Heat treatment of maces -- myArmoury.com

Constantin M. · Posted: Tue 13 Oct, 2020 10:30 am Post subject: Heat treatment of maces

Greetings,

I am starting to make a flanged mace. Does anyone know if the flanges should be (surface-)hardened? I can imagine that they would take damage when hitting steel armour or other hard surfaces.

Dan Howard · Posted: Tue 13 Oct, 2020 2:29 pm Post subject:

There is nothing to suggest that maces were deliberately heat treated, though the carbon content varies wildly. Keep in mind that any functional implement was designed to be used, which means that it inevitably got damaged, and was intended to be repaired/replaced over time. Battle-damaged gear was a mark of bravery. If you walked out of a battle with your gear undamaged, you would get accused of not pulling your weight, if not of outright cowardice.

Michael Beeching · Posted: Tue 13 Oct, 2020 8:27 pm Post subject:

From a functional standpoint, I think you can go either way with a mace, at least if the mace is steel or iron. Put in another way, there are parts of a mace you might want heat treated, and there are parts you probably don't.

Consider first the parts you may not want to be hard or perhaps spring-tempered: the shaft of the weapon is probably one of them. Making an analogy to swords - which may not be a good analogy, by the way - consider those you may have seen who abuse them. There are a lot of good weapons, which used in their correct context, may be very good, despite heat treat or material deficiencies. But, under extreme abuse, they fail quite badly, often because they are too hard and do not take the shock load well. A mace shaft cannot be allowed to fail from something like that, because they are in fact part of a weapon which is made to be used in an extremely abusive manner. It is often better to bend rather than break. So, you end up with a sufficiently thick steel or iron shaft which is not all that hard - the shaft may or may not be hollow, but the width of the component is what will give it its rigidity and bending resistance. Going back to swords, the katana is kind of like that, too.

In contrast, you may want some parts hard as well. For something like a flanged or spiked mace, you might want hard points on the weapon head where you intend to strike. Hammers and spikes will be similar in that regard. All the while, the rest of the material can be softer in order to cushion the weapon, and also reduce the shock imparted to the user.

Leo Todeschini · Industry Professional

Flanged maces were very often brazed together during construction and this would be a devil to do with pre-heat treated parts and keep the treatment and a devil to do once it is assembled and for it to stay in one piece, so although I do not know for sure, I strongly suspect they were not treated and if they were, I would love to know how.

Tod

Constantin M. · Posted: Wed 14 Oct, 2020 5:37 am Post subject:

Thanks for your responses. Hi Tod, I really like your YouTube channel.

I can only speculate. The reason why I would believe flanges to be hardened is the abillity of the "edges" to bite into plates. So that there is less deflection on impact. I've done a few tests. Unhardened 90 degree edges get dulled serverely on impact with unhardened steel surfaces.

Historically I would think the mace head would be case hardened. One way would be to quench the head in a compound of horn meal and other stuff.
One fletcher described this to be one way to harden arrow tips.

On the other hand the flanges getting dull may not be a problem. I have seen historic examples there the flanges were rounded off.
Seams kinda ironic to worry about an impact weapon getting dull.

Michael Beeching · Posted: Wed 14 Oct, 2020 12:52 pm Post subject:

Further concerning flanged maces, because I quite like them, consider this: I would argue the function of the flange is not so much as to bite into the plate as it is to concentrate force, not unlike a sword blade in a sense. Unlike a sword blade, the mace head is not designed to cut. In fact, I would argue that you don't actually want it to pierce the armor - if it pierces, the weapon might get stuck in the target!

...I do not know much about historical maces, but I do have an A&A Flanged Mace. In that example, which is based on a historical example, the tips of the flanges are swelled, and they do not come to fine points. Area is minimized so as to maximize impact pressure, but the design should not get suck and will resist dulling.

The comments on case hardening are interesting, but I don't think you'd want to go about producing a mace that way. If the weapon is brazed together as Tod noted, you'd also exceed the temperatures of such joints if you attempt such a thing after assembling the mace. So, any carburization would have to be done before assembly, and concentration of the carburizing would have to be controlled. You'd only want to work the tips of the flange - the base should be softer to absorb the impact.

Tod,

If you could - because this is relevant to some other interests I have - can you determine if there is a difference in hardness between low carbon and high carbon steel which has not been heat-treated? In the case of maces here, if you could not preserve any particular heat treatment in the assembly of the weapon, could you make the striking faces harder by simply using iron with a much higher carbon content in the tips?

Dan Howard · Posted: Wed 14 Oct, 2020 2:44 pm Post subject:

Dan Howard · Posted: Wed 14 Oct, 2020 2:53 pm Post subject:

Michael Beeching · Posted: Sat 17 Oct, 2020 12:42 pm Post subject:

Dan,

Thank you for the suggestions. However, I'd like to point out that I do not necessarily have the means of procuring Tylecote's book at the moment. That said, if you happen to have a more quantifiable relation to my previous question:

Dan Howard · Posted: Sat 17 Oct, 2020 2:46 pm Post subject:

Constantin M. · Posted: Sat 17 Oct, 2020 11:09 pm Post subject:

Hi Dan,

the previous part of the discussion was about hardness of unhardened steel linked to carbon content. The chart you posted seams to be about hardened (but untempered) steel alloys.

Still:
I've been working with different (modern) steel types for a few years now (which doesn't make me an expert). Some beeing very low in carbon others very high. The low carbon steels tend to be much softer in unhardened condition. Please bear in mind that other ingredients in the alloy may have an influence.

Constantin

Dan Howard · Posted: Sun 18 Oct, 2020 2:31 pm Post subject:

Constantin M. · Posted: Mon 19 Oct, 2020 12:36 am Post subject:

First: I don't know a lot about the mechanics of work hardening.

For what I understand martensite is only formed by heat treating.

I am certain that steel without heat theating will never come close to the 60 HRC mark. Regardless of carbon content or alloy elements (not even absurd ammounts of tungsten or molybdenum).

I couldn't find exact information about the Rockwell hardness of non-heat treated steels but I assume it will be around 20-35 depending on the alloy.

Work hardening may be a good point in the general topic of hardening maces. It might be possible while not necessarily practicable. But as I said - I don't know a lot about it. Work hardenened flanges may indeed be possible but maybe to brittle.

We can conclude the topic: flanged maces were most likely not hardened (by heat theatment).

I am still curious about the latest points.

Michael Beeching · Posted: Mon 19 Oct, 2020 10:02 am Post subject:

Dan,

Thank you for finding the graph. However, I do have to agree with Constantin here - the steels in the graph seem to have been hardened, probably by quenching. When I stated "not heat treated," I should have stated something more along the lines of "steels which have either been annealed or air cooled."

The latter point is relevant to this discussion as we've already made note of certain construction techniques in historical maces. Brazing temperatures degrade existing heat treatments, and I am confident that most of the metal in a shaft and head would be preferably soft in order to survive impact shock...

...SO, the question, more clearly defined this time, is: "if I have very high carbon steel used in the striking faces of a mace, but have either annealed or air-cooled that steel either by choice of manufacturing or by consequence thereof, will that steel be harder than a similarly handled component made of low-carbon steel? Again, the key words are (or should have been) 'annealed' or 'air cooled.'"

Now, some of the modern "medium alloy steels" which would fall into the curve of the graph you posted might be air hardening, but I am inclined to think (but do not know) that many metals one might be tempted to make a mace head from (especially in a historical context) would not be air hardening and would require quenching to harden. They would then of course require tempering to alleviate brittleness, etc.

Dan Howard · Posted: Mon 19 Oct, 2020 2:08 pm Post subject:

Michael Beeching · Posted: Mon 19 Oct, 2020 8:35 pm Post subject:

Dan, the graph says "untempered" at the bottom. I do wish I knew more about heat treatment personally, but if Wikipedia can occasionally be believed, Martensite forms due to quenching. Those steels have been quenched, unless the source material from which you obtained that graph offers some form of alternate information.

I'm envious of your freshman year in high school. We did not have any offerings in metallurgy here in Indiana.

Constantin M. · Posted: Mon 19 Oct, 2020 9:56 pm Post subject:

Michael Beeching · Posted: Tue 20 Oct, 2020 6:15 pm Post subject:

Constantin,

What a fantastic, simple test! I've also wanted some information similar to this to go along with my current musings on iron age swords. So, thank you very kindly for running this.

...I do have an idea for you: if some hardness is desired in the striking faces of the mace, perhaps you could coat the other surfaces is a thick layer of clay? You of course will still have heat transfer through the metal, but it should be mitigated? It might be worth a try.

Andrew Gill · Posted: Wed 21 Oct, 2020 5:33 am Post subject:

Hi there

I'm a mechanical engineer - we studied the iron-carbon phase diagram in 2nd year undergrad (many moons ago, but I still have the textbook).

Dan, if steel consists of untempered martensite, as in your graph, it has definitely been quench-hardened by heating it to around 750 deg. C (the austinic phase-change temp) and then quenched fairly quickly to below 200 deg C. Martensite doesn't form unless this occurs, so Michael and Constantin are correct. Tempering is the process of transforming a some of the martensite back into softer ferrite containing harder particles of cementite, to make the material tougher with a slight decrease of hardness relative to untempered martensite.

I refer you to "Materials Science and Engineering: An Introduction" by William D Callister Jr" if you want further confirmation or refutation (my copy is at my office right now, and we're still working from home under lockdown, or I'd scan and post the relevant section).

However, you are certainly correct that (all other things being equal), higher carbon content will make steel harder, if both have either been heat-treated or not heat-treated respectively.

In layman's terms, heat-treating a given piece of steel will make it require more force to deform a piece of steel to the degree where it will take a permanent set (ie. bending a sword-blade so that it stays bent, or rolling the edge). That is why a quench-hardened piece of steel will be able to scratch an unhardened piece of identical composition.

Kind regards

Andrew

PS:
returning to the original question: often heat-treatment is accompanied by a slight warping of the part. So from Todd's information that the parts were brazed together, there would probably be a real danger of the brazed-on flanges cracking off, even if the joints could be protected from the heat.

(edited; tempered martensite has partly transformed into ferrite, not pearlite).

James Arlen Gillaspie · Industry Professional

I know of no published work on the hardness of mace flanges. If there is such a thing, it would be very useful to this discussion. If there is not, the contention that they were not hardened would appear to have no basis, except for treacherous arguments based on what we consider plausible. As Tod has pointed out, however, it would be tricky, indeed. What is certain is that a mace made from medium carbon steel, even if not heat treated, will hold up far better than one made of wrought iron. I have only had 16th century maces in my hands for any length of time (except for a wonderful late 15th century German example in the Royal Armouries UK reserve collection), and they had a very odd and interesting feature that I have not yet seen discussed. I will post photos as soon as I can figure out where they are. Worried