304 Stainless Steel (UNS S30400)
Austenitic · ASTM A240/A240M · Density 7.93 g/cm³
Type 304 (UNS S30400) is the most widely used austenitic stainless steel, containing roughly 18% chromium and 8% nickel. It offers good corrosion resistance, excellent formability and weldability, and is the default choice for kitchen equipment, food processing, architecture and general fabrication.
Chemical Composition (wt%)
| C | Mn | Si | Cr | Ni | P | S | N |
|---|---|---|---|---|---|---|---|
| ≤0.08 | ≤2.00 | ≤0.75 | 17.5–19.5 | 8.0–10.5 | ≤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 | ≥515 MPa (75 ksi) |
|---|---|
| Yield strength (0.2%) | ≥205 MPa (30 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.
Properties by Condition
304 Annealed (standard supply)
The normal mill condition per ASTM A240 — maximum ductility for deep drawing, bending and general fabrication.
| Tensile strength | ≥515 MPa (75 ksi) |
|---|---|
| Yield strength (0.2%) | ≥205 MPa (30 ksi) |
| Elongation | ≥40% |
304 1/4 Hard (ASTM A666)
Cold rolled for spring-back and structural stiffness in strip products; formability drops accordingly.
| Tensile strength | ≥860 MPa (125 ksi) |
|---|---|
| Yield strength (0.2%) | ≥515 MPa (75 ksi) |
| Elongation | ≥10% (thickness-dependent) |
304 1/2 Hard (ASTM A666)
Higher cold-worked strength for flat springs and clips. Beyond 1/2 hard, grade 301 is the practical choice — it work-hardens faster with better retained ductility.
| Tensile strength | ≥1035 MPa (150 ksi) |
|---|---|
| Yield strength (0.2%) | ≥760 MPa (110 ksi) |
| Elongation | ≥6% (thickness-dependent) |
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 |
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 304 Stainless Steel are 1.4301 (X5CrNi18-10) in the EN system, SUS304 in the JIS system, 06Cr19Ni10 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 | S30400 |
| EN | 1.4301 (X5CrNi18-10) |
| JIS | SUS304 |
| GB | 06Cr19Ni10 |
Reference Product Forms & Dimensional Ranges
Common reference product forms for 304 stainless steel: Sheet / Plate, Coil / Strip, Pipe / Tube, Bar.
| Finishes | No.1, 2B, BA, No.4, hairline, 8K mirror |
|---|---|
| Sheet / coil thickness | 0.3–6.0 mm |
| Plate thickness | 6–80 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
- Kitchen and catering equipment
- Food and beverage processing
- Architectural panels and trim
- Water tanks and plumbing
- General fabrication
304 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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304 Stainless Steel Round Bar
304/304L stainless steel round bar, in quotation-confirmed dimensions, bright drawn h9/h11 or peeled, cut to length — machining stock with full heat traceability.
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Frequently Asked Questions
Is 304 stainless steel magnetic?
In the annealed condition 304 is essentially non-magnetic. Cold working (bending, rolling, drawing) transforms some austenite to martensite, so heavily formed 304 parts can be weakly magnetic. This does not indicate a quality problem.
What is the difference between 304 and 316 stainless steel?
316 adds 2–3% molybdenum, which significantly improves resistance to chlorides and salt spray. For indoor, food-contact and general architectural use 304 is sufficient; for marine, coastal or chemical exposure 316/316L is the safer choice.
Is 304 stainless steel food safe?
Yes. 304 is the standard food-contact stainless steel worldwide, often labelled 18/8 or 18/10 on cookware. It does not leach in normal food-processing conditions and cleans easily.
304 Compared With Other Grades
Organizational author: Tsingshan (Shandong) Iron & Steel Co., Ltd..Review method, status and limitations.
Other stainless steel grades:
304L316316L201321310S4104302205202301309S316Ti347904L409L4204394414442507303317L254 SMO440C17-4 PH2304
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