Your browser is out of date.

You are currently using Internet Explorer 7/8/9, which is not supported by our site. For the best experience, please use one of the latest browsers.


Standards are proprietary information, so this page will only cover what information is described by common specifications.

SAE - Society of Automotive Engineers
Currently focused on developing Advanced High Strength Steels

ASTM - American Society for Testing Materials
North America's collective organization for material standards; emphasizes testing results for certification

EN - Euronorm
Europe's organization for material standards

JIS - Japanese Industrial Standards
The letter following JIS denotes the category; "G" is ferrous/metallurgy, and "H" is non-ferrous/metallurgy

*Note: there are many other material standard organizations. Specifications can be related, but many times a specification will not directly translate to a specification from a different organization.

UNS (United Numbering System)

Steel grades are classified using a 4-digit series of numbers. The first two digits specify the type of steel, and the second two digits specify the percentage of carbon in the grade.

First Two Digits:

1xxx   Carbon steel - no alloys

10xx   Plain carbon steel

11xx   Free-machining steels (S. Mn, P)

13xx   Intermediate Mn steels

4xxx   Molybdenum steels

5xxx   Chromium steels

6xxx   Chromium-vanadium steels

8xxx   Triple alloy (Ni, Cr, Mo)

92xx   Silicon-manganese steels

Second Two Digits:

Percentage of carbon required


1010 is 0.08% - 0.13%

1018 is 0.15% - 0.20%



1008 is 0.10% max C

1006 is 0.08% max C



SAE J2340 addresses high strength low alloy steel grades. It supersedes J1392.

Note: General Motors formed the basis for the original J1392, and they denoted grade 50 by using "950." The current version of J2340 denotes grades 50 by "050."

X: 10 ksi minimum spread between the yield strength and tensile strength

Y: 15 ksi minimum spread between the yield strength and tensile strength

Z: 20 ksi minimum spread between the yield strength and tensile strength

L: Lower maximum carbon percentage (often 0.13%)

H: Higher maximum carbon percentage

W: Weathering steel

S: Structural steel (C-Mn strengthened only)

K: Killed, fine grain practice

F: Sulfide inclusion controlled, fine grain practice *

*Most steel, regardless of K and F designation, is killed and sulfide inclusions are controlled



ASTM uses test results as validation; if representative samples meet the specification's requirements, the material can be certified to that specification.

A6 Standard Specification for General Requirements for Rolled Structural Steel Bars, Plates, Shapes, and Sheet Piling. 63 pages of required testing, permitted variations, manufacturing, delivery, etc.

A36 Standard Specification for Structural Steel. Very high volume grade. Wide chemistry range, but requires a 36 ksi minimum yield strength.

A514 Standard Specification for High-Yield-Strength, Quenched and Tempered Alloy Steel Plate, Suitable for Welding. Lists allowable chemical analyses for a family of plate products of 100 ksi yield strength. Available at greater thicknesses than A656 grade 100. Does not allow plate from coil.

A568 General Requirements for Steel, Sheet, Carbon and High-Strength Low Alloy, Hot-Rolled and Cold-Rolled. Covers terminology, materials, and product tolerances.

A572 Standard Specification for High-Strength Low Alloy Columbium-Vanadium Structural Steel. Lists five chemical recipes and five different mechanical property ranges for plate products (grades 42, 50, 55, 60, and 65). Relatively wide chemical and property ranges. Grade 50 high volume.

A635 General Requirements for Steel, Sheet and Strip, Heavy-Thickness Coils, Hot-Rolled, Carbon, Structural, High-Strength Low Alloy, Columbium or Vanadium, and High-Strength Low Alloy with Improved Formability. Covers terminology, materials, and product tolerances.

A656 Standard Specification for Hot-Rolled Structural Steel, High-Strength Low Alloy Plate with Improved Formability. Lists two possible chemical variations for steels (grades 50, 60, 70, 80, and 100). Grades 80 and 100 are the highest volumes. More demanding property and chemistry requirements than A572.

A673 Standard Specification for Sampling Procedure for Impact Testing of Structural Steel. A supplemental standard that covers the procedure for longitudinal Charpy testing. Orientation, sampling, and other parameters are referenced in ASTM A370 (Standard Test Methods and Definitions for Mechanical Testing of Steel Products).

A709 Standard Specification for Structural Steel Bridges. Covers carbon, HSLA, Q&T, and stainless steel plates, bars, and shapes for structural use in bridges. Includes grades 36, 50, 70, and 100, with designations for enhanced atmospheric corrosion resistance (W). Both fracture critical tension components and non-critical fracture tension components must meet impact requirements. These requirements are based on American Association of State Highway and Transportation Officials (AASHTO) requirements for tension components in bridges.

A1011 Standard Specification for Steel, Sheet and Strip, Hot-Rolled, Carbon, Structural, High-Strength Low-Allow, High-Strength Low-Alloy with Improved Formability, and Ultra-High Strength. Covers CS, DS, and grade 30 up to grade 90.

A1018 Standard Specification for Steel, Sheet and Strip, Heavy-Thickness Coils, Hot-Rolled, Carbon, Commercial, Drawing, Structural, High-Strength Low-Alloy, High-Strength Low-Alloy with Improved Formability, and Ultra-High Strength. Covers CS, DS, and grade 30 up to grade 80 for COILS ONLY!

Plate versus Sheet


Plate ("structural products")

General requirements are outlined in A6

Commonly used plate specifications include:

  • A36
  • A572
  • A656
Sheet thinner than 0.230"

General requirements are outlined in A568

Commonly used sheet specifications include:

  • A1011 (coils and CTL)
Sheet thicker than 0.230"

General requirements are outlined in A635


Commonly used sheet specifications include:

  • A1018 - COILS ONLY!


Euronorm emphasizes the pedigree of the mill document;if the steel mill produced steel to a specification, the material meets that specification.
10025  Hot rolled products of structural steels; technical delivery conditions
10149  Hot rolled flat products made of high yield strength steel for cold forming; technical delivery conditions

Other Standard Organizations / Specifications

ASME, The American Society of Mechanical Engineers. Includes PVQ (Pressure Vessel Quality) specifications. PVQ specifications SA36, SA414, and SA516 are based on ASTM specifications A36, A414, and A516, with psi requirements for boiler and pressure vessel codes.
JIS,JapaneseIndustrialStandards.Steel specifications with very little definition on chemistry - grades are predominantly based on mechanical properties.
CSA, Canadian Standards Association. One frequently used specification is G40.21, which includes 44W (300W in metric), a structural grade. 44WT (300WT) designates Charpy requirements.

Explore Our Available Steel Products & Grades

Our knowledge and experience give nearly 100% accurate delivery of High Carbon, Low Carbon, Stainless Steel products processed and packaged to your exact specifications.

See All Resources

Have a Question?
Our experts can help

Give us a call at 800-348-2529 or leave us a message.

Speak to a Steel Expert