Stainless 304L (UNS S30403)
Stainless 304L (UNS S30403) — Low-carbon 304 for welded construction; resists sensitisation.
| UNS number | S30403 |
| Material family | Austenitic stainless |
| Product specifications | A182 F304L, A403 WP304L, A312 TP304L |
| Density (typical) | 7.93 g/cm³ (7930 kg/m³) |
| Weight of 6" Sch 40 pipe | 28.55 kg/m |
Specifications by product form
One alloy is ordered under different ASTM/ASME numbers depending on form: forged flanges and fittings, wrought buttweld fittings, and pipe or tube. For Stainless 304L the usual specifications are A182 F304L, A403 WP304L, A312 TP304L. Quote both the specification and the UNS number on purchase orders to avoid ambiguity.
Chemical and mechanical limits differ between these specifications — always check the edition of the standard named on your order and the mill test certificate.
Chemical composition & mechanical properties
| Property | SS 304L |
|---|---|
| Family | Austenitic stainless |
| UNS | S30403 |
| EN / W.Nr | 1.4307 X2CrNi18-9 |
| Basis spec | ASTM A240 |
| Density g/cm³ | 7.93 |
| Chemical composition, % | |
| C | 0.030 |
| Mn | 2.00 |
| P | 0.045 |
| S | 0.030 |
| Si | 0.75 |
| Cr | 17.5–19.5 |
| Ni | 8.0–12.0 |
| N | 0.10 |
| Mechanical properties (min) | |
| Tensile strength | 485 MPa (70 ksi) |
| Yield strength (0.2%) | 170 MPa (25 ksi) |
| Elongation | 40% |
| Hardness (max) | 201 HB |
| PREN (min, from spec) | 17.5 |
Single values are maximums; ranges are min–max; "bal" = balance. Limits are typical of the basis specification for that product form — forgings, pipe and fittings specifications differ slightly. Always check the exact specification, edition and the mill test certificate.
Frequently asked questions
What is the UNS number of Stainless 304L?
S30403.
Which ASTM specifications cover Stainless 304L?
A182 F304L, A403 WP304L, A312 TP304L.
What is the density of Stainless 304L?
About 7.93 g/cm³ (7930 kg/m³), used for weight calculations.
Last updated 2026-11-02