Key takeaways: 304 coil at a glance
- Grade identity: 304 (UNS S30400, Werkstoff 1.4301) is the baseline 18-8 austenitic stainless steel, roughly 18% chromium, 8% nickel, with no molybdenum.
- Corrosion ceiling: its PREN is only ~18, the bottom of the pitting ladder. Excellent in dry, indoor, food and architectural service; not for chlorides.
- Coil form: this is the master mill coil / strip, the flat input that is slit to width, re-coiled, or cut down to 304 sheet. Available in 2B, BA, No.4 and No.1 finishes.
- Two limits to respect: chlorides or seawater → step up to 304 vs 316; as-welded heavy sections held at 425–815 °C → step down in carbon to 304L.
- Traceable supply: genuine mill coil with an EN 10204 3.1/3.2 mill test certificate provided with every order, ex-stock for immediate dispatch.
What is 304 stainless steel coil?
304 is the default grade of the austenitic stainless steel family, the "18-8" composition of ~18% chromium and ~8% nickel that makes the steel non-magnetic in the annealed condition and gives it the ductility that lets it be deep-drawn, pressed and roll-formed. The chromium forms a passive oxide film that self-repairs in air and mild aqueous media; the nickel stabilizes the austenite phase.
Coil is the master form. Flat stainless begins life as hot-rolled band, is cold-reduced, annealed and finished on a continuous line, then shipped as a coil. That coil is the input to everything downstream: it is slit into narrower strip, re-coiled, or cut-to-length into sheet. Specifying 304 in coil form, rather than pre-cut sheet, is what you do when you are feeding a slitting line, a press shop, a roll-former or a tube mill and want the material in its continuous, as-rolled state. For the full grade authority and the other forms, see the 304 grade hub; for how coil relates to flat-cut product, see sheet vs plate vs coil.
Chemical composition
304 coil is supplied to the UNS S30400 / ASTM A240 chemistry below (weight %, balance iron).
| Element | Symbol | Min % | Max % |
|---|---|---|---|
| Carbon | C | – | 0.08 |
| Chromium | Cr | 18.0 | 20.0 |
| Nickel | Ni | 8.0 | 10.5 |
| Manganese | Mn | – | 2.00 |
| Silicon | Si | – | 0.75 |
| Phosphorus | P | – | 0.045 |
| Sulfur | S | – | 0.030 |
| Nitrogen | N | – | 0.10 |
| Molybdenum | Mo | Not specified, see below | |
| Iron | Fe | Balance | |
Why no molybdenum (and what that costs you)
The single defining fact of 304 chemistry is the absence of deliberate molybdenum. Molybdenum is the element that buys chloride-pitting resistance; 316 adds 2–3% of it precisely for that reason. Because 304 has none, its pitting resistance equivalent number, PREN = Cr + 3.3·Mo + 16·N, reduces to essentially the chromium-plus-nitrogen term and lands at ~18. That number is the whole story of where 304 can and cannot go: it is the reason 304 is the economical choice for dry and mild service and the reason it must hand chloride duty to 316.
Mechanical properties
Minimum room-temperature properties for annealed 304 strip/coil per ASTM A240:
| Property | Minimum (annealed) |
|---|---|
| Tensile strength | ≥ 515 MPa (75 ksi) |
| Yield strength (0.2% offset) | ≥ 205 MPa (30 ksi) |
| Elongation (50 mm) | ≥ 40% |
| Hardness | ≤ 92 HRB / ≤ 201 HBW |
Cold-work tempers (¼-, ½- and full-hard strip)
304 work-hardens rapidly. Cold-rolled strip can be supplied in tempers, quarter-hard, half-hard and full-hard, that raise tensile and yield strength well above the annealed minimums while reducing elongation. Specify the temper when the part relies on spring-back or surface hardness; specify annealed when it must be deep-drawn or roll-formed. The same cold work that raises strength also makes the surface magnetic after cold work, even though annealed 304 is non-magnetic.
Physical properties
| Property | Typical value (annealed) |
|---|---|
| Density | 7.93–8.00 g/cm³ |
| Melting range | ~1400–1455 °C |
| Thermal conductivity (100 °C) | ~16.2 W/m·K |
| Mean coefficient of thermal expansion (0–100 °C) | ~17.3 µm/m·°C |
| Elastic modulus | ~193–200 GPa |
| Magnetic response | Non-magnetic (annealed); slightly magnetic after cold work |
The density figure is not academic for coil buyers, it is the number that drives the coil-weight calculation further down this page.
Corrosion behavior & PREN: what 304 coil resists and what it doesn't
This is where 304 is specified correctly or incorrectly. 304 resists general atmospheric corrosion, potable water, many organic acids, foodstuffs and most dry indoor environments. It is susceptible to three mechanisms that every specifier should recognize before choosing it.
Pitting & PREN ~18
With no molybdenum, 304 carries a PREN of only ~18 and sits at the bottom of the pitting ladder: 304 (~18) < 316 (~24) < 904L (~34) < Duplex 2205 (~35). In chloride-bearing water, seawater, de-icing salts, coastal air, chlorinated process streams, it is prone to pitting corrosion. The practical rule: if free chlorides are present, 304 is the wrong grade.
Chloride stress-corrosion cracking
Like all austenitic grades, 304 is susceptible to chloride stress-corrosion cracking, sudden, branching cracks under the combination of tensile stress, chlorides and warm temperatures (typically above ~50–60 °C). Molybdenum does not cure this; it is a family trait of the austenitics, and it is why hot chloride service moves beyond standard grades entirely.
Intergranular corrosion & the 304L answer
Standard-carbon 304 (C ≤ 0.08%) can sensitize: held in the 425–815 °C range, most commonly in the heat-affected zone of a weld, chromium combines with carbon to precipitate chromium carbides at the grain boundaries, locally depleting chromium and leaving the steel open to intergranular corrosion (sensitization). The fix is the low-carbon sibling: specify 304L (C ≤ 0.03%) for welded fabrications, or solution-anneal after welding. See 304 vs 304L for the full decision.
Equivalent grades & designations
| System | Designation |
|---|---|
| UNS | S30400 |
| Werkstoff (W.-Nr.) | 1.4301 |
| EN name | X5CrNi18-10 |
| JIS | SUS 304 |
| BS | 304S31 |
| AISI / common | 304 / 18-8 |
For a full cross-walk between systems, see the UNS / Werkstoff / JIS cross-reference.
304 coil vs the alternatives: when to choose it
vs 316: the chloride decision
316 adds 2–3% molybdenum, lifting its PREN to ~24 and giving it the chloride-pitting resistance 304 lacks. Choose 304 for dry, indoor, food and architectural duty where it is the economical choice; choose 316 the moment chlorides, seawater or marine air enter the service. This is the single most common 304 specification error, see 304 vs 316.
vs 304L: the sensitization decision
304 and 304L share the same corrosion ceiling; the difference is carbon. 304L caps carbon at ≤0.03% so the weld heat-affected zone does not sensitize, at a small cost in strength. Choose 304L for welded fabrications that cannot be post-weld annealed, see 304 vs 304L.
vs 430 and 201/202: the cost-down substitutes
| Grade | What changes | Why not (vs 304) |
|---|---|---|
| 430 | Ferritic, ~16–18% Cr, no nickel | Lower corrosion resistance and formability; magnetic; not a true 304 substitute for deep-draw or hygienic work. |
| 201 / 202 | Manganese and nitrogen substituted for part of the nickel | Cheaper when nickel is costly, but lower corrosion resistance and work-hardens even faster; verify suitability before substituting. |
Coil finishes
Finish is the primary coil decision, it sets both appearance and the base condition for any downstream polishing. Nandini Steel supplies 304 coil in the four workhorse finishes below.
| Finish | Process | Appearance | Typical use |
|---|---|---|---|
| 2B | Cold-rolled, annealed, pickled, skin-passed | Smooth, uniform, lightly reflective | The default coil finish; general fabrication, appliances, food equipment |
| BA (bright annealed) | Cold-rolled, bright-annealed in protective atmosphere | Mirror-bright, highly reflective | Pre-polish base, decorative and reflective panels |
| No.4 | Mechanically brushed / abraded | Satin, directional grain | Architectural cladding, kitchen and hygienic surfaces |
| No.1 / HRAP | Hot-rolled, annealed, pickled | Dull, matte, rough | Heavy-gauge coil for industrial and structural fabrication |
Common finish-selection mistake
A recurring error from the stockyard: ordering 2B and then discovering the part needs a mirror polish. If the end result must be bright or polished, start from BA, polishing up from a 2B surface adds cost and time. Confirm the final surface requirement before the coil finish is locked. For the full breakdown, see stainless steel finishes: 2B, BA, No.4.
Forms, dimensions & slitting
304 coil is held as both cold-rolled (CR) and hot-rolled (HR) master coil and slit to the width a job needs. Cold-rolled coil covers the thinner gauges and the 2B/BA/No.4 finishes; hot-rolled annealed-pickled (No.1) coil covers the heavier gauges. Coil is supplied on standard inner diameters for mill handling, master-coil or slit, and can be cut down to strip or sheet.
Because dimensional availability moves with stock, the exact thickness, width and slit-width ranges held at any time are confirmed on inquiry, request current stock and tolerances with your RFQ.
Other 304 forms
Need flat-cut product rather than coil? See 304 sheet and 304 plate, or the full 304 grade hub.
Coil weight & how to calculate
Coil weight follows directly from the dimensions and the density of 304 (7.93 g/cm³). For a flat strip, weight per running meter is:
kg per meter = thickness (mm) × width (mm) × 7.93 ÷ 1000
Worked example, a 1.2 mm × 1250 mm coil:
- Multiply thickness by width: 1.2 × 1250 = 1500 mm².
- Multiply by density and divide by 1000: 1500 × 7.93 ÷ 1000 = 11.9 kg per meter.
- Multiply by coil length to get the full coil mass, e.g. a 500 m coil ≈ 5,950 kg.
To run your own dimensions, use the weight calculator.
Standards & specifications complied
304 coil is supplied to the recognized flat-product standards:
- ASTM A240, chromium and chromium-nickel stainless steel plate, sheet and strip for pressure vessels and general application (the primary specification for 304 flat product).
- ASME SA-240, the ASME Boiler & Pressure Vessel Code adoption of A240.
- ASTM A480, general requirements and dimensional tolerances for flat-rolled stainless.
- EN 10088-2, the European standard for stainless flat product for general use.
Testing, inspection & certification
Every 304 coil is shipped with an EN 10204 3.1/3.2 mill test certificate provided with every order, giving the heat/cast chemistry and mechanical results traceable to the melt. For welded and corrosion-critical work, intergranular-corrosion testing per ASTM A262 confirms the material is not sensitized, and PMI (positive material identification) verifies grade at receiving. Surface and thickness inspection confirm the coil meets the ordered finish and tolerance. Learn more about EN 10204 3.1 mill test certificate levels and how we handle testing, MTC, NDT and PMI.
Applications of 304 coil by industry
304 coil is the baseline flat product across general fabrication, architecture and hygienic industries:
- Food & dairy processing, tanks, hoppers, conveyors and panels in clean, non-chloride environments.
- Architectural & cladding, facades, trims, handrails and interior panels, usually in BA or No.4 finish.
- General fabrication, enclosures, appliances, pressed and roll-formed components, tube and pipe stock.
The boundary is chlorides: for marine, coastal or salt-water exposure, 304 pits, specify 316 instead.
Welding & fabrication of 304 coil
304 is readily welded by TIG, MIG and resistance methods. The matching filler is ER308L, a low-carbon austenitic consumable whose weld metal resists heat-affected-zone sensitization. For welded sections that will sit in the 425–815 °C range without post-weld annealing, specify 304L to keep the HAZ corrosion-resistant. 304 forms and deep-draws well but work-hardens quickly, so it is "gummy" to machine and benefits from sharp tooling, positive feeds and interstage annealing on severe draws. See weld decay and filler selection and heat treatment / solution annealing (solution anneal ~1010–1120 °C followed by rapid quench).
Pricing & how we quote
304 coil is a commodity flat product whose price tracks the nickel surcharge and the LME daily, so we do not publish fixed price tables. We quote live against your exact finish, gauge, slit width and quantity. All stock is ex-stock and available for immediate dispatch; send your specification for a current quotation by RFQ or WhatsApp +91 99202 09184.
FAQ
Is 304 coil magnetic?
Does 304 coil rust?
304 coil vs 316 coil, which should I choose?
What finishes does 304 coil come in?
How do I calculate 304 coil weight?
Can you slit 304 coil to width and supply a mill test certificate?
Request a quote for 304 stainless steel coil
Nandini Steel is an ISO 9001:2015-certified stockist and supplier, established in 2003, with 307+ projects delivered for 260+ clients across 36+ export countries over 20+ years. We hold genuine mill 304 coil ex-stock for immediate dispatch, slit to width, in 2B, BA, No.4 and No.1 finishes, every order shipped with an EN 10204 3.1/3.2 mill test certificate.
- Phone: +91 22 43404600 · +91 9920209184
- WhatsApp: +91 99202 09184
- Email: reachus@nandinisteel.com
- Address: 25, Dreamland Building, 601, 6th Floor, Mama Parmanand Marg, Charni Road, Opera House, Girgaon, Mumbai, Maharashtra 400004, India
- GSTIN: 27ADJPA7240C1Z0
Send your finish, gauge, slit width and quantity for live pricing, request an RFQ.
Related grades to cross-shop
Part of our steel coil range and all stainless steel coil grades.