|This article is about an older version of DF.|
To smelt steel, you will need iron ore, flux stone, and fuel. Flux is used to remove impurities including carbon during the smelting process, while fuel (coke or charcoal) removes oxygen and puts back in a small amount of carbon. The end result is steel: iron with just the right amount of carbon in it. The three ores of iron (hematite, magnetite, and limonite) can only be found in sedimentary layers, with the exception of hematite, which can occasionally be found in igneous extrusive layers. Furthermore, four of the five flux stones (calcite, chalk, dolomite, and limestone) are found only in sedimentary layers, as well as both coal ores (bituminous coal and lignite) for making coke fuel.
If you have no sedimentary layers at your fortress site, your only hope to make steel is with:
- hematite from igneous extrusive layers, or iron ore imported from trade caravans
- melting iron items brought by siegers and caravans
- marble from metamorphic layers, or imported flux
- coke from imported bituminous coal, or charcoal from wood
Note that bituminous coal, like most stones, costs only 3☼ at embark or from caravans. With a cunning enough starting build, it is possible to embark with enough for several hundred units of coke. This is only possible if your parent civilization has access to coal; otherwise it will not be available at all, meaning you will have to cut down a tree and burn it to make charcoal for every bar of steel, even with access to magma smelters.
Steel production is fairly complex compared to the creation of other alloys. Important note: in steelmaking, coke or charcoal is also used as an ingredient, apart from its use as fuel. A conventional (non-magma) smelter will require an additional unit of fuel in each reaction.
The first step is to create pig iron:
- 1 bar of pig iron
The second step combines the pig iron with plain iron to produce steel:
- 1 bar of iron
- 1 bar of pig iron
- 1 flux stone
- 1 unit of fuel (as a source of carbon)
- 1 unit of fuel, or magma (to heat the forge)
- 2 bars of steel
The overall reaction consumes 2 bars of iron, 2 units of flux, and 2 units of fuel as ingredients (plus an extra 2 fuel at a conventional smelter for heating). This produces 2 bars of steel.
Remember that smelting iron ore also requires 1 unit of fuel at a conventional smelter, producing 4 bars of iron, which translates to half a unit of additional fuel used in the recipe above (although you will need a full unit up front.)
[INORGANIC:STEEL] [USE_MATERIAL_TEMPLATE:METAL_TEMPLATE] [STATE_NAME_ADJ:ALL_SOLID:steel] [STATE_NAME_ADJ:LIQUID:molten steel] [STATE_NAME_ADJ:GAS:boiling steel] [DISPLAY_COLOR:0:7:1] [BUILD_COLOR:0:7:1] [MATERIAL_VALUE:30] [SPEC_HEAT:500] [MELTING_POINT:12718] [BOILING_POINT:14968] [ITEMS_WEAPON][ITEMS_WEAPON_RANGED][ITEMS_AMMO][ITEMS_DIGGER][ITEMS_ARMOR][ITEMS_ANVIL] [SOLID_DENSITY:7850] [LIQUID_DENSITY:6980] [MOLAR_MASS:55845] [IMPACT_YIELD:1505000] [IMPACT_FRACTURE:2520000] [IMPACT_STRAIN_AT_YIELD:940] [COMPRESSIVE_YIELD:1505000] [COMPRESSIVE_FRACTURE:2520000] [COMPRESSIVE_STRAIN_AT_YIELD:940] 160 [TENSILE_YIELD:430000] [TENSILE_FRACTURE:720000] [TENSILE_STRAIN_AT_YIELD:225] 200 [TORSION_YIELD:430000] [TORSION_FRACTURE:720000] [TORSION_STRAIN_AT_YIELD:215] [SHEAR_YIELD:430000] [SHEAR_FRACTURE:720000] [SHEAR_STRAIN_AT_YIELD:215] no data, used 200 [BENDING_YIELD:430000] [BENDING_FRACTURE:720000] [BENDING_STRAIN_AT_YIELD:215] [MAX_EDGE:10000] [ITEMS_HARD] [ITEMS_METAL] [ITEMS_BARRED] [ITEMS_SCALED] [STATE_COLOR:ALL_SOLID:GRAY]