Stainless steel / UNS S30403
304L is the low-carbon version of 304. Its 0.03% maximum carbon prevents carbide precipitation during welding, so heavy welded sections keep their intergranular corrosion resistance.
- UNS S30403
- W.Nr. 1.4307
- Spec ASTM A240
- Density 7.93 g/cm³
Also known as / equivalents
| System | Designation |
|---|---|
| UNS | S30403 |
| W.Nr. | 1.4307 |
| EN | X2CrNi18-9 |
| JIS | SUS304L |
| Also known as | AISI 304L, 1.4307, 1.4306, SUS304L |
Chemical composition
| Element | Min % | Max % |
|---|---|---|
| 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 |
| Fe | Bal. | — |
Mechanical properties
| Property | Value |
|---|---|
| Tensile strength (min) | 485 MPa (70.3 ksi) |
| Yield strength, 0.2% offset (min) | 170 MPa (24.7 ksi) |
| Elongation in 50 mm (min) | 40 % |
| Hardness | 201 HB max |
Physical properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 7.93 g/cm³ | 0.286 lb/in³ |
| Magnetic response | Non-magnetic when annealed; may become slightly magnetic after cold work | — |
Available forms & specifications
| Form | Specification | Size range |
|---|---|---|
| Sheets, plates & coils | ASTM A240 / ASME SA240 | 0.3 mm – 6 mm |
| Seamless & welded pipe | ASTM A312 / ASME SA312 | 1/8" – 24" NB |
| Tubes | ASTM A213, A249, A269 | 1/8" – 24" NB |
| Bars & rods | ASTM A276, A479 | 3 mm – 500 mm |
| Flanges & forgings | ASTM A182 / ASME SA182 | 1/2" – 48" NB (larger on request) |
| Buttweld fittings | ASTM A403 / ASME SA403 | 1/2" – 48" NB |
| Fasteners | ASTM A193 / A194, F593 / F594 | M3 – M56 |
Corrosion & temperature resistance
Corrosion resistance rises with chromium, molybdenum and nitrogen: 304 handles general atmospheric and food-contact service, 316/317 add resistance to chlorides and pitting, 904L handles strong reducing acids, and stabilised 321/347 resist intergranular attack after welding or high-temperature exposure.
Applications
SS 304L: Welded vessels, piping, chemical tanks. Process piping, tanks and vessels, heat exchangers, food, dairy and pharmaceutical equipment, architectural work and general engineering.
SS 304L vs SS 304
| SS 304L | SS 304 | |
|---|---|---|
| UNS | S30403 | S30400 |
| Key property | Low carbon for welded construction | General-purpose 18/8 austenitic |
| Typical use | Welded vessels, piping, chemical tanks | Food, dairy, tanks, piping, architecture |
| Cr (wt %) | 17.5–19.5 | 17.5–19.5 |
| Ni (wt %) | 8.0–12.0 | 8.0–10.5 |
| Mo (wt %) | — | — |
| C (wt %) | ≤ 0.030 | ≤ 0.07 |
| Tensile / yield (min, MPa) | 485 / 170 | 515 / 205 |
Frequently asked questions
What is the UNS number of SS 304L?
SS 304L is designated UNS S30403 (W.Nr. 1.4307, EN X2CrNi18-9).
What is SS 304L used for?
Low carbon for welded construction. Typical uses: welded vessels, piping, chemical tanks.
Is SS 304L magnetic?
Non-magnetic when annealed; may become slightly magnetic after cold work.
In which forms can I buy SS 304L from Rajkamal Metals?
Coils & Strips, Sheets & Plates, Pipes & Tubes, Round Bars & Rods, Structural Sections, Flanges, Buttweld Fittings, Socket Weld & Threaded Fittings, Fasteners, Ferrule / Instrumentation Fittings, Dairy Fittings, Dish Ends, SS Tanks, Custom Orders. Sizes as per standard; other sizes on request.
Do you supply a Mill Test Certificate with SS 304L?
Yes. Actual values are given in the Mill Test Certificate (EN 10204 3.1) supplied with each order.
What is the difference between SS 304L and SS 304?
SS 304L: low carbon for welded construction. SS 304: general-purpose 18/8 austenitic. See the comparison table on this page.
Last updated: 30 October 2026. Grade names identify the supply range; designations are not engineering equivalents. Availability, make, origin and documentation are confirmed at quotation.
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