Stainless 304 / 304L · UNS S30400 / S30403 · W. Nr. 1.4301 / 1.4307
Stainless 304 / 304L (S30400 / S30403): composition, properties, fittings and flanges
Stainless 304 / 304L (S30400 / S30403, W. Nr. 1.4301 / 1.4307) is Austenitic chromium-nickel stainless steel (18/8). Stainless 304 / 304L is specified at Chromium 18.0 - 20.0, Nickel 8.0 - 10.5 (304) / 8.0 - 12.0 (304L). 304 is the world's most used stainless steel and 304L is its weldable low-carbon twin: the L grade drops…
- UNS
- S30400 / S30403
- W. Nr.
- 1.4301 / 1.4307
- Density
- 8.00 g/cm³ (0.289 lb/in³)
- Key strength
- 515 MPa / 75 ksi (304) · 485 MPa / 70 ksi (304L)
Identification and standards
| Short form | Stainless 304 / 304L · UNS S30400 / S30403 · W. Nr. 1.4301 / 1.4307 |
|---|---|
| Classification | Austenitic chromium-nickel stainless steel (18/8) |
| UNS | S30400 / S30403 |
| Werkstoff number | 1.4301 / 1.4307 |
| Material family | Stainless Steel |
Chemical composition
| Element | Composition (wt %) | Why it is there |
|---|---|---|
| Chromium (Cr) | 18.0 - 20.0 | Passive film and oxidation resistance |
| Nickel (Ni) | 8.0 - 10.5 (304) / 8.0 - 12.0 (304L) | Austenite stability |
| Carbon (C) | 0.08 max (304) / 0.030 max (304L) | Controls intergranular corrosion |
| Manganese (Mn) | 2.00 max | - |
| Silicon (Si) | 0.75 max | - |
| Phosphorus (P) | 0.045 max | - |
| Sulphur (S) | 0.030 max | Machinability |
| Iron (Fe) | Balance | Matrix |
Note Single figures are maximum limits unless shown as a range. Always confirm against the heat-specific EN 10204 3.1 certificate supplied with your order.
Mechanical properties
| Tensile strength, min (annealed) | 515 MPa / 75 ksi (304) · 485 MPa / 70 ksi (304L) |
|---|---|
| 0.2 % yield strength, min | 205 MPa / 30 ksi (304) · 170 MPa / 25 ksi (304L) |
| Elongation in 2 in, min | 40 % |
| Typical hardness, annealed | 145 - 190 HB |
| PREN, typical | About 19 |
Warning Values depend on product form, section thickness and heat treatment. Larger sections generally achieve lower strength than thin product; always design against the applicable code allowable stress rather than these figures.
Physical properties
| Density | 8.00 g/cm³ (0.289 lb/in³) |
|---|---|
| Melting range | 1400 - 1450 °C (2550 - 2640 °F) |
| Modulus of elasticity | 193 GPa (28.0 x 10⁶ psi) |
| Thermal conductivity at 20 °C | 16.2 W/m·K |
| Mean coefficient of thermal expansion, 20-100 °C | 17.3 µm/m·°C |
| Specific heat capacity | 500 J/kg·K |
Specifications by product form
| Forgings & flanges | ASTM A182 F304 / F304L · ASME SA-182 |
|---|---|
| Butt weld fittings | ASTM A403 WP304 / WP304L · ASME SA-403 |
| Seamless pipe & tube | ASTM A312 TP304 / TP304L · ASME SA-312 |
| Plate / sheet / strip | ASTM A240 304 / 304L · ASME SA-240 |
| Bar / rod | ASTM A276 / A479 |
| Welding consumables | ER308L for 304L, ER308 for 304 |
| UNS / EN / China | UNS S30400 / S30403 · W. Nr. 1.4301 / 1.4307 · GB 06Cr19Ni10 / 022Cr19Ni10 |
Product forms available
Hangbo supplies this grade in the following forms. Sizes outside the listed range can often be produced to order.
- Forged flanges blanks and finished flanges to ASME B16.5, B16.47 Series A/B and B16.36
- Butt weld elbows, tees, reducers, caps and stub ends to ASME B16.9 and MSS SP-43
- Seamless pipe and tube to the applicable ASTM / ASME pipe specification
- Forged rings, discs and hubs machined to your drawing
Typical applications
- General chemical, food, dairy and beverage process piping
- Architectural, sanitary and potable water systems
- Cryogenic vessels and piping to -196 °C
- Heat exchanger tubes and instrument lines
Welding, forming and machining
- Welding
- Weld 304L with ER308L filler. Low carbon means no post-weld anneal is needed for corrosion service; 304 with higher carbon may need stabilisation or annealing on heavy sections.
- Heat treatment
- Solution anneal at 1010 - 1120 °C and water quench. Stress relieve at 815 °C only when sensitisation is not a concern.
- Hot and cold forming
- Hot work in the range stated by the mill for this grade, then re-solution or re-age before final machining so that the delivered condition matches the certificate.
- Machining
- Machine with sharp carbide or high-speed steel tooling, positive rake, constant feed and ample coolant. Never dwell - the surface work-hardens quickly.
Buy Stainless 304 / 304L from Hangbo
Material is supplied with full heat-number traceability, solution annealing or ageing performed under calibrated furnace control, and an EN 10204 3.1 certificate covering chemical analysis, mechanical properties, heat treatment records and the agreed NDT scope. Positive material identification and third party inspection and test reports from SGS are available for critical service.