Are cross-referenced grades exactly identical?

They are nearest equivalents, not perfect matches. Standards define slightly different composition ranges and tolerances, so an AISI 4140 and its EN 42CrMo4 counterpart are interchangeable for most purposes but may differ at the edges of their specs. Confirm critical properties against the actual standard.

What do the AISI four-digit numbers mean?

The first two digits give the alloy family and the last two give carbon content in hundredths of a percent. 1045 is plain carbon (10xx) with 0.45 percent carbon; 4140 is chromium-molybdenum (41xx) with 0.40 percent carbon.

How do I read an EN steel number like 1.7225?

The leading 1 means steel, the next two digits are the steel group (72 is Cr-Mo alloy), and the last two identify the specific grade. 1.7225 is the EN number for 42CrMo4, equivalent to AISI 4140.

What is the difference between 304 and 316 stainless?

Both are austenitic chromium-nickel stainless steels, but 316 adds about 2 percent molybdenum for much better resistance to chlorides and pitting. 316 is preferred for marine and chemical environments; 304 is the general-purpose default.

Can I substitute a grade from a different standard?

Often yes, using the nearest equivalent, but verify the mechanical properties, heat-treatment response, and any code requirements your application imposes. Pressure-vessel and structural codes may only accept specific named grades regardless of equivalence.

What is the Steel Alloy Grade Reference?

Cross-reference common carbon, alloy, and stainless steel grades across AISI/SAE, EN, DIN, and JIS standards, with typical composition and notes. Search by any standard's grade name. It runs free in your browser on Gera Tools, with nothing uploaded.

Steel Alloy Grade Reference

Name: Steel Alloy Grade Reference
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

Steel is specified differently in every region — AISI in North America, EN and DIN in Europe, JIS in Japan. This reference cross-maps common grades across all four systems and gives the composition family so you can substitute safely.

How it works

Each row pins the same steel to its name in every standard. The mapping is built on composition: an AISI 41xx chromium-molybdenum steel with 0.40 percent carbon (4140) is the same family as EN 42CrMo4 / 1.7225 and JIS SCM440, so those names all appear in one row.

AISI four-digit codes are themselves readable: the first two digits are the alloy family and the last two are carbon content in hundredths of a percent. So 1045 is plain-carbon steel with 0.45 percent carbon, and 4340 is a nickel-chromium-moly steel with 0.40 percent carbon.

The search matches any token in any column, so you can start from whichever standard you happen to have.

Common grade families and their applications

Plain carbon steels (10xx / S235–S355 / C45E). These are the workhorse grades. Low-carbon (1018, 1020) are easily welded and machined; mid-carbon (1045, 1050) are tougher and take heat treatment; high-carbon (1080, 1095) are used for springs and cutting tools. EN structural equivalents like S275 and S355 appear in fabrication drawings rather than AISI designations.

Chromium-molybdenum steels (41xx / 42CrMo4 / SCM440). The most widely used alloy steel family for shafts, gears, bolts, and structural parts requiring strength and toughness. 4130 (thinner sections, weldable) and 4140 (heavier sections, deeper hardenability) are the common choices. Their EN counterpart is 42CrMo4, DIN number 1.7225, and JIS SCM440.

Nickel-chromium-molybdenum steels (43xx / 36CrNiMo / SNCM). 4340 is in this family — extremely high strength and deep hardenability, used for aircraft parts, large-diameter shafts, and heavy ordnance components where 4140 lacks sufficient hardenability through the section.

Stainless steels (300 and 400 series / EN 10088 / SUS). The 304 and 316 grades are austenitic (non-magnetic, excellent corrosion resistance). 316 adds about 2% molybdenum versus 304, giving markedly better chloride resistance for marine, food-processing, and chemical environments. The 400-series grades (410, 420, 440C) are martensitic, heat-treatable, and magnetic — common in cutlery, surgical instruments, and bearings.

Reading an EN material number

The EN numbering system encodes information in the four digits after the decimal:

The leading 1 means iron-based steel.
The next two digits (00–99) indicate the steel group (e.g., 72 = Cr-Mo alloy steels).
The last two digits identify the specific grade within the group.

So 1.4301 is austenitic stainless (group 43 = austenitic Cr-Ni steels), specifically the EN designation for 304. And 1.4401 is the 316 equivalent.

Notes on substitution

Cross-references are nearest equivalents — composition ranges differ slightly between standards. Verify critical properties such as tensile strength, yield strength, and Charpy impact values if the application is load-bearing. For code-governed work (pressure vessels, structural steel, aerospace), the specific named grade in the relevant standard may be mandatory even when a compositional equivalent exists. Heat-treatment response and hardenability can diverge even for nominal equivalents, particularly in larger cross-sections.