Resources
Steel Glossary
40 verified, source-cited terms — flat-rolled steel terminology for buyers, engineers, and shop-floor teams. Compiled by Metal Master Technical Team from ASTM, AISC, Nucor, U.S. Steel, and industry technical sources.
40 of 40 terms
Substrates & Grades
Aluminum-Killed, Drawing Quality (AKDQ)
Steel deoxidized with aluminum for uniform, formable performance.
- A type of steel to which aluminum has been added during the deoxidation process to remove oxygen. This results in a more uniform and consistent material that performs reliably in high-volume stamping, forming, and welding operations.
Source(s): alro.com
ASTM A1008 / A1008M
Standard for cold-rolled carbon, structural, and HSLA steel sheet.
- The standard specification from ASTM International for cold-rolled carbon, structural, and high-strength low-alloy (HSLA) steel sheets, in coils and cut lengths. It includes formability designations such as DS, DDS, and EDDS.
Source(s): store.astm.org, steelwarehouse.com
See also: Cold-Rolled Steel (CR), Drawing Steel (DS), Deep Drawing Steel (DDS)
ASTM A1011 / A1011M
Standard for hot-rolled carbon, structural, HSLA, and ultra-high-strength sheet.
- The standard specification from ASTM International for hot-rolled carbon, structural, high-strength low-alloy (HSLA), and ultra-high strength steel sheet and strip.
Source(s): store.astm.org, ssab.com, steelwarehouse.com
See also: Hot-Rolled Steel (HR), Structural Steel (SS)
Bake Hardenable Steel (BHS)
Formable when stamped, stronger after paint bake.
- A type of steel, defined within standards like ASTM A1008, engineered to remain relatively soft and formable during stamping operations but to increase in strength and hardness when subjected to the heat of a paint-baking cycle.
Source(s): store.astm.org
Cold-Rolled Steel (CR)
Steel reduced near room temperature for tight tolerances and smooth surface.
- Steel that has been processed at or near room temperature by passing it through rollers to reduce its thickness. This process imparts a smoother surface finish, tighter dimensional tolerances, and increased strength compared to hot-rolled steel.
Source(s): aisi.org, harvardsteelsales.com, benedict-miller.com
See also: Hot-Rolled Steel (HR), ASTM A1008 / A1008M
Commercial Steel (CS)
General-purpose flat-rolled steel for moderate forming.
- A designation within ASTM standards (e.g., A1008, A1011) for steel intended for general-purpose applications. It is typically furnished to meet chemical composition requirements, while mechanical properties are secondary and not guaranteed. CS Type B is a common grade.
Source(s): usmadesupply.com, store.astm.org, baobingroup.com
Drawing Steel (DS)
Improved ductility for moderate drawing and forming.
- A designation within ASTM standards (e.g., A1008, A1011) for steel with improved ductility compared to Commercial Steel (CS). It is intended for applications involving moderate drawing or forming operations.
Source(s): store.astm.org, usmadesupply.com
Deep Drawing Steel (DDS)
Cold-rolled grade engineered for severe drawing operations.
- A designation within ASTM A1008 for cold-rolled steel specifically engineered for severe forming operations (deep drawing) where the material must undergo significant plastic deformation without fracturing. It offers higher ductility than Drawing Steel (DS).
Source(s): store.astm.org, alro.com
Extra Deep Drawing Steel (EDDS)
Highest formability tier for cold-rolled sheet under ASTM A1008.
- The highest tier of formability for cold-rolled steel under ASTM A1008. EDDS is designed for the most severe and complex deep-drawn parts, where maximum ductility and resistance to tearing are required.
Source(s): store.astm.org, alro.com
Full Hard
Cold-rolled to final gauge with no anneal — high strength, low ductility.
- A temper designation for cold-rolled steel that has been reduced to its final gauge but has not been annealed. This results in a material with high hardness and tensile strength but very low ductility, making it unsuitable for forming.
Source(s): harvardsteelsales.com, miamivalleysteel.com
High-Strength Low-Alloy Steel (HSLAS)
Micro-alloyed grades with higher strength and corrosion resistance.
- A category of steels, in standards like ASTM A1011 and A1008, engineered to provide better mechanical properties and greater resistance to atmospheric corrosion than conventional carbon steels. They achieve this with small additions of alloying elements like niobium, vanadium, and titanium.
Source(s): ssab.com, store.astm.org
Hot-Rolled Steel (HR)
Steel rolled and processed at high temperatures (typically above 1,700°F).
- Steel that is rolled and processed at high temperatures (typically above 1,700°F). It is characterized by a rougher surface finish (mill scale) and looser dimensional tolerances compared to cold-rolled steel but is generally more economical.
Source(s): harvardsteelsales.com, usmadesupply.com
See also: Cold-Rolled Steel (CR), Mill Scale, Hot Rolled Pickled and Oiled (HRPO)
Hot Rolled Pickled and Oiled (HRPO)
Hot-rolled coil acid-cleaned to remove scale, then lightly oiled.
- Hot-rolled steel that has undergone two additional processes: first, it is pickled in an acid bath to remove the dark, brittle surface layer of mill scale, and second, it is oiled to provide temporary protection against rust. HRPO offers a cleaner surface than standard hot-rolled steel, making it ideal for painting and laser cutting.
Source(s): usmadesupply.com, chesterfieldsteel.com
See also: Hot-Rolled Steel (HR), Mill Scale
Structural Steel (SS)
Sheet steel produced to guaranteed minimum mechanical properties.
- A designation within ASTM standards (e.g., A1011) for steel that is produced to meet guaranteed minimum mechanical properties, such as yield strength and tensile strength. This makes it suitable for load-bearing and structural applications.
Source(s): ssab.com, usmadesupply.com
Substrate
Base metal — typically a coil of sheet steel — to which a coating is applied.
- The base metal, typically a coil of steel sheet, to which a coating (such as zinc, aluminum-zinc alloy, or paint) is applied.
Source(s): harvardsteelsales.com, steel.org
Coatings
ASTM A792 / A792M
Standard for steel sheet coated with a 55% aluminum-zinc alloy (Galvalume).
- The standard specification from ASTM International that governs steel sheet coated with a 55% aluminum-zinc alloy via a continuous hot-dip process. The product is commonly known as Galvalume®.
Source(s): cosasteel.com, ussteel.com, galvalume.com
See also: Galvalume®, AZ50 / AZ55
AZ50 / AZ55
Coating weight designations for Galvalume under ASTM A792.
- Coating weight designations for products under ASTM A792. The number signifies the minimum total coating weight on both sides of the sheet in hundredths of an ounce per square foot. For example, AZ55 specifies a minimum of 0.55 oz/ft². Higher numbers indicate a thicker, more protective coating.
Source(s): ussteel.com, cosasteel.com, steelroofing.com
See also: Galvalume®, ASTM A792 / A792M
Galvalume®
55% aluminum-zinc alloy coated sheet steel (ASTM A792).
- The registered trade name for steel sheet coated with a 55% aluminum-zinc alloy according to the ASTM A792 specification. It is known for its superior long-term corrosion resistance in many atmospheric environments.
Source(s): conklinmetal.com, ussteel.com, galvalume.com
See also: ASTM A792 / A792M, AZ50 / AZ55, Galvanic Corrosion
Galvanic Corrosion
Accelerated corrosion when dissimilar metals contact in an electrolyte.
- An electrochemical process in which one metal corrodes preferentially when it is in electrical contact with another, dissimilar metal in the presence of an electrolyte (like water). This is the principle behind zinc's sacrificial protection of steel — and also the reason Galvalume must not contact copper or lead.
Source(s): roofgideon.com, sheffieldmetals.com, uscooler.com
See also: Galvalume®
Mill Scale
Flaky bluish-black iron-oxide layer formed on hot-rolled steel.
- A flaky, bluish-black oxide layer that forms on the surface of steel when it is heated for processing, such as in hot rolling. It must be removed (e.g., by pickling) before the steel can be effectively painted or coated.
Source(s): chesterfieldsteel.com, usmadesupply.com
See also: Hot Rolled Pickled and Oiled (HRPO)
Zinc-Iron Alloy (Galvanneal)
Hot-dip galvanized sheet heat-treated to form a Zn-Fe alloy surface.
- A type of coated steel (ASTM A653) where a hot-dipped zinc coating is heat-treated, causing the iron from the steel substrate to diffuse into the zinc. This creates a matte gray, zinc-iron alloy surface that is excellent for painting but has less galvanic protection than a pure zinc coating.
Source(s): unitedmetalproducts.info
Processing
Automatic Gauge Control (AGC)
Closed-loop control system that maintains uniform sheet thickness.
- A computerized system integrated into modern rolling mills that uses sensors to continuously measure the thickness of the steel sheet and automatically adjust the gap between the rolls to maintain a highly uniform gauge. Adjustments can be made 50–60 times per second.
Source(s): steel.org
Electric Arc Furnace (EAF)
Mini-mill steelmaking furnace melting scrap with electric arcs.
- A steelmaking furnace in which steel scrap is heated and melted by the heat of electric arcs striking the metal. This process is the cornerstone of the mini-mill model and is significantly more energy-efficient and less carbon-intensive than traditional blast furnace steelmaking.
Source(s): nucor.com
See also: Thin-Slab Casting
Stamping
Forming, cutting, or shaping sheet metal with a die and punch.
- A manufacturing process that uses a die and a punch to form, cut, or shape sheet metal. It is a high-speed, high-volume process well-suited for producing complex, durable components.
Source(s): alekvs.com, ahssinsights.org
See also: Springback, Strain Hardening (n-value)
Thin-Slab Casting
Casting steel directly into ~2-inch slabs for direct rolling (Nucor process).
- A revolutionary steelmaking process, pioneered by Nucor, where molten steel is cast directly into a slab approximately two inches thick, which can then be rolled into sheet. This process is far more efficient in terms of capital cost, energy, and physical footprint than traditional thick-slab casting.
Source(s): nucor.com, gem.wiki
See also: Electric Arc Furnace (EAF)
Dimensions & Tolerances
Camber
Deviation of a slit edge from a straight line.
- The deviation of a side edge of a steel sheet or strip from a straight line. It is measured as the maximum distance between the concave edge and a straightedge connecting the ends of the strip. Tolerances for camber are defined in standards like ASTM A568.
Source(s): steel.org, miamivalleysteel.com
Coil Breaks
Transverse creases from coiling or uncoiling under tension.
- Creases or ridges appearing on a steel sheet, typically transverse to the rolling direction. They occur when the steel is coiled or uncoiled under tension and can affect the surface appearance of the final product.
Source(s): harvardsteelsales.com, miamivalleysteel.com
Flatness
Measure of deviation from a perfectly flat plane.
- The measure of a sheet's deviation from a perfectly flat plane. Tolerances for flatness are defined in standards like ASTM A480 and A568 and are critical for ensuring proper fit-up in subsequent manufacturing processes.
Source(s): rolledalloys.com, store.astm.org
Gauge
Numerical system used to specify sheet steel thickness.
- A numerical system traditionally used to specify the thickness of a steel sheet. For steel sheet, a higher gauge number corresponds to a thinner sheet. Modern practice increasingly favors specifying thickness by decimal inches or millimeters for greater precision.
Source(s): superiorsteelsupply.us, industrialmetalsupply.com
Tolerance
Permissible range of variation from a specified dimension.
- The permissible range of variation from a specified dimension (e.g., thickness, width, or flatness) for a steel product. These ranges are officially defined in ASTM standards like A568 and A480.
Source(s): rolledalloys.com, steel.org, industrialmetalsupply.com
Quality & Testing
Aging
Change in mechanical properties of low-carbon sheet over time.
- The change in the mechanical properties of low-carbon steel sheet that occurs with the passage of time. These changes, which can be detrimental, may include an increase in hardness and yield strength, with a corresponding decrease in ductility.
Source(s): harvardsteelsales.com, miamivalleysteel.com
Certified Mill Test Report (CMTR)
Mill-issued certification of chemistry and mechanical properties.
- A formal quality assurance document, also known as a Mill Test Report (MTR), issued by a steel mill that certifies a specific batch (or heat) of steel complies with the chemical composition and mechanical property requirements of a given standard (e.g., ASTM, SAE). It is the material's birth certificate.
Source(s): aisc.org, wermac.org, certivo.com
See also: Heat Number, Positive Material Identification (PMI)
Elongation
Percent stretch before fracture — a measure of ductility.
- A measure of a material's ductility, expressed as a percentage. It represents how much a test piece of steel can be stretched before it fractures. Higher elongation values are critical for deep drawing and complex forming operations.
Source(s): baobingroup.com, wermac.org
Erichsen Cupping Test
Mechanical test of sheet ductility and formability via a cupping punch.
- A mechanical test used to assess the ductility and formability of sheet metal. It measures the depth of impression (the Erichsen Index) that a standard punch can make in the sheet before a crack appears. A higher index indicates better stretchability.
Source(s): baobingroup.com
Heat Number
Unique mill identifier for a single furnace batch of steel.
- A unique alphanumeric code assigned by a steel mill to a specific batch of molten steel produced in a single furnace run. This number is the primary key for traceability, linking the finished steel product back to its specific chemical and mechanical test data on the MTR.
Source(s): aisc.org, industrialmetalsupply.com, certivo.com
See also: Certified Mill Test Report (CMTR)
IATF 16949
International automotive quality management system standard.
- The international quality management system standard for the automotive industry. It mandates rigorous process control, risk management, and full material traceability for all components in the automotive supply chain.
Source(s): meadmetals.com, zetarmold.com, aiag.org
Positive Material Identification (PMI)
Non-destructive verification of alloy chemistry (often via XRF).
- A non-destructive testing method, often using a portable X-ray fluorescence (XRF) analyzer, to verify the chemical composition of a metal or alloy. It is used as a quality assurance tool to confirm that the material received matches the specifications on its MTR.
Source(s): northernmfg.com
See also: Certified Mill Test Report (CMTR)
Springback
Elastic recovery of metal after a forming operation.
- The elastic recovery of metal after a forming operation. The material springs back slightly toward its original shape after the forming pressure is released. This effect is more pronounced in high-strength steels and must be compensated for in die and tool design to achieve final part accuracy.
Source(s): ahssinsights.org, alekvs.com
Strain Hardening (n-value)
How much a metal strengthens as it is plastically deformed.
- A measure of how much a metal strengthens as it is plastically deformed. A high n-value is desirable in forming operations because it helps distribute strain more evenly across the part, preventing localized thinning and potential failure.
Source(s): baobingroup.com
Yield Strength
Stress at which a material begins to deform plastically.
- The amount of stress at which a material begins to deform plastically. Before reaching the yield point, the material will deform elastically and return to its original shape when the load is removed. It is a critical property for structural design.
Source(s): wermac.org, baobingroup.com
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