Ferro-alloys · Size & tolerance table

Common ferro-alloys: typical content and ISO delivery standards

Standard: ISO 5445 · ISO 5446 · ISO 5447 · ISO 5448 · ISO 5449 · ISO 5450 · ISO 5451 · ISO 5452 · ISO 5453 · ISO 5454

Typical commercial grades as traded, not the grade limits of the standards: each ISO delivery standard defines several grades of its alloy, with its own chemistry limits, size ranges and sampling rules. Contents are in percent by mass; the balance is mainly iron.

Producers often sell to their own typical analysis or a national standard (GB/T in China, IS in India, GOST in Russia), so check which one a quotation refers to.

Bulk ferro-alloys

Alloy	Short name	Main element %	Carbon %	Other main constituent	Mainly used for	ISO standard
High-carbon ferromanganese	HC FeMn	Mn 74–82	6–8	Si below 1.5	Mn alloying and deoxidation, most steels	ISO 5446
Medium-carbon ferromanganese	MC FeMn	Mn 75–85	1–2	Si below 1.5	Mn addition to low-carbon steel	ISO 5446
Low-carbon ferromanganese	LC FeMn	Mn 80–90	below 0.5	Si below 2	Low-carbon and stainless steels	ISO 5446
Silicomanganese	SiMn	Mn 60–70	1.5–2.5	Si 14–20	Deoxidation and Mn in long products and rebar	ISO 5447
Low-carbon silicomanganese	LC SiMn	Mn 58–65	below 0.1	Si 25–30	Refining and low-carbon grades	ISO 5447
Ferrosilicon 75	FeSi 75	Si 72–80	below 0.2	Al 0.5–2	Deoxidation, electrical steel, cast-iron inoculation	ISO 5445
Ferrosilicon 65	FeSi 65	Si 63–68	below 0.2	Al below 2	Deoxidation, cheaper Si units	ISO 5445
High-carbon ferrochrome	HC FeCr	Cr 60–70	6–9	Si below 3	Stainless and alloy steels	ISO 5448
Charge chrome	Charge chrome	Cr 50–55	6–8	Si below 5	Stainless steel (the bulk Cr unit)	ISO 5448
Low-carbon ferrochrome	LC FeCr	Cr 60–75	below 0.15	Si below 1.5	Low-carbon stainless and trimming	ISO 5448
Ferrosilicochrome	FeSiCr	Cr 30–40	below 0.1	Si 35–50	Reducing chromium from slag, low-C alloying	ISO 5449

Noble ferro-alloys

Alloy	Short name	Main element %	Carbon %	Mainly used for	ISO standard
Ferromolybdenum	FeMo 65–70	Mo 60–75	below 0.1	Alloy, tool, stainless and high-strength steels	ISO 5452
Ferrovanadium 80	FeV 80	V 78–85	below 0.5	Micro-alloyed rebar and HSLA steel, tool steel	ISO 5451
Ferrovanadium 50	FeV 50	V 45–60	below 0.5	As FeV 80, a lower-grade unit	ISO 5451
Ferroniobium	FeNb 65	Nb 60–70	below 0.2	Micro-alloyed plate, pipe and automotive steel	ISO 5453
Ferrotitanium 70	FeTi 70	Ti 65–75	below 0.3	Ti-stabilised and IF steels, nitrogen control	ISO 5454
Ferrotitanium 30	FeTi 30	Ti 25–35	below 0.2	Deoxidation and Ti alloying	ISO 5454
Ferrotungsten	FeW 80	W 70–85	below 0.5	High speed and tool steels	ISO 5450
Ferroboron	FeB	B 12–20	below 0.5	Boron steels for hardenability	–

Noble alloys are priced on their contained element — per kg of Mo, V or Nb, or per lb in some markets.
Ferroboron has no ISO delivery standard; it is bought to a producer's or national specification.

Notes

Aluminium (shot, notched bar, wire) and calcium-silicon are also used to deoxidise steel, and ferronickel to add nickel in stainless; they are sold as separate products.
Phosphorus, sulphur and, for special steels, trace elements such as copper, tin and titanium are limited in each grade; specify the limits your steel needs.