304L Stainless Steel (UNS S30403)
Austenitic (low carbon) · ASTM A240/A240M · Density 7.93 g/cm³
304L (UNS S30403) is the low-carbon version of 304 stainless steel. Carbon is limited to 0.030% to reduce sensitization risk during welding and preserve corrosion resistance in the heat-affected zone. Dual certification as 304/304L is valid only when the ordered product and material certificate meet both sets of requirements.
Chemical Composition (wt%)
| C | Mn | Si | Cr | Ni | P | S | N |
|---|---|---|---|---|---|---|---|
| ≤0.030 | ≤2.00 | ≤0.75 | 17.5–19.5 | 8.0–12.0 | ≤0.045 | ≤0.030 | ≤0.10 |
Single values are maximums unless a range is shown. Balance: Fe. Per ASTM A240/A240M.
Mechanical Properties
| Tensile strength | ≥485 MPa (70 ksi) |
|---|---|
| Yield strength (0.2%) | ≥170 MPa (25 ksi) |
| Elongation (50 mm) | ≥40% |
| Hardness | ≤201 HBW |
Room-temperature minimum values are summarized for annealed flat product under ASTM A240/A240M unless a condition is named in the property label; product form and thickness can change the requirement.
Physical Properties & Structure
| Density | 7.93 g/cm³ |
|---|---|
| Magnetic response | Essentially non-magnetic after solution annealing; cold work can introduce a measurable magnetic response. |
| Microstructure | Austenitic (low carbon) |
Corrosion Resistance & Limits
- General corrosion resistance comes from the chromium-rich passive film; nickel, molybdenum, nitrogen and copper change performance by grade.
- Check chlorides, temperature, crevices, deposits, process chemistry and cleaning conditions. A grade designation alone is not a service-life guarantee.
Fabrication & Heat Treatment
| Welding | Generally weldable with a qualified procedure and matching or over-alloyed filler where required; remove heat tint when corrosion service demands it. |
|---|---|
| Forming | Good ductility is typical, but rapid work hardening increases forming load and springback; bend radius and intermediate annealing depend on grade and reduction. |
| Machining | Use rigid tooling, positive feeds and controlled heat because the material work-hardens; free-machining grades require separate corrosion and welding review. |
| Heat treatment | Solution annealing and rapid cooling restore the intended condition where applicable. Austenitic grades are not hardened by conventional quench-and-temper treatment. |
Equivalent Grades
The closest international equivalents of 304L Stainless Steel are 1.4307 (X2CrNi18-9) in the EN system, SUS304L in the JIS system, 022Cr19Ni10 in the GB system.
These are common corresponding designations, not unconditional substitutes. Verify chemistry, mechanical properties, product standard, delivery condition, dimensions and project approval before changing designation.
| System | Designation |
|---|---|
| UNS | S30403 |
| EN | 1.4307 (X2CrNi18-9) |
| JIS | SUS304L |
| GB | 022Cr19Ni10 |
Reference Product Forms & Dimensional Ranges
Common reference product forms for 304l stainless steel: Sheet / Plate, Coil / Strip, Pipe / Tube, Bar.
| Finishes | No.1, 2B, BA, No.4 |
|---|---|
| Sheet / coil thickness | 0.3–6.0 mm |
| Plate thickness | 6–60 mm |
Common surface and delivery options: No.1, 2B, BA or mechanically polished finish when supported by the product route; Annealed and pickled, descaled or polished tube finish as specified; Hot rolled, peeled, bright drawn, ground or polished bar condition according to tolerance.
These published ranges are engineering references, not a live-stock or production-capability promise. Confirm the required product form, dimensions, condition, finish and supply route in the quotation.
Typical Applications
- Welded tanks and vessels
- Chemical and process piping
- Food processing equipment
- Heat exchangers
304L Products We Export
304 Stainless Steel Sheet
304/304L stainless steel sheet in 2B, BA, No.4 and mirror finish, in quotation-confirmed dimensions, cut to size, with ordered documentation.
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304 Stainless Steel Welded Pipe
304 welded stainless steel pipe and tube to ASTM A312, A249 and A554 — industrial, sanitary and polished decorative, round, square and rectangular sections.
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Frequently Asked Questions
What is the difference between 304 and 304L?
Only the carbon limit: 0.08% for 304 versus 0.030% for 304L. Lower carbon prevents chromium carbide precipitation (sensitization) in weld heat-affected zones, so 304L keeps its corrosion resistance after welding without post-weld annealing. 304L has slightly lower minimum strength.
What does dual certified 304/304L mean?
The material meets 304L's carbon limit and 304's strength minimums at the same time, so one product can satisfy both specifications. Confirm dual certification on the MTC for the ordered product, condition and standard rather than assuming it from the grade label.
When should I specify 304L instead of 304?
Whenever the part will be welded and used as-welded — tanks, pipe systems, structural weldments. If the product is not welded, or is annealed after welding, standard 304 is fine.
304L Compared With Other Grades
Organizational author: Tsingshan (Shandong) Iron & Steel Co., Ltd..Review method, status and limitations.
Other stainless steel grades:
304316316L201321310S4104302205202301309S316Ti347904L409L4204394414442507303317L254 SMO440C17-4 PH2304
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