question I have is "How thick can a sheet be and still have this work?". the rapid heating and cooling is likely to be quite difficult to manage all the way through a thick sheet. The question is how thick does a sheet need to be to count as 'too thick'? My cut feeling is that serious vehicle armour will be out of reach, but body armour is probably in reach.

Historically, inconsistent heat treatment problems were solved by using duplex and triplex constructions.

[Icelander]

Originally Posted by Rupert

The biggest question I have is "How thick can a sheet be and still have this work?". the rapid heating and cooling is likely to be quite difficult to manage all the way through a thick sheet. The question is how thick does a sheet need to be to count as 'too thick'? My cut feeling is that serious vehicle armour will be out of reach, but body armour is probably in reach.

Vargas is probably going to want a pretty thick armour plate for himself, the result of having supersoldier ST for his weight. He might go as high as 1/4" for really vital areas. If he has to, that is. It would be pretty useful for him to have Level IV protection*, with an inner layer of the most advanced tailored soft body armour and outer layer of authentic-looking steel armour plate, most likely hardened as much as practical.

I think Dan Howard has mentioned real armour of proof where the thickest part was 7-8 mm, so it would be theoretically possible. More likely, of course, is that the combined thickness of Vargas' multi-layered protection will reach such awesome bulk where practical on his body, but the outer hardened steel plate might not be more than 1.5-3 mm over many locations.

*Mexico issued the G3A3 and G3A4 rifles for decades and they are still officially in service with many less front-line troops. Given than one-eight of the Mexican military deserts per year and many of them take their rifles with them when they do, getting a rifle with 7.62x51mm ammunition on the black market is hardly a challenge for any rival cartel. Obtaining APHC ammunition is more complicated, but hardly so impossible that the threat can be entirely ignored.

Originally Posted by Rupert

IF you're really serious about protection against bullets and want to use steel, face hardening is still a viable option. However it's very expensive compared to homogeneous sheets, and I suspect that the technology lags behind that of homogenous armour and laminates because the primary use for it was large warships and nobody's trying to armour them against heavy AP shells and bombs any more.

In GURPS terms, would face hardening using TL8 methods offer comparable DR advantages by weight and/or thickness over RHA steel as the percentage increases in Dan's quoted article implied for the flash bainite process?

And how expensive would doing it be?

[Icelander]

Originally Posted by DanHoward

Historically, inconsistent heat treatment problems were solved by using duplex and triplex constructions.

Yeah, I've been wondering how you do duplex or triplex construction using modern alloys of ultra hard steel and/or various exotic alloys or composites, where heating up the materials enough to forge them, once they've been made (possibly by a sub-contractor to your specifications), would seem to destroy the properties you wanted them for.

[DanHoward]

Originally Posted by Icelander

I think Dan Howard has mentioned real armour of proof where the thickest part was 7-8 mm, so it would be theoretically possible.

The heaviest extant cavalry armour is around 9 mm. The heaviest infantry armour is around 6 mm. I'm guessing that the heavier plate was too fatiguing to wear on foot.

[Icelander]

Originally Posted by DanHoward

The heaviest extant cavalry armour is around 9 mm. The heaviest infantry armour is around 6 mm. I'm guessing that the heavier plate is too fatiguing to wear on foot.

Supersoldier strength, more than human muscles will allow for their weight, makes bulk a lot more significant consideration than weight, at least for Vargas personally.

I'm guessing Vargas' ST at anywhere from ST 18 to ST 25. He also has supersoldier HT, probably HT 14+. Total weight of 100+ lbs. for his harness (with 12 to 15 lbs. for a cooling system) would mean fighting at Light Encumbrance, at least, especially when carrying weapons and ordnance, but real people tend to fight at Medium encumbrance anyway, so it's not like he'll be unable to.

As long as the bulk doesn't restrict mobility anywhere, which is one of the things for which he'll need someone familiar with historical armour design, human ergonomics and fighting in historical armour on the design team. And where I need input from such people on the forums, to ensure that no part of his body is armoured with more thickness than would allow full range of motion and that the design and construction are plausible enough in terms of allowing both SCA/HEMA/HMB fighting and modern tactical shooting in it.

[Rupert]

Originally Posted by Icelander

Yeah, I've been wondering how you do duplex or triplex construction using modern alloys of ultra hard steel and/or various exotic alloys or composites, where heating up the materials enough to forge them, once they've been made (possibly by a sub-contractor to your specifications), would seem to destroy the properties you wanted them for.

In the modern world, I assume you'd use some kind of glue/cement if welding wasn't practical.

As for face-hardening, it's main advantage is that you can harden the face without regard for its resilience, as the back of the plate provides that. In turn, the back of the plate need not be very hard, as the face provides the raw hardness.

TL6 and TL7 face-hardened plate was slowly baked in a furnace with carbon held against the front face (or blown over it as a carbon-bearing gas) so that the plate absorbed carbon, creating a plate with different levels of carbon front to back. The plate was then hardened, followed by the back being annealed to reduce hardness and improve toughness. Face-hardening was a replacement for compound armour where multiple plates with different characteristics were welded together.

I expect you could design a face-hardening regime for some modern alloys that would produce the same effect whilst taking advantage of the alloy's superior general characteristics. That said, a cursory search suggests that in plates under 3"/76mm thick face hardening vs simple RHA only adds 3-8% resistance.

[Polydamas]

Originally Posted by Icelander

Here is something that can be worn under any kind of armour eventually emerges. Mind you, Vargas and maybe even some of his retinue would certainly replace the Improved Kevlar with Ballistic Polymer tailored to their bodies, which would probably require Stylish, as they would have to obtain it from some custom-maker like Miguel Caballero.

Ok, I was finally able to buy Pyramid 3-85 and have a look.

Under Low Tech's assumptions, generally plate armour for the limbs will be DR 3-5 (average thickness 1-1.5 mm), armour for the torso, neck, shoulders, and head DR 5-8 (average thickness 2-3 mm). Maybe a superman like Vargas could double that thickness.

My bracers (covering what CEAD calls Arms minus Shoulders) are 4 lbs each. Cutting-Edge Armour Design would give them DR 7 in Hard Steel with the Plate modifier (DR 7 x 2.8 sf x 0.4 WM = 7.84 lb). So in theory, Vargas could have arms and legs which will stop 5.56 x 45 mm from a short barrel. I am not sure if 2-3 mm of shaped and hardened 1045 or 1050 spring steel, 4130 chromoly, or 410 stainless will really do that, but maybe if they are smart about putting the thickest metal in the parts that go towards the enemy when he has a rifle at his shoulder ...

Your figures for underarmour don't look crazy, and there are sports fighters who like a whole padded legging under their legharness.

[Polydamas]

Originally Posted by Icelander

Any suggestions for websites other than Armstreet?

Icefalcon (kind of ugly but takes a pounding, run by a SCA and IMCF fighter) and Armstreet (lots of bling, not always the strongest/most protective) are fine places to start. Lorifactor carries medieval bling, but more fancy belts than armour.

Armory Marek does some etching and gilding http://armorymarek.com/
ArtArmor -> ArmorySmith in Ukraine http://www.armorysmith.com/ has statistics and leans towards HMB armour

Moving into the kind of people who have a 1 to 3 year backlog, Tomala, Piotr Feret, and Roman Terechenko of the depends-on-who-you-ask-ian Crimea (he just has a FB page).

Grettir the Slow is probably the most 'high tech' gauntlet maker who talks about his work in public: I think he uses computer-controlled kilns and other tools from his background as a machinist.