304L Stainless Steel (UNS S30403)
Austenitic (low carbon) · ASTM A240/A240M · Density 7.93 g/cm³
Type 304L (UNS S30403 / EN 1.4307) is the low-carbon chromium-nickel austenitic paired with 304 for sheet, coil, plate, pipe, tube and bar when welded assemblies will remain as-welded. Carbon is limited to ≤0.030% to reduce sensitization (intergranular corrosion) risk in the heat-affected zone versus standard 304 (≤0.08%). It keeps the 304-family corrosion profile — not a molybdenum upgrade like 316/316L — and dual 304/304L certification is valid only when the heat and MTC meet both chemistry and strength rules.
Quotation brief
Quote 304L When
Quote 304L when the RFQ names sheet, coil, plate, pipe, tube or bar in the 304 corrosion family, and welded assemblies will remain as-welded so sensitization (intergranular corrosion) risk in the heat-affected zone matters. Low carbon (≤0.030%) is the reason to prefer 304L over standard 304 — it does not raise chloride pitting resistance the way molybdenum-bearing 316/316L does. Annealed flat product under ASTM A240 is the usual starting condition; dual 304/304L chemistry, sanitary-adjacent cleaning duty and non-flat product standards must be ordered explicitly. Treat 304L as the welding-focused 304 sibling, not a universal food or marine grade and not the owner of a dedicated 304-vs-304L compare URL.
Best fit
- As-welded tanks, process pipe, tube and structural weldments that will not receive a full post-weld solution anneal.
- Annealed sheet, coil and plate orders that need 304-family formability with the low-carbon HAZ limit written on the purchase order.
- Cleanable food or general process equipment where molybdenum alloying is not justified after chloride and cleaning-chemistry review.
Limits to check
- Warm chlorides, coastal salt, brine and aggressive chemical cleaning still call for 316/316L or a higher alloy — 304L is not a pitting upgrade.
- Annealed A240 strength minima are slightly lower than 304; dual certification is valid only when the MTC proves both chemistry and strength.
- A flat-product A240 summary does not define pipe, tube, bar or sanitary fitting acceptance; name the governing product standard and documents.
Quoted product forms
Quoted product forms for 304L Stainless Steel (UNS S30403)
We quote 304L Stainless Steel as sheet / plate, coil / strip, pipe / tube, bar against the named product standard.
- Traceability: heat or lot identity plus the inspection document named in the RFQ (EN 10204 3.1 when that route supports it).
- Processing: decoiling, cutting, polishing, shearing and beveling as ordered.
- Next step: send product form, size and quantity; we quote the supply route.
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.
Properties by Condition
304L Annealed (standard flat-product supply)
The usual mill condition for ASTM A240 sheet, plate, coil and strip — maximum ductility for forming before intentional cold work, with the low-carbon limit retained for welded assemblies.
| Tensile strength | ≥485 MPa (70 ksi) |
|---|---|
| Yield strength (0.2%) | ≥170 MPa (25 ksi) |
| Elongation | ≥40% |
| Hardness | ≤201 HBW |
Dual-certified 304/304L (when ordered and proven on MTC)
Market practice often supplies heats that meet 304L carbon (≤0.030%) and 304 annealed strength minima together. Accept only when the purchase order and heat-specific MTC demonstrate both chemistry and mechanical rules for the ordered product standard.
| Carbon | ≤0.030% (304L limit) |
|---|---|
| Tensile / yield | Must also meet the applicable 304 minima named on the order |
| Ordering note | Write dual 304/304L explicitly; do not infer from a grade stamp alone |
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
- 304L shares the general chromium-nickel corrosion scope of the 304 family for atmospheric, indoor and many process duties; lower carbon reduces sensitization risk in suitable welded construction but does not increase chloride pitting resistance versus 304.
- Against molybdenum-bearing 316/316L, 304L remains the wrong default for warm chlorides, coastal salt deposits, brine or aggressive chemical cleaning — upgrade the alloy family when those exposures dominate rather than relying on the L-grade carbon limit.
- Review chlorides, temperature, pH, deposits, crevices, drainage, cleaning chemistry, weld heat tint and surface finish for the actual as-welded component. A grade designation alone is not a service-life guarantee.
Fabrication & Heat Treatment
| Welding | Generally weldable with a qualified austenitic procedure, matching or over-alloyed filler where required, controlled heat input, purge on tubular joints and heat-tint removal when corrosion service demands it. The ≤0.030% carbon limit reduces sensitization (IGC) risk in the HAZ for as-welded tanks, pipe and structural weldments, but it does not qualify the WPS, filler or surface restoration — and it is not a substitute for 316L in chloride pitting service. |
|---|---|
| Forming | Annealed 304L sheet and strip draw and bend well, but the alloy work-hardens during forming — tooling load, springback, bend direction, draw ratio and any intermediate anneal must be proven on the actual gauge and reduction route. |
| Machining | Use rigid tooling, positive feeds and controlled cutting heat to avoid a work-hardened surface; qualify the route on the delivered condition. Free-machining sulfur grades require separate corrosion and welding review. |
| Heat treatment | Solution annealing with rapid cooling restores the intended annealed austenitic condition after suitable cold work or fabrication where applicable. Conventional quench-and-temper treatment does not through-harden austenitic 304L; do not rely on post-weld anneal unless the project actually schedules it. |
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, 304 / UNS S30400 / EN 1.4301 (standard-carbon sibling — not automatic substitute; dual cert only when MTC proves both) in the Related 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 |
| Related | 304 / UNS S30400 / EN 1.4301 (standard-carbon sibling — not automatic substitute; dual cert only when MTC proves both) |
Ordering Checks for 304L
- State UNS S30403 or EN 1.4307, product form (sheet/coil/plate/pipe/tube/bar), ASTM A240 or the governing standard edition, thickness or size, finish and annealed condition.
- Define as-welded vs post-weld annealed service, chlorides, cleaning chemicals and whether 304 or 316/316L is the correct alloy family before locking 304L.
- Specify any dual 304/304L requirement explicitly, plus finish (2B, BA, No.4, etc.), critical face, heat-tint removal and passivation expectations.
- Request heat-specific MTC / EN 10204 3.1, destination port, packing method and lot traceability — see PMI and purchase-order wording guides when writing the document list.
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, hairline, 8K mirror |
|---|---|
| Sheet / coil thickness | 0.3–6.0 mm |
| Plate thickness | 6–60 mm |
| Pipe / tube / bar | Quoted to the governing product standard (for example ASTM A312, A554 or A276) with size, schedule or diameter named in the RFQ |
Common surface and delivery options
- No.1, 2B, BA or mechanically polished finish when supported by the product route
- Annealed and pickled coil/strip, or polished tube finish as specified
- Protective film, critical face and agreed surface sample for visible architectural or food-contact parts
- 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. Send the required product form, dimensions, condition and finish; we quote the matching supply route.
Browse related product hubs:Sheet & plate,Coil & strip,Pipe & tube,Bar & rod.
Typical Applications
- Welded tanks, vessels and structural weldments left as-welded
- Process and utility piping where low-carbon HAZ resistance is specified
- Food and beverage equipment with validated cleaning chemistry (when molybdenum upgrade is not justified)
- Heat exchangers and general fabrication sheet, coil, pipe and tube
- Cleanable process components adjacent to sanitary duty after chloride and cleaning review
304L Products We Export
304 Stainless Steel Sheet
304/304L ASTM A240 sheet in 2B, BA, No.4 and mirror. Common inquiry range 0.3–6.0 mm, 1000/1219/1500 mm widths, cut to size with quoted documents.
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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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304L Compared With Other Grades
Related buyer guides:
Frequently Asked Questions
What are 304L stainless steel properties for sheet and plate?
For annealed flat product summarized under ASTM A240/A240M, Type 304L (UNS S30403) typically lists minimum tensile ≥485 MPa (70 ksi), 0.2% yield ≥170 MPa (25 ksi) and elongation ≥40%, with hardness capped around ≤201 HBW. Carbon is limited to ≤0.030%. These are room-temperature engineering minima for the annealed condition — product form, thickness and tubular or bar standards change the requirement. Confirm chemistry, tensile results and the contracted edition on the MTC before approval.
What is the difference between 304 and 304L stainless steel?
The practical difference is carbon: ≤0.08% for 304 versus ≤0.030% for 304L. Lower carbon reduces chromium carbide precipitation (sensitization) risk in weld heat-affected zones, so 304L better preserves intergranular corrosion resistance after welding when the assembly remains as-welded without a full post-weld solution anneal. 304L annealed A240 minima are slightly lower in strength than 304. Dual 304/304L is valid only when one heat meets both chemistry and strength rules. Use the 304 grade page for general fabrication context and the site 304 vs 304L welding buyer guide for the weld and certificate checklist — this grade page does not replace a dedicated compare URL.
When should I choose 304L instead of 316L?
Choose 304L when the corrosion profile of the 304 alloy family is adequate and the driver is low-carbon welding / as-welded HAZ resistance rather than chloride pitting. Specify 316/316L (molybdenum-bearing) when warm chlorides, coastal salt, brine, aggressive chemical cleaning or marine-adjacent duty dominate. 304L does not raise pitting resistance the way 316L does; do not substitute 304L for 316L on chloride service alone. Food or cleanable process equipment can use 304L after cleaning chemistry and chloride review — reserve pharmaceutical or sanitary chloride-heavy duty for the molybdenum grade when the project requires it.
How do EN 1.4307 and 304L sheet/pipe/bar orders relate?
EN 1.4307 (X2CrNi18-9) is the common European designation paired with ASTM/UNS Type 304L (S30403). Naming 1.4307, SUS304L or 304Lss-style shorthand does not replace the product standard: sheet and plate usually follow ASTM A240 (with A480 ordering/finish context), welded or seamless pipe follow standards such as A312, mechanical tube A554, and bar A276 or the project code. State form, size, finish (2B, BA, No.4, etc.), low-carbon requirement, dual-cert rules if any, and inspection documents (for example EN 10204 3.1) in the RFQ — a grade label alone is not a complete order.
Published by Tsingshan (Shandong) Iron & Steel Co., Ltd..Sources, update policy and technical limitations.
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