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.

Steel Alloy Grade Reference

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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.

Tips and notes

Cross-references are nearest equivalents — composition ranges differ slightly between standards, so verify critical properties.
For stainless, 304 is the general-purpose grade and 316 adds molybdenum for chloride resistance.
Code-governed work (pressure vessels, structural steel) may require a specifically named grade even when an equivalent exists.
Heat-treatment response varies between near-equivalents; confirm hardenability if the part is quenched and tempered.