More manual

Added sections on the technic-specific kinds of item processing, and on
generic metal mechanics, and the specific trickery around iron (merging
in notes_on_iron).
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Zefram 2014-08-08 23:22:36 +01:00
parent ddb522d4cc
commit eed803349c
2 changed files with 263 additions and 69 deletions

264
manual.md

@ -160,12 +160,274 @@ elevation -150 downwards. It is much harder to dig than standard stone,
so impedes mining when it is encountered. It has mainly decorative use, so impedes mining when it is encountered. It has mainly decorative use,
but also appears in a couple of machine recipes. but also appears in a couple of machine recipes.
alloying
--------
In technic, alloying is a way of combining items to create other items,
distinct from standard crafting. Alloying always uses inputs of exactly
two distinct types, and produces a single output. Like cooking, which
takes a single input, it is performed using a powered machine, known
generically as an "alloy furnace". An alloy furnace always has two
input slots, and it doesn't matter which way round the two ingredients
are placed in the slots. Many alloying recipes require one or both
slots to contain a stack of more than one of the ingredient item: the
quantity required of each ingredient is part of the recipe.
As with the furnaces used for cooking, there are multiple kinds of alloy
furnace, powered in different ways. The most-used alloy furnaces are
electrically powered. There is also an alloy furnace that is powered
by directly burning fuel, just like the basic cooking furnace. Building
almost any electrical machine, including the electrically-powered alloy
furnaces, requires a machine casing component, one ingredient of which
is brass, an alloy. It is therefore necessary to use the fuel-fired
alloy furnace in the early part of the game, on the way to building
electrical machinery.
Alloying recipes are mainly concerned with metals. These recipes
combine a base metal with some other element, most often another metal,
to produce a new metal. This is discussed in the section on metal.
There are also a few alloying recipes in which the base ingredient is
non-metallic, such as the recipe for the silicon wafer.
grinding, extracting, and compressing
-------------------------------------
Grinding, extracting, and compressing are three distinct, but very
similar, ways of converting one item into another. They are all quite
similar to the cooking found in the basic Minetest game. Each uses
an input consisting of a single item type, and produces a single
output. They are all performed using powered machines, respectively
known generically as a "grinder", "extractor", and "compressor".
Some compressing recipes require the input to be a stack of more than
one of the input item: the quantity required is part of the recipe.
Grinding and extracting recipes never require such a stacked input.
There are multiple kinds of grinder, extractor, and compressor. Unlike
cooking furnaces and alloy furnaces, there are none that directly burn
fuel; they are all electrically powered.
Grinding recipes always produce some kind of dust, loosely speaking,
as output. The most important grinding recipes are concerned with metals:
every metal lump or ingot can be ground into metal dust. Coal can also
be ground into dust, and burning the dust as fuel produces much more
energy than burning the original coal lump. There are a few other
grinding recipes that make block types from the basic Minetest game
more interconvertible: standard stone can be ground to standard sand,
desert stone to desert sand, cobblestone to gravel, and gravel to dirt.
Extracting is a miscellaneous category, used for a small group
of processes that just don't fit nicely anywhere else. (Its name is
notably vaguer than those of the other kinds of processing.) It is used
for recipes that produce dye, mainly from flowers. (However, for those
recipes using flowers, the basic Minetest game provides parallel crafting
recipes that are easier to use and produce more dye, and those recipes
are not suppressed by technic.) Its main use is to generate rubber from
raw latex, which it does three times as efficiently as merely cooking
the latex. Extracting was also formerly used for uranium enrichment for
use as nuclear fuel, but this use has been superseded by a new enrichment
system using the centrifuge.
Compressing recipes are mainly used to produce a few relatively advanced
artificial item types, such as the copper and carbon plates used in
advanced machine recipes. There are also a couple of compressing recipes
making natural block types more interconvertible.
centrifuging
------------
Centrifuging is another way of using a machine to convert items.
Centrifuging takes an input of a single item type, and produces outputs
of two distinct types. The input may be required to be a stack of
more than one of the input item: the quantity required is part of
the recipe. Centrifuging is only performed by a single machine type,
the MV (electrically-powered) centrifuge.
Generally, centrifuging separates the input item into constituent
substances, but it can only work when the input is reasonably fluid,
and in marginal cases it is quite destructive to item structure.
(In real life, centrifuges require their input to be mainly fluid, that
is either liquid or gas. Few items in the game are described as liquid
or gas, so the concept of the centrifuge is stretched a bit to apply to
finely-divided solids.)
The main use of centrifuging is in uranium enrichment, where it
separates the isotopes of uranium dust that otherwise appears uniform.
Enrichment is a necessary process before uranium can be used as nuclear
fuel, and the radioactivity of uranium blocks is also affected by its
isotopic composition.
A secondary use of centrifuging is to separate the components of
metal alloys. This can only be done using the dust form of the alloy.
It recovers both components of binary metal/metal alloys. It can't
recover the carbon from steel or cast iron.
metal
-----
Many of the substances important in technic are metals, and there is
a common pattern in how metals are handled. Generally, each metal can
exist in five forms: ore, lump, dust, ingot, and block. With a couple of
tricky exceptions in mods outside technic, metals are only *used* in dust,
ingot, and block forms. Metals can be readily converted between these
three forms, but can't be converted from them back to ore or lump forms.
As in the basic Minetest game, a "lump" of metal is acquired directly by
digging ore, and will then be processed into some other form for use.
A lump is thus more akin to ore than to refined metal. (In real life,
metal ore rarely yields lumps ("nuggets") of pure metal directly.
More often the desired metal is chemically bound into the rock as an
oxide or some other compound, and the ore must be chemically processed
to yield pure metal.)
Not all metals occur directly as ore. Generally, elemental metals (those
consisting of a single chemical element) occur as ore, and alloys (those
consisting of a mixture of multiple elements) do not. In fact, if the
fictional mithril is taken to be elemental, this pattern is currently
followed perfectly. (It is not clear in the Middle-Earth setting whether
mithril is elemental or an alloy.) This might change in the future:
in real life some alloys do occur as ore, and some elemental metals
rarely occur naturally outside such alloys. Metals that do not occur
as ore also lack the "lump" form.
The basic Minetest game offers a single way to refine metals: cook a lump
in a furnace to produce an ingot. With technic this refinement method
still exists, but is rarely used outside the early part of the game,
because technic offers a more efficient method once some machines have
been built. The grinder, available only in electrically-powered forms,
can grind a metal lump into two piles of metal dust. Each dust pile
can then be cooked into an ingot, yielding two ingots from one lump.
This doubling of material value means that you should only cook a lump
directly when you have no choice, mainly early in the game when you
haven't yet built a grinder.
An ingot can also be ground back to (one pile of) dust. Thus it is always
possible to convert metal between ingot and dust forms, at the expense
of some energy consumption. Nine ingots of a metal can be crafted into
a block, which can be used for building. The block can also be crafted
back to nine ingots. Thus it is possible to freely convert metal between
ingot and block forms, which is convenient to store the metal compactly.
Every metal has dust, ingot, and block forms.
Alloying recipes in which a metal is the base ingredient, to produce a
metal alloy, always come in two forms, using the metal either as dust
or as an ingot. If the secondary ingredient is also a metal, it must
be supplied in the same form as the base ingredient. The output alloy
is also returned in the same form. For example, brass can be produced
by alloying two copper ingots with one zinc ingot to make three brass
ingots, or by alloying two piles of copper dust with one pile of zinc
dust to make three piles of brass dust. The two ways of alloying produce
equivalent results.
iron and its alloys
-------------------
Iron forms several important alloys. In real-life history, iron was the
second metal to be used as the base component of deliberately-constructed
alloys (the first was copper), and it was the first metal whose working
required processes of any metallurgical sophistication. The game
mechanics around iron broadly imitate the historical progression of
processes around it, rather than the less-varied modern processes.
The two-component alloying system of iron with carbon is of huge
importance, both in the game and in real life. The basic Minetest game
doesn't distinguish between these pure iron and these alloys at all,
but technic introduces a distinction based on the carbon content, and
renames some items of the basic game accordingly.
The iron/carbon spectrum is represented in the game by three metal
substances: wrought iron, carbon steel, and cast iron. Wrought iron
has low carbon content (less than 0.25%), resists shattering, and
is easily welded, but is relatively soft and susceptible to rusting.
In real-life history it was used for rails, gates, chains, wire, pipes,
fasteners, and other purposes. Cast iron has high carbon content
(2.1% to 4%), is especially hard, and resists corrosion, but is
relatively brittle, and difficult to work. Historically it was used
to build large structures such as bridges, and for cannons, cookware,
and engine cylinders. Carbon steel has medium carbon content (0.25%
to 2.1%), and intermediate properties: moderately hard and also tough,
somewhat resistant to corrosion. In real life it is now used for most
of the purposes previously satisfied by wrought iron and many of those
of cast iron, but has historically been especially important for its
use in swords, armour, skyscrapers, large bridges, and machines.
In real-life history, the first form of iron to be refined was
wrought iron, which is nearly pure iron, having low carbon content.
It was produced from ore by a low-temperature furnace process (the
"bloomery") in which the ore/iron remains solid and impurities (slag)
are progressively removed by hammering ("working", hence "wrought").
This began in the middle East, around 1800 BCE.
Historically, the next forms of iron to be refined were those of high
carbon content. This was the result of the development of a more
sophisticated kind of furnace, the blast furnace, capable of reaching
higher temperatures. The real advantage of the blast furnace is that it
melts the metal, allowing it to be cast straight into a shape supplied by
a mould, rather than having to be gradually beaten into the desired shape.
A side effect of the blast furnace is that carbon from the furnace's fuel
is unavoidably incorporated into the metal. Normally iron is processed
twice through the blast furnace: once producing "pig iron", which has
very high carbon content and lots of impurities but lower melting point,
casting it into rough ingots, then remelting the pig iron and casting it
into the final moulds. The result is called "cast iron". Pig iron was
first produced in China around 1200 BCE, and cast iron later in the 5th
century BCE. Incidentally, the Chinese did not have the bloomery process,
so this was their first iron refining process, and, unlike the rest of
the world, their first wrought iron was made from pig iron rather than
directly from ore.
Carbon steel, with intermediate carbon content, was developed much later,
in Europe in the 17th century CE. It required a more sophisticated
process, because the blast furnace made it extremely difficult to achieve
a controlled carbon content. Tweaks of the blast furnace would sometimes
produce an intermediate carbon content by luck, but the first processes to
reliably produce steel were based on removing almost all the carbon from
pig iron and then explicitly mixing a controlled amount of carbon back in.
In the game, the bloomery process is represented by ordinary cooking
or grinding of an iron lump. The lump represents unprocessed ore,
and is identified only as "iron", not specifically as wrought iron.
This standard refining process produces dust or an ingot which is
specifically identified as wrought iron. Thus the standard refining
process produces the (nearly) pure metal.
Cast iron is trickier. You might expect from the real-life notes above
that cooking an iron lump (representing ore) would produce pig iron that
can then be cooked again to produce cast iron. This is kind of the case,
but not exactly, because as already noted cooking an iron lump produces
wrought iron. The game doesn't distinguish between low-temperature
and high-temperature cooking processes: the same furnace is used not
just to cast all kinds of metal but also to cook food. So there is no
distinction between cooking processes to produce distinct wrought iron
and pig iron. But repeated cooking *is* available as a game mechanic,
and is indeed used to produce cast iron: re-cooking a wrought iron ingot
produces a cast iron ingot. So pig iron isn't represented in the game as
a distinct item; instead wrought iron stands in for pig iron in addition
to its realistic uses as wrought iron.
Carbon steel is produced by a more regular in-game process: alloying
wrought iron with coal dust (which is essentially carbon). This bears
a fair resemblance to the historical development of carbon steel.
This alloying recipe is relatively time-consuming for the amount of
material processed, when compared against other alloying recipes, and
carbon steel is heavily used, so it is wise to alloy it in advance,
when you're not waiting for it.
There are additional recipes that permit all three of these types of iron
to be converted into each other. Alloying carbon steel again with coal
dust produces cast iron, with its higher carbon content. Cooking carbon
steel or cast iron produces wrought iron, in an abbreviated form of the
bloomery process.
There's one more iron alloy in the game: stainless steel. It is managed
in a completely regular manner, created by alloying carbon steel with
chromium.
subjects missing from this manual subjects missing from this manual
--------------------------------- ---------------------------------
This manual needs to be extended with sections on: This manual needs to be extended with sections on:
* alloying * rubber
* electrical networks * electrical networks
* the powered machine types * the powered machine types
* how machines interact with tubes * how machines interact with tubes

@ -1,68 +0,0 @@
Notes on iron and steel
=======================
Alloying iron with carbon is of huge importance, but in some processes
the alloying is an implicit side effect rather than the product of
explicit mixing, so it is a complex area. In the real world, there is
a huge variety of kinds of iron and steel, differing in the proportion
of carbon included and in other elements added to the mix.
The Minetest default mod doesn't distinguish between types of iron and
steel at all. This mod introduces multiple types in order to get a bit
of complexity and flavour.
Leaving aside explicit addition of other elements, the iron/carbon
spectrum is here represented by three substances: wrought iron,
carbon steel, and cast iron. Wrought iron has low carbon content
(less than 0.25%), resists shattering, and is easily welded, but is
relatively soft and susceptible to rusting. It was used for rails,
gates, chains, wire, pipes, fasteners, and other purposes. Cast iron
has high carbon content (2.1% to 4%), is especially hard, and resists
corrosion, but is relatively brittle, and difficult to work. It was used
to build large structures such as bridges, and for cannons, cookware,
and engine cylinders. Carbon steel has medium carbon content (0.25%
to 2.1%), and intermediate properties: moderately hard and also tough,
somewhat resistant to corrosion. It is now used for most of the purposes
previously satisfied by wrought iron and many of those of cast iron,
but has historically been especially important for its use in swords,
armour, skyscrapers, large bridges, and machines.
Historically, the first form of iron to be refined was wrought iron,
produced from ore by a low-temperature furnace process in which the
ore/iron remains solid and impurities (slag) are progressively removed.
Cast iron, by contrast, was produced somewhat later by a high-temperature
process in a blast furnace, in which the metal is melted, and carbon is
unavoidably incorporated from the furnace's fuel. (In fact, it's done
in two stages, first producing pig iron from ore, and then remelting the
pig iron to cast as cast iron.) Carbon steel requires a more advanced
process, in which molten pig iron is processed to remove the carbon,
and then a controlled amount of carbon is explicitly mixed back in.
Other processes are possible to refine iron ore and to adjust its
carbon content.
Unfortunately, Minetest doesn't let us readily distinguish between
low-temperature and high-temperature processes: in the default game, the
same furnace is used both to cook food (low temperature) and to cast metal
ingots (varying high temperatures). So we can't sensibly have wrought
iron and cast iron produced by different types of furnace. Nor can
furnace recipes discriminate by which kind of fuel is used (and thus
by the availability of carbon). The alloy furnace allows for explicit
alloying, which appropriately represents how carbon steel is made, but
is not sensible for the other two, and is a relatively advanced process.
About the only option to make a second iron-processing furnace process
readily available is to cook multiple times; happily, this bears a slight
resemblance to the real process with pig iron as an intermediate product.
The default mod's refined iron, which it calls "steel", is identified
with this mod's wrought iron. Cooking an iron lump (representing ore)
initially produces wrought iron; the cooking process here represents a
low-temperature bloomery process. Cooking wrought iron then produces
cast iron; this time the cooking process represents a blast furnace.
Alloy cooking wrought iron with coal dust (carbon) produces carbon steel;
this represents the explicit mixing stage of carbon steel production.
Additionally, alloy cooking carbon steel with coal dust produces cast
iron, which is logical but not very useful. Furthermore, to make it
possible to turn any of the forms of iron into any other, cooking carbon
steel or cast iron produces wrought iron, in an abbreviated form of the
bloomery process. As usual for metals, the same cooking and alloying
processes can be performed in parallel forms on ingots or dust.