304
Typical reasons to choose 304
Kitchen equipment, general process fabrication, formed sheet and atmospheric service.
Stainless steel grade comparison
304 vs 316L Stainless Steel
Compare 304 and 316L stainless steel by chemistry, microstructure, corrosion resistance, fabrication, product form, governing standard and procurement priorities.
Quick answer: Choose 304 for general corrosion resistance and broad-purpose fabricated service. Choose 316L when chlorides, more aggressive process conditions or low-carbon welded corrosion performance define the purchase requirement.
The alloying and microstructure difference behind the selection decision
304
EN 1.4301 · UNS S30400- C0.04%
- Cr18.1%
- Ni8.1%
- Mo—
316L
EN 1.4404 · UNS S31603- C0.02%
- Cr17.2%
- Ni10.1%
- Mo2.1%
Technical basis: Outokumpu Core 304/4301 and Supra 316L/4404 reference material. Final composition and properties must follow the applicable specification and mill test certificate.
M03 · Decision summary
304 or 316L: which one should you specify?
The change to 316L adds molybdenum and lowers carbon. Both effects must be assessed against service exposure, weld design and material condition.
| Decision factor | 304 stainless steel | 316L stainless steel | |
|---|---|---|---|
| Corrosion resistance | 304 — Austenitic Cr-Ni | 316L — Low-carbon austenitic Cr-Ni-Mo | Service environment controls the decision. |
| Welding and fabrication | State thickness, weld route and required corrosion performance. | State thickness, weld route and required corrosion performance. | Do not use grade name alone. |
| Magnetic behavior | Confirm delivery condition and cold-work exposure. | Confirm delivery condition and cold-work exposure. | Microstructure can matter to the design. |
| Supply condition | Define product form, finish, dimensions and certificate scope. | Define product form, finish, dimensions and certificate scope. | Quote to the finished requirement. |
| Selection priority | Kitchen equipment, general process fabrication, formed sheet and atmospheric service. | Welded process equipment, chloride-bearing environments and fabrication where low-carbon Mo-alloyed material is justified. | Start from service evidence, not price alone. |
316L offers more margin than 304, but severe seawater and stagnant chloride conditions can still require duplex or higher-alloy stainless steel.
M04 · Technical data
304 vs 316L Stainless Steel properties
Typical chemistry is shown as an engineering reference. Mechanical properties must be compared only under the same product standard and delivery condition.
Typical chemical composition
Reference values by mass, not guaranteed purchase limits.
| Element / indicator | 304 | 316L | Selection significance |
|---|---|---|---|
| C | 0.04% | 0.02% | Confirm final chemistry against the governing material standard and MTC. |
| Cr | 18.1% | 17.2% | Confirm final chemistry against the governing material standard and MTC. |
| Ni | 8.1% | 10.1% | Confirm final chemistry against the governing material standard and MTC. |
| Mo | — | 2.1% | Molybdenum materially changes localized-corrosion performance. |
Material and fabrication behavior
Use these points to frame a condition-specific technical review.
| Property | 304 | 316L | Procurement interpretation |
|---|---|---|---|
| Microstructure | Austenitic Cr-Ni | Low-carbon austenitic Cr-Ni-Mo | Defines the main fabrication and service behavior. |
| Heat treatment | Specify delivery condition; this comparison does not imply a hardening route. | Specify delivery condition; this comparison does not imply a hardening route. | Confirm finished property requirements. |
| General fabrication | Use the applicable welding/forming procedure. | Use the applicable welding/forming procedure. | Process route matters as much as grade. |
| Corrosion review | Define chlorides, chemicals, temperature, deposits and crevices. | Define chlorides, chemicals, temperature, deposits and crevices. | Higher-alloy review may be required. |
Engineering caution: 316L offers more margin than 304, but severe seawater and stagnant chloride conditions can still require duplex or higher-alloy stainless steel.
M05 · Product form matrix
Product forms and supply routes for 304 and 316L
Both grades can be supplied in common stainless product forms, but availability, finish and certification are product-specific. Confirm the exact grade and delivery condition in the RFQ.
RFQ rule: grade, product form, dimensions, tolerance, finish, governing standard, quantity, destination and certificate scope.
| Product form / route | 304 | 316L | Procurement note |
|---|---|---|---|
| Cold-rolled coil, strip and sheet | Common route | Common route | Confirm thickness, width, finish and edge. |
| Plate and fabricated components | Available | Available | State fabrication and inspection requirements. |
| Bar / mechanical component | Program dependent | Program dependent | Use the correct long-product standard and condition. |
| Welded fabrication | Procedure review | Procedure review | State joint design, filler, post-weld treatment and service. |
M06 · Grade selector
Screen 304 and 316L against the service conditions
This is a preliminary routing tool, not a substitute for governing specification review.
Preliminary result
Define the controlling requirement
Select the conditions that apply to your component.
Send conditions to an engineer01Define environment
02Define fabrication
03Define final condition
04Confirm standard
M08 · Applications & limitations
Where 304 works, where 316L is justified, and where a further review is needed
The relevant choice is the one that meets the finished-component and service requirement with defined specification evidence.
316L
Typical reasons to choose 316L
Welded process equipment, chloride-bearing environments and fabrication where low-carbon Mo-alloyed material is justified.
Review
Conditions needing a different alloy review
316L offers more margin than 304, but severe seawater and stagnant chloride conditions can still require duplex or higher-alloy stainless steel.
Fabrication and service comparison
Use these points to define the RFQ.
| Requirement | 304 | 316L | Selection effect |
|---|---|---|---|
| Corrosion resistance | 304 — Austenitic Cr-Ni | 316L — Low-carbon austenitic Cr-Ni-Mo | Service environment controls the decision. |
| Welding and fabrication | State thickness, weld route and required corrosion performance. | State thickness, weld route and required corrosion performance. | Do not use grade name alone. |
| Magnetic behavior | Confirm delivery condition and cold-work exposure. | Confirm delivery condition and cold-work exposure. | Microstructure can matter to the design. |
| Supply condition | Define product form, finish, dimensions and certificate scope. | Define product form, finish, dimensions and certificate scope. | Quote to the finished requirement. |
| Selection priority | Kitchen equipment, general process fabrication, formed sheet and atmospheric service. | Welded process equipment, chloride-bearing environments and fabrication where low-carbon Mo-alloyed material is justified. | Start from service evidence, not price alone. |
Important: 316L offers more margin than 304, but severe seawater and stagnant chloride conditions can still require duplex or higher-alloy stainless steel.
Material image comparison
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M10 · Standards & equivalence
304 and 316L stainless steel grade designations
304 and 316L are austenitic grades with different corrosion margins. Confirm the product form, delivery condition and governing standard before purchase.
| Designation / standard | 304 | 316L | Procurement caveat |
|---|---|---|---|
| ASTM / AISI type | 304 | 316L | Use the exact grade identity. |
| UNS | S30400 | S31603 | Use UNS where grade identity matters. |
| EN material number | 1.4301 | 1.4404 | Do not rely on informal equivalence alone. |
| Alloy family | Austenitic Cr-Ni | Low-carbon austenitic Cr-Ni-Mo | Molybdenum and carbon limit affect service selection. |
| Typical product route | A240 / A276 as applicable | A240 / A276 as applicable | Confirm dimensions, finish and delivery condition. |
| EN grade name | X5CrNi18-10 | X2CrNiMo17-12-2 | 304 and low-carbon 316L have different alloying and weld-sensitization considerations. |
| JIS reference | SUS304 | SUS316L | Confirm the governing JIS product standard and exact chemistry. |
| ASTM / ASME flat-product route | ASTM A240 / ASME SA-240 where applicable | ASTM A240 / ASME SA-240 where applicable | Confirm thickness range, finish and current edition. |
| ASTM long-product route | ASTM A276 / A479 as applicable | ASTM A276 / A479 as applicable | Bar, billet, forging and pressure-service requirements are product-specific. |
| EN flat-product reference | EN 10088-2 where applicable | EN 10088-2 where applicable | Use the exact delivery condition and product form. |
| EN long-product reference | EN 10088-3 where applicable | EN 10088-3 where applicable | Long-product properties must be checked separately from flat-product data. |
| Material certificate | EN 10204 3.1 when specified | EN 10204 3.1 when specified | State certificate, testing and traceability requirements in the RFQ. |
| Delivery condition | 304: commonly solution annealed; state finish and dimensions. | 316L: commonly solution annealed; state finish and dimensions. | Do not assume a common condition across forms, dimensions or suppliers. |
| Selection input | State chloride exposure, welded fabrication and required certificate level. | Use the governing specification for final acceptance. | |
304 · S30400Austenitic Cr-Ni stainless steel.
304 · 1.4301Common EN 304 material designation.
316L · S31603Low-carbon molybdenum-bearing austenitic grade.
316L · 1.4404EN low-carbon Cr-Ni-Mo designation.
Grade equivalence is not permission to substitute. Confirm chemistry, product form, dimensions, finish, delivery condition, standard revision and mill test certificate before changing material.
M11 · Direct answers
304 vs 316L Stainless Steel FAQ
Answers to the main purchasing and engineering questions behind this comparison.
What is the main difference between 304 and 316L stainless steel?
The change to 316L adds molybdenum and lowers carbon. Both effects must be assessed against service exposure, weld design and material condition.
Which grade has the stronger corrosion-resistance starting point?
316L has the higher localized-corrosion margin because it contains molybdenum, and its lower carbon content is useful where welded corrosion performance is a concern.
What should be included in an RFQ for this comparison?
State grade, product form, dimensions, finish, standard, quantity, service environment, weld route and required certificate or inspection level.
Can one grade replace the other simply to reduce cost?
No. A grade change can alter corrosion resistance, fabrication behavior, magnetic response, heat treatment and certification requirements. Compare the finished component and actual service.
When should a higher-alloy stainless steel be reviewed?
316L offers more margin than 304, but severe seawater and stagnant chloride conditions can still require duplex or higher-alloy stainless steel.
M13 · Sources & technical review
Technical basis for this 304 vs 316L comparison
This page distinguishes manufacturer typical chemistry from final purchase specification. It does not make a live-inventory or fixed-price claim.
Primary technical references
- Outokumpu product-range informationOutokumpu Core 304/4301 and Supra 316L/4404 reference material.
- ASTM A240/A240MCommon flat-product specification family; confirm the applicable edition and delivery condition.
- EN 10088 seriesEuropean stainless-steel designation and product-condition reference.
- Mill test certificateFinal chemistry and properties must be confirmed against the supplied heat and purchase specification.
Page accountability
AuthorStainless Steel Market technical content team
Material-selection and procurement guidance for buyer review.
Technical reviewSupplier confirmation required for final acceptance
Confirm product form, standard, condition and MTC for each enquiry.
Review date24 September 2026
Checked against current manufacturer reference material.
Update log
2026-09-24 — Initial T09 comparison prepared with technical tables, selector, FAQ and RFQ routing.
M14 · Ask an engineer
Still deciding between 304 and 316L?
Send the product form, service environment, fabrication route, dimensions and governing specification for a condition-specific material review.
- 304, 316L or alternative grade under consideration
- Product form, dimensions, tolerance and finish
- Chlorides, chemicals, temperature and cleaning conditions
- Welding, forming, machining and final condition
- Required standard, MTC, inspection and destination
- Quantity, timing and commercial requirements
Send your material requirement
For a useful review, include product form, dimensions, service conditions, fabrication route, required standard, quantity and documentation needs.