Ferroaluminium (FeAl) for steel deoxidation and aluminium additions · FeAl 40 and FeAl 50 aluminium bands, C, S, P, Si, Mn and Cu limits, ingot and granule size classes, density 5.5–6.1 g/cm³, lump and powder forms
Ferroaluminium is an iron–aluminium alloy made by fusion and added to liquid steel to remove oxygen and to add aluminium. Because pure aluminium stays near the bath surface and reacts with air and slag, the iron carrier is there to make the addition heavy enough to sink. Settle three things before asking for prices: which aluminium band you need (for example 35–40% or 45–50%), the carbon, silicon, sulphur and phosphorus ceilings your steel grade can tolerate, and the lump, granule or powder size that suits your ladle or feeding practice.
Ferroaluminium (FeAl, iron–aluminium alloy) supplied as lumps, ingots, crushed granules or powder for deoxidation and aluminium alloying of steel and iron, including grades sold as ferro-aluminium master alloy. Pure aluminium shot, notched bar and wire, aluminium cored wire, ferrosilicon, ferromanganese, ferrotitanium and Fe-Al intermetallic coatings are outside this page except where compared.
CNFX editorial research · Sources checked October 11, 2026 · 4 sources
IS 12908:1990 treats ferroaluminium as a master alloy of iron and aluminium obtained by fusion, with at least 35.0% and at most 50.0% aluminium by mass. It sets two grades: FeAl 40 with 35.0–40.0% Al and maxima of 0.10% C, 0.03% S, 0.03% P, 0.50% Si, 0.50% Mn and 0.30% Cu; and FeAl 50 with 45.0–50.0% Al and maxima of 0.50% C, 0.03% S, 0.03% P, 0.60% Si, 0.60% Mn and 0.50% Cu. The standard says its Table 1 "shows only the main constituents elements and usual impurities"; tighter aluminium ranges or extra element limits have to be agreed between buyer and maker. On request, the maker supplies a chemical analysis certificate for each melt, and an off-specification melt may not be blended into another. [1]
Commercial sheets do not always sit inside these two bands. Cometal's lump ferroaluminium sheet gives 30–35% Al with Si 1% max, S 0.001% max, Mn 0.5% max, C 0.2% max, Cu 0.2% max, P 0.009% max and iron as balance — lower aluminium than FeAl 40, a higher silicon and carbon ceiling, but far tighter sulphur and phosphorus. [2] Quote requests should therefore name every element limit rather than a grade label alone.
Editorial calculation: iron is the balance in both IS grades, so iron plus residuals is 100 − Al, i.e. about 60–65% in FeAl 40 and 50–55% in FeAl 50; Cometal's 30–35% Al lump implies roughly 65–70% iron plus residuals. [1][2]
Send the supplier: the aluminium band (minimum and maximum), maxima for C, S, P, Si, Mn and Cu, whether the limits apply to the lot average or to each lump, the lot method (tapped, graded or blended), the size class, the packing and mass per container, and whether a per-melt analysis certificate is required.
02
Plan the ladle addition: density, size and form
The IS 12908 foreword gives the purpose: better control of deoxidation when making semi-killed and killed steels, plus aluminium additions in iron and steel making. [1] US patent 4,921,533 explains the mechanism behind adding aluminium as an iron alloy. Aluminium on its own (about 2.7 g/cm³) stays near the bath surface and reacts with the furnace atmosphere and slag, whereas the denser iron alloy penetrates the bath and reacts less rapidly. The patent puts slag density at about 2.5 to 3.5 or 4 g/cm³, says an addition must be well above 4 to pass through it, and notes that a 65% Al alloy has not been used commercially because its density, below 4 g/cm³, does not carry it deep enough into the bath. It also records two handling drawbacks of the nominal 35–40% Al commercial alloy: it can decrepitate and crumble in storage, and pieces can break up from thermal shock on entering the bath, which lowers deoxidation efficiency. [4]
IS 12908 requires a density of 5.5 to 6.1 g/cc. Its size classes are a 250 mm ingot (class 1) and crushed granules of 2–20 mm (class 2), 2–50 mm (class 3) and 2–100 mm (class 4), each granule class allowing at most 10% oversize and no undersize at delivery. [1] Cometal ships its lump grade at 5 x 50 mm in 500 kg drums, with a certificate of analysis on each delivery. [2]
Powder is a separate form. Mepco's FEAL 50 powder sheet lists 47–53% Al and 47–53% Fe, metallic impurity maxima of 0.50% Cu, 1.00% Si, 1.00% Mn, 0.05% Mg, 0.50% Zn and 0.10% Ca, and a sieve analysis (ASTM B-214) of at most 1.0% above 150 µm and at least 45.0% below 45 µm; its listed uses include deoxidiser, alloy addition, foundry flux and welding electrodes. [3]
Ask for the alloy's measured density and the size distribution at delivery, and state how the alloy will be added (ladle drop, furnace, injection or powder blend) so the supplier can match lump size or powder grading.
03
Lining up ferroaluminium offers against IS 12908
When comparing offers, put each quotation's aluminium band, every impurity ceiling, size class, density and packing side by side against IS 12908 or your own specification, and ask for a recent per-melt analysis certificate with the quotation.
04
Read the composition line by line
A functional reading of the published limits; it is not one maker's formulation.
Al band, density and lump or powder grading on the purchase order
The particle-size row spans ingot, crushed granules, lumps and fine powder across the sources, so fix the form before comparing prices; melting point, moisture and bulk density are not stated in any reviewed source and have to come from the supplier.
Field
What it means and published values
Ask the supplier for
Aluminum Content
35.0–40.0% or 45.0–50.0% (IS grades); 30–35% lump; 47–53% powder. [1][2][3]
Explore company information and manufacturing capabilities, then discuss the scope of your project with a relevant supplier.
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Compiled and source-reviewed by the CNFX editorial team.
Each manufacturer above links to the page on that company's own website where the product is listed, with the date we checked it. How we source and review
· Page last updated 13 October 2026
Buyer questions
What grades of ferroaluminium does IS 12908 define?
Two: FeAl 40 with 35.0–40.0% Al and 0.10% C max, and FeAl 50 with 45.0–50.0% Al and 0.50% C max; both cap S and P at 0.03%. [1]
Why add aluminium as ferroaluminium instead of pure aluminium?
US patent 4,921,533 says pure aluminium is light enough to stay near the surface and react with air and slag, while the iron alloy is denser and penetrates the bath. [4]
What sizes is ferroaluminium sold in?
IS 12908 lists a 250 mm ingot and 2–20, 2–50 and 2–100 mm granules; Cometal lists 5 x 50 mm lumps and Mepco a powder at least 45.0% finer than 45 µm. [1][2][3]
Sources and what still needs a direct check
Sources checked 2026-10-11. The sources are an Indian national standard, two supplier data sheets (lump and powder) and a US patent on ferroaluminium deoxidisers.
