Stainless Steel
Stainless Steel 304 / 304L
The default austenitic stainless. 18% Cr, 8% Ni — most-stocked SS in India.
SS 304 is the default austenitic stainless steel. Excellent atmospheric and chemical corrosion resistance, fully non-magnetic in annealed condition, weldable. 304L variant has lower carbon (0.030% max) for welded service to avoid sensitisation.
Equivalent Designations
| Standard | Designation |
|---|---|
| UNS | S30400 (304) / S30403 (304L) |
| Werkstoff Nr. | 1.4301 / 1.4307 |
| JIS | SUS 304 / SUS 304L |
| BS | 304S31 / 304S11 |
| AFNOR | Z7CN18-09 / Z3CN18-10 |
| EN | X5CrNi18-10 / X2CrNi19-11 |
Standards
ASTM A276 / A479 (bars)ASTM A240 / ASME SA240 (plate, sheet, strip)ASTM A312 / A213 (pipe, tube)EN 10088-3 (long products)DIN 17440
Chemical Composition (% by mass)
| C (304 / 304L) | 0.08 max / 0.030 max |
| Mn | 2.0 max |
| P | 0.045 max |
| S | 0.030 max |
| Si | 1.0 max |
| Cr | 18.0–20.0 |
| Ni | 8.0–11.0 (304); 8.0–12.0 (304L) |
Mechanical Properties
| Tensile Strength | 515 MPa (75 000 psi) |
| Yield Strength (0.2%) | 205 MPa (30 000 psi) |
| Elongation | 35 % |
Physical Properties
| Density | 8.0 g/cm³ |
| Melting Point | 1400 °C (2550 °F) |
Available Forms & Sizes
| Form | Size Range | Notes |
|---|---|---|
| Round Bar (hot-rolled) | Ø4 mm to Ø500 mm | — |
| Bright Bar (cold-finished) | Ø4 mm to Ø100 mm | — |
| Hex Bar | 18 mm to 57 mm A/F (11/16″ to 2-3/4″) | — |
| Square Bar | 18 mm to 47 mm (11/16″ to 1-3/4″) | — |
| Flat Bar | 1/2″ to 10″ width × 2 mm to 150 mm thick | — |
| Plate/Sheet | 1.2 mm to 100 mm thick × 1000×2000 or 1250×2500 mm | — |
Finishes Available
BlackBright PolishedRough TurnedNo.4MattBA
Use Cases
Food & beverage processing
Tanks, conveyor frames, mixer impellers, hoppers. 304 is the default; specify 304L for welded vessels to avoid sensitisation.
Architectural cladding & balustrades
2B, BA, or No.4 finish for hairline brushed look.
Lab equipment, vacuum chamber walls
Non-magnetic in annealed condition; demands 304L for welded UHV chambers.
Chemical handling — limited
Fine for nitric acid; switch to 316 for any chloride exposure.
Design Notes
- 304 work-hardens during machining → use sharp positive-rake tools, avoid dwelling.
- Magnetic permeability rises after cold work (drawn bar can be slightly magnetic). For non-magnetic critical applications, specify "non-magnetic, μᵣ < 1.05" and demand annealing.
- Visually identical to 316 — verify with PMI for chloride service.