I like the
idea of this mod (overhauling metallurgy), and I especially like how wootz steel has been implemented (being called "crucible steel", and extra points for knowing about the vanadium in it), but a lot of the changes are even
less realistic than vanilla DF.
Steel from pattern-welding? How does that work? First of all, you're talking about forge-welding, with pattern-welding being a particular implementation of it. Forge-welding was used to combine a high-carbon steel with either a low-carbon steel or wrought iron to get "the best of both worlds": the hardness of the high-carbon steel without its inherent brittleness. You needed to already have steel to do this. In practice, almost all pre-Modern steel weapons were forge-welded products of steel and iron. "Pure" steel was usually not weapons-grade, and was very brittle, either due to too much carbon, or sulfur impurity in the iron. The happy medium was achieved by fusing the brittle steel with wrought iron.
It
is possible to take a bar of wrought iron, a bar of cast/pig iron, and get steel from them by melting them in a crucible, if you know how.
But this is not forge-welding. Cast iron melts at a much lower temperature than wrought iron, so this process simply cannot occur in the solid state. By the time the wrought iron is hot enough to weld, the cast iron is already molten.
This is the method Toady already implemented into DF, which is why the smelter asks for iron and pig iron. It is historically accurate and results in crucible steel, which is a better (as in more homogeneous) grade of steel than cementation steel. You've chosen to take that functionality out of the smelter and put it into a separate "crucible furnace", which is fine, although there's no logical reason why the smelter couldn't do this job: "crucible furnace" and "smelter" are two ways of referring to the same structure.
Steel from a blast furnace? That's not what blast furnaces do at all. They extract large amounts of metal from large amounts of ore, and in the case of iron ores they only make pig iron, not steel. In fact, only cast iron made at a blast furnace is
called pig iron, technically, and it tends to be as much as 4% carbon by weight. Also, historically, coke couldn't be used as their fuel, because any impurities in the coke would ruin the iron. It's important that molten iron only be exposed to absolutely pure carbon, if you want it to be worth using when you're done. Blast furnaces relied
entirely on charcoal until the early 1700s. Without a way to convert pig iron into steel (e.g. a Bessemer converter), a blast furnace doesn't get you any closer to your goal than a bloomery does, except that a bloomery
can actually be manipulated to produce bloom steel rather than bloom iron.
Your blast furnace recipe for steel is also completely imaginary. 6 flux + 6 fuel + 6 ore -> 6 steel ? Wouldn't that be wonderful! The actual weight ratios used in a blast furnace (keeping the output at 6) are: 6 flux + 12 fuel + 24 ore -> 6 pig iron. Not as impressive. Those are
weight ratios, of course, and blocks of stuff in DF are not of uniform weight. Also, 5 times the amount of flux (again by weight) worth of air would get consumed in the fire, so if you make one of these underground without ventilation, expect to die of asphyxiation.
Pig iron production doesn't require flux? Pig iron made in a bloomery (which is technically
cast iron) wouldn't require flux because the carbon monoxide produced during heating would act as the fluxing agent. But bloomeries aren't actually
designed to make pig iron; it's a waste product due to improper heating and carburization of the iron, and was thrown out with the slag. Iron itself won't melt in a bloomery, because it has a high melting point, but if too much carbon gets into it, it becomes cast iron with a much lower melting point, and suddenly you have accidental molten cast iron on your hands, which is useless without a
finery forge to convert it back into low-carbon iron. If you're making pig iron in a blast furnace -- which is how it was made on an industrial scale -- then you
do indeed need flux. Specifically, limestone. Or, if you really want, quicklime itself, which is what makes the limestone useful. Quicklime can be made by heating limestone in a kiln, and it doesn't require a very high temperature, either.
I'd like to see Ironworks overhauled to address these issues, and I have suggestions:First of all, simply remove the blast furnace. It has no place in the Dwarven technology tree, unless you want to give them a Bessemer converter.
Second, remove "pattern-welding", as it currently exists. It can be put back in later, when it's implemented correctly.
Third, consider these ideas:
The bloomery: The oldest (as in prehistoric) way of making wrought iron, and until very recently (last few centuries), the only good way.
A bloomery takes 2 iron-bearing stones and 1 fuel and converts them into either 2 wrought iron, or 1 wrought iron and 1 pig iron, depending on the skill of the furnace operator. Fuel or magma is also needed to power the reaction, though the iron is not molten at any point in the process: it's a solid-state extraction. No flux is needed because the bloomery produces carbon monoxide (a flux material in its own right) from the incomplete combustion of the fuel. However, it's also poisonous (historically called "white damp"), and so the bloomery should go outside for ventilation.
In reality, the bloomery would produce spongy
bloom iron, with an occasional accidental byproduct of cast iron. I'm going to abstract and pretend the conversion of bloom iron to wrought iron happens on-site with no additional investment, which is nearly true: all it takes is a sturdy Dwarf literally beating the slag out of it with a hammer. Hard work, yes, but inherently Dwarfy work.
Because the bloomery achieves temperatures as high as 12,000 Urist (the same temperature as magma), it must be made out of a magma-safe material.
If the bloomery is implemented, then iron should no longer be smelted at the smelter at all, and also you can ditch the "finishing forge". In this case, there's no distinction between "iron" and "wrought iron": all in-game iron is wrought iron unless otherwise noted.
The finery forge: Basically a re-bloomery for pig iron. It takes 2 pig iron and 1
charcoal and converts them into 2 wrought iron. In this case, the process
does actually melt the iron, so it's not exactly like a bloomery.
Historically, the finery forge wasn't invented in Europe until around the time Columbus was contemplating sailing west to his death (as far as he knew) in the late 15th century. However, China had already known about blast furnaces and finery forges for two millennia by then.
I know it seems strange that taking high-carbon iron and then adding charcoal to it should result in low-carbon iron, but the charcoal is not part of the reaction; it is just fuel. This forge
cannot be magma-powered: finery fuel
must be charcoal, because the chemical impurities in coke will ruin the molten iron, and
magma doesn't actually get hot enough to melt iron.Because the finery forge gets slightly hotter than a bloomery, and thus hotter than magma, magma-safe material won't suffice to build this forge: you will need
refractory bricks. See below.
Case-hardened weaponry (aka cementation aka carburization):Rather than making steel at a smelter or crucible furnace and
then turning it into a weapon, a weapon
already forged of wrought iron can be
hardened with a steel shell at a forge by packing the blade in an airtight
refractory box (see below) with charcoal, coke, hooves, or horns (but not bones: too much calcium), and heating it to around 12,000 Urist for several hours. This gives you back the original weapon, except it's made out of
hardened iron, which is intermediate in quality between wrought iron and steel. If you case-harden iron long enough (with a box designed for longer use), it becomes cementation steel all the way through. If you case-harden it for
too long, however, it becomes brittle cast iron. A good weaponsmith will produce fewer accidental cast iron weapons, which are useless in combat. Note however that only the cementation steel process can result in accidental cast iron: the hardened iron process always succeeds, and weaponsmithing skill simply makes it faster.
This method can also be used on wrought iron bars to produce steel bars, but it is done at the smelter (or crucible furnace, whichever), and the skill check is furnace operation rather than weaponsmithing, and works like (actually
is) the cementation steel process: it can accidentally result in cast iron with low skill.
This isn't the sort of thing a Dwarf would want to do indoors: if the box leaks, you will die of "white damp" poisoning just as with the bloomery. In fact, what is inside the box basically
is a little bloomery.
Refractory bricks:Ever wonder what those forges are actually made of? Ever find it suspicious that you could make them out of any "fire-safe" rock, even ones with melting points lower than iron? The answer is refractory bricks.
Refractory bricks are made in a kiln, as they are basically ceramics. There are several types of them.
Glass furnaces can only be made out of
high-grade refractory bricks, because glass-making actually requires higher temperatures than metal smelting: in excess of 13,000 Urist. High-grade bricks can only be made out of adamantine (if you have some lying around...), or dolomite, or periclase. Historically, periclase (magnesium oxide) was used for this. Corundum
would also work, but it's not in the game except in the form of ruby and sapphire.
Finery forges, smelters, and crucible furnaces can be made out of high-grade
or low-grade refractory bricks. Low-grade bricks can be made out of alunite, bauxite, calcite, chert, chromite, dolomite, kaolinite, obsidian, olivine, periclase, petrified wood, platinum, quartzite, rutile, and sphalerite
*.
*Note:
Sphalerite is currently broken: the sublimation point of crystalline zinc sulfide should be 13,092 Urist; the game data being used -- 12,133 U -- only applies to amorphous (non-crystalline) zinc sulfide. Sphalerite actually converts to wurtzite (another ZnS crystal shape) at 11,836 Urist, which then sublimes at 1991 K == 13,092 U. It will actually melt at that temperature (rather than sublime) at pressures greater than 3 atmospheres.
For the purposes of steeling weapons already made of iron (and because there's no other way to abstract the difference, as far as I know), the kiln can also make
hardening boxes and
steeling boxes, though I'm not married to those names. These boxes are basically large hollow refractory bricks, and can be made out of anything the other bricks can be made out of. The hardening box will just harden the iron, while the steeling box will attempt to turn it into steel, with a chance of failure. The steeling box can also be used on iron bars, while the hardening box can't (it's pure post-processing). In reality, there's no physical difference in a box used for one or the other: it's just a matter of waiting a longer time, which can't really be implemented into DF as such.
Also just for clarification: cast iron and pig iron are the same thing, so there's no reason to implement a totally separate "cast iron" into the game for these purposes. Technically, pig iron is cast iron which has been poured from a blast furnace into packed-sand moulds which have a characteristic shape: a long thin spine with short fat ingots running off of it. Because it resembles a sow suckling piglets, the ingots are called pigs and the metal is called pig iron. That's it. That's the only reason there's a difference in terminology at all.
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Topic: Ironworks 1.1 (Read 12384 times)