Steel Glossary

A

AISC: American Institute of Steel Construction — structural steel design and fabrication standards in the US.
AISI: American Iron and Steel Institute; its numbering (1018, 4140, 304, 316) is still the common name for many grades.
Alloy steel: Steel with deliberate additions (chromium, molybdenum, nickel, vanadium, boron…) above the limits for non-alloy steel.
Aluzinc / Galvalume: Sheet coated with an aluminium-zinc alloy (about 55% Al), longer-lasting than plain zinc in many atmospheres.
Annealing: Heating and slow cooling to soften steel, relieve stress or refine its structure.
API: American Petroleum Institute — standards for oil and gas equipment, e.g. API 5L line pipe and API 5CT casing and tubing.
Apparent steel use: Production plus imports minus exports — the steel a market consumes.
ASME: American Society of Mechanical Engineers — the Boiler and Pressure Vessel Code and the B16 and B36 pipe and fitting standards.
ASTM: ASTM International — the most widely used US materials standards (A36, A53, A106, A240, A615…).
AWS: American Welding Society — welding consumable classifications and structural welding codes.

B

Bar mill: A rolling mill that makes bars and rebar from billets.
BF-BOF: Blast furnace and basic oxygen furnace — the integrated route from iron ore and coke to steel.
Billet: Semi-finished steel of square or near-square section, rolled into bars, rebar, wire rod and light sections.
Black pipe: Uncoated steel pipe, as opposed to galvanised.
Bloom: Semi-finished steel larger than a billet, rolled into heavy sections and rails.
BS: British Standard, issued by BSI. Many have been replaced by EN standards (BS EN …).

C

CE (carbon equivalent): A number worked out from the chemistry that indicates weldability. See the steel calculators.
CEN: European Committee for Standardization, which issues EN standards.
CFR / CIF: Incoterms® rules in which the seller pays freight to the destination port (CIF also insurance); risk passes at loading.
Charpy test: An impact test that measures the energy a notched specimen absorbs when broken, at a set temperature — a measure of toughness.
Coil: Flat steel or wire rod wound for transport. Flat coil is sold by width, thickness and coil weight.
Cold rolled (CR): Rolled at room temperature after pickling: thinner, smoother and more precise than hot rolled.
Continuous casting: Casting liquid steel directly into billets, blooms or slabs instead of ingots.
CRC: Cold-rolled coil.
Cut to length (CTL): Sheet or plate cut from coil to a set length.

D

DIN: Deutsches Institut für Normung — German standards body; many DIN steel standards are now EN.
DRI / HBI: Direct-reduced iron, made by reducing iron ore with gas below melting point; HBI is DRI pressed into briquettes for shipping.

E

EAF: Electric arc furnace — melts scrap and DRI to make steel. Almost all Middle East steel is made this way.
EN: European Standard (Europäische Norm), issued by CEN and adopted by every member country.
EN 10204: The European standard for inspection documents: 2.1, 2.2, 3.1 and 3.2. See mill test certificates.
ERW: Electric resistance welded (pipe), formed from strip and welded along a straight seam.

F

FOB: Free on board — Incoterms® rule: the seller loads the goods on the buyer's vessel; risk passes on board.

G

Galvanised (GI, HDG): Coated with zinc, usually by dipping in molten zinc (hot-dip galvanising).
GB: Guobiao — Chinese national standard.
GOST: Russian and CIS state standard.
Grade: The name of a steel within a standard, fixing its chemistry and properties (S355J2, ASTM A36, SS400).
GSO: GCC Standardization Organization — standards adopted across the six GCC states.

H

Heat (cast) number: The number of one melt of steel, marked on the product and on its certificate — the link that makes traceability possible.
HMS: Heavy melting scrap (HMS 1 & 2) — the most traded grade of ferrous scrap.
Hot rolled (HR): Rolled above the recrystallisation temperature: the cheapest flat and long products, with a scaled surface.
HRC: Hot-rolled coil — or, in testing, Rockwell C hardness. The context decides.
HS code: Harmonized System customs code. Steel is Chapter 72, articles of steel Chapter 73.

I

IIW: International Institute of Welding; its carbon equivalent formula is the most widely used.
Incoterms®: The ICC's rules splitting delivery tasks, costs and risk between seller and buyer.
Ingot: Steel cast in a mould as a block, now mostly replaced by continuous casting.
ISO: International Organization for Standardization.

J

JIS: Japanese Industrial Standard (SS400, SPCC, SUS304).

L

L/C (letter of credit): A bank's undertaking to pay the seller when it presents documents that match the credit.
Line pipe: Pipe for oil, gas and water pipelines, usually to API 5L / ISO 3183.
LSAW / SSAW: Large-diameter pipe welded by submerged arc along a straight (L) or spiral (S) seam.

M

MOQ: Minimum order quantity.
MS: Mild steel — low-carbon structural steel.
MTC: Mill test certificate — usually an EN 10204 3.1 inspection certificate.

N

NACE: Now AMPP — its MR0175 / ISO 15156 sets material limits for sour (H₂S) service.
NDT: Non-destructive testing — ultrasonic, radiographic, magnetic-particle and dye-penetrant tests.
Normalising: Heating above the transformation range and cooling in air to give a fine, even structure (delivery condition +N).

O

OCTG: Oil country tubular goods — casing, tubing and drill pipe.

P

P&O: Pickled and oiled — hot-rolled steel with the scale removed in acid and oiled against rust.
Pcm: A carbon equivalent for low-carbon steels (Ito-Bessyo formula).
Pickling: Removing mill scale in acid before cold rolling or coating.
PPGI / PPGL: Pre-painted galvanised / galvalume sheet (colour-coated).
PREN: Pitting resistance equivalent number — ranks stainless steels for chloride resistance.

Q

Q&T: Quenched and tempered — hardened by quenching, then tempered for toughness.
QA / QC: Quality assurance / quality control.

R

Rebar: Ribbed reinforcing bar for concrete.
Rockwell, Brinell, Vickers: The three common hardness tests (HRC/HRB, HB, HV). See the unit converter for approximate conversions.

S

SASO: Saudi Standards, Metrology and Quality Organization.
SAW: Submerged arc welding — the process used for heavy plate and large pipe.
Schedule (SCH): Pipe wall thickness designation (SCH 40, SCH 80) under ASME B36.10M and B36.19M.
Seamless pipe: Pipe made by piercing a solid billet, with no weld seam.
Section: A rolled shape — angle, channel, beam, column.
Slab: Semi-finished steel of wide rectangular section, rolled into plate and coil.
Slitting: Cutting a coil lengthways into narrower strips.
SS: Stainless steel — or, in JIS grade names such as SS400, general structural steel.
Stainless steel: Steel with at least about 10.5% chromium, which forms a protective oxide layer.
Stockist: A distributor that holds steel in stock and sells it in smaller quantities, often cut to size.

T

Tinplate: Thin cold-rolled steel coated with tin, mainly for cans.
TMCP: Thermo-mechanically controlled processing — rolling and cooling controlled to give strength and toughness with lean chemistry (delivery condition +M).
Tolerance: The permitted deviation from a nominal dimension, set by the product standard.

W

Wire rod: Hot-rolled round in coils, usually 5.5–16 mm, drawn into wire or used as mesh and rebar.

Y

Yield strength: The stress at which steel starts to deform permanently; the number in most structural grade names (S355 = 355 MPa minimum).

Z

Z-quality: Plate tested for through-thickness ductility (Z15, Z25, Z35) to resist lamellar tearing.
ZnAl / ZM: Zinc-aluminium(-magnesium) metallic coatings for sheet.

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