Material number 1.4307: 304L
1.4307 is the European material number (Werkstoffnummer, EN 10027-2) for 304L, low-carbon austenitic chromium-nickel stainless steel specified in ASTM A240.
Reading 1.4307 digit by digit
An EN 10027-2 number has the form 1.XXYY. The leading 1 marks it as steel. The pair 43 is the steel group, and for this number that group is stainless steels with ≥ 2.5 % Ni, no Mo. The final pair 07 is a sequential count inside that group and carries no meaning of its own — 1.4307 is simply the 7th entry registered there.
The group digits are the useful part. Reading 43 tells you what kind of steel you are looking at before you know anything else about it, and the 2 other numbers from group 43 held here are listed below.
1.4307 identity card
| Item | Value |
|---|---|
| Material number (EN 10027-2) | 1.4307 |
| Symbolic grade name | 304L |
| Steel group | 43 — stainless steels with ≥ 2.5 % Ni, no Mo |
| Sequential number in group | 07 |
| Specified in | ASTM A240 |
| Steel family | Stainless steel |
| Also carries UNS | S30403 |
| Yield, first condition in the table | ≥ 170 MPa (sheet/plate, annealed (ASTM A240)) |
| Tensile, same condition | ≥ 485 MPa |
| Cross-references held | 7 grades in 5 systems |
304L (1.4307, UNS S30403) is 304 with carbon capped at 0.030 %: the same 18/8 alloy, specified so that welds do not sensitise.
Full data sheet for 304L → · Equivalent grades → · ASTM A240 →
Group 43 — the neighbouring numbers
Same group digits, so the same broad class of steel. The sequential digits do not rank them.