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From an email discussion on steels for swords - Doug Ayen's Blacksmithing Blog [entries|archive|friends|userinfo]
Doug Ayen

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From an email discussion on steels for swords [May. 13th, 2004|07:44 pm]
Doug Ayen
(Person asks if titanium could be used for a sword, and asks opinions of different steels)


Anyway, titanium is, by itself, a light, strong metal, fairly soft, and
able to withstand repeated flexings fairly well.

It is completely unsuitable as a sword material by itself. It is way, way
too soft.

Now, alloyed with copper, aluminum, and other stuff, you can get the hardness
up to about 50ish on the RC scale. For comparison, even a mild steel can
get up into the mid-60s without too much difficulty. Still, it has a use
for diving knives, where its corrosion resistance is considered a boon.

For a "bashing" weapon, I'm guessing you're talking about the modified
crowbars of the 14th-15th centuries, the so-called hand-and-a-half swords
designed to pierce and break plate armor. Unless your opponent is
wearing titanium armor, you'll never break or pierce the case-hardend
steel of such protection, you'll just bend and eventually break the
sword.

Now, for a rapier, you seem to think that they were a light weapon. Rapiers
were actually much heavier than most other single-handed weapons, because
they were long - as much as 5 feet, with examples over 6 feet in some
extreme cases. While a titanium alloy might do well here, and certainly
be lighter than the originals, you're going to run into issues eventually
with metal fatigue. snap. game over.

For slashing, depends on the opponent. As mentioned above, any steel armor
will render the blade as useless as a club. If he's wearing leather, silk,
or other fiber armor (quite common), you'll probably have to sharpen often,
which can be dangerous in a battle, but you'll have less fatigue as they
blade can be lighter yet still have enough strength to effectively transfer
energy to the opponent.

As for the various metals you mentioned, lets take a look:

Damascus -- common European name for Wootz steel, a superplastic
ultra-high-carbon steel made via a crucible method. In it's unhardened
state it is extremely tough, yet still has enough carbides to hold a
decent edge -- most sabers were unhardened for this very reason. Hardened,
it was extremely hard, and could take an extremely fine edge, yet was
as brittle as glass even after tempering. Very hard to work, few people
make it today due to the amazing amount of work required to produce a weapon.
Basically, cast iron that can hold an edge, it's inferior to modern
steels in every way, but pretty.

Modern pattern welding is sometimes also called damascus, as it has a
similar "watered steel" look to it. This is formed by fusing layers of
different steels togethern, then manipulating the resulting billet to get
various patterns. Depending on the steels used (or even other metals,
in some instances) this can be as good as regular modern steels, or
crap that'll fall apart as soon as you try to use it. Look for mixes
that have similar heat-treating methods, or you can end up with a blade
that is flawed due to uneven expansion and shrinkage during heat treatment.

tamahagane -- japanese primitive steel made in a small furnace, containing
between .5 and 1.5 percent carbon. Really crappy stuff, to be honest,
All that folding, making a low-carbon core encased in steel, pretty
temper lines, and so on was simply an attempt to produce a blade that
wouldn't break in battle the first time it hit something or got a chip
in the edge. Looks nice, again modern steel is better.

Oroshigame. Er, this is a food grater, used for wasabi and daikon,
traditionally made of copper with a tin coating. What were you thinking
it was?

440. C 1.00 Mn .45 Si .30 Cr 17.00 Mo .50. See that 17% chromium? Your
blade will chip, and most likely break in use due to that. I wouldn't
trust it for a sword, and really don't use it for anything as it doesn't
hold an edge worth a damn. If you must go stainless, go for D2, or some
of the new CPM S30V high Vanadium/high carbon steels, which look interesting.
For a proven technology, though, stick to the known good steels:

L6. Very shock resistant, used for saw blades, has enough nickle (1.5%)
to be semi-stainless, though it will rust if not kept oiled.

A2. Air hardening, high carbon, enough chromiun (5.2%) to be semi-stainless,
but again requires some maintenance.

S6/S7 - used for jackhammer tooling, this stuff is tough, tough, tough,
and is often used for swords not requiring a razor-sharp edge.

1050/1075/1095 - very basic steels, for swords pretty much the standard
by which other steels are measured. 1095 is a bit high-carbon for sword
work, 1050 and 1075 is prized by japanese sword makers as it has enough
carbon to get and edge when water-quenched, and shows a great hamon, and
is tough due to the lower carbon content.

5160. Car springs. Very tough, holds an edge, .6% carbon, high molyebnium
content means the hardening goes all the way through the steel. My steel
of choise for many blades.

Now, personally I'm looking at doing some titanium/tool steel explosion
laminiation for some blades, but am having problems getting the permits.
Someday, though . . .

--doug
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