201
Typical reasons to choose 201
- Household appliances
- Kitchen utensils
- Sinks in suitable mild environments
- Doors and window components
- Railroad cars
- High-strength formed sheet components
Stainless steel grade comparison
201 vs 309S Stainless Steel
Compare 201 and 309S stainless steel by chemistry, room-temperature strength, high-temperature capability, oxidation resistance, forming, welding, thermal properties, product forms and procurement priorities.
Quick answer:
choose 201 for high-strength formed components in mild
room-temperature service where lower nickel content and
work hardening are useful. Choose 309S when the component
must withstand furnace temperatures, hot oxidizing gases
or repeated elevated-temperature exposure approaching
1000°C in air.
The service-temperature difference behind the decision
201
EN 1.4372 · UNS S20100
- Structure Austenitic
- Typical Cr 16.1%
- Typical Ni 3.6%
- Typical Mn 6.6%
- Main role Strength + forming
309S
EN 1.4833 · UNS S30908
- Structure Austenitic
- Typical Cr 22.3%
- Typical Ni 12.3%
- Air service guide Up to 1000°C
- Main role Heat resistance
Typical chemistry basis: Outokumpu Core 201/4372 and Therma 309S/4833. Maximum temperature is a high-temperature design guide, not a universal allowable temperature for every atmosphere or load case.
M03 · Decision summary
201 or 309S stainless steel: which one should you specify?
These grades are both austenitic but are optimized for completely different duty. 201 is a low-nickel, high-strength forming grade. 309S contains substantially more chromium and nickel and is designed for high-temperature oxidation resistance and creep-controlled equipment.
| Decision factor | 201 stainless steel | 309S stainless steel |
|---|---|---|
| Room-temperature strength |
High proof and tensile strength with strong
work-hardening behavior.
Strength advantage |
Good austenitic strength but not selected primarily for maximum room-temperature strength. |
| High-temperature oxidation | Not designed as a dedicated heat-resistant grade. |
High Cr-Ni chemistry provides much greater
oxidation resistance for furnace service.
Clear advantage |
| Maximum air-service guidance | No comparable heat-resistant rating should be assumed for 201. |
Approximately 1000°C according to EN 10095 /
Outokumpu guidance, subject to atmosphere and load.
High temperature |
| Formed sheet components |
High strength, high elongation and strong
work hardening suit many formed products.
Preferred |
Cold formable, but its higher-alloy chemistry is usually justified by temperature rather than ordinary sheet-forming needs. |
| Furnace equipment | Not the intended service family. |
Commonly used for furnace equipment,
annealing boxes, thermowells and baffle plates.
Preferred |
| Welding | Weldable using suitable austenitic stainless procedures. | Good to very good weldability using appropriate heat-resistant stainless welding procedures. |
| Continuous 600–900°C exposure | Not a recommended basis for choosing 201. | High-temperature capable, but long exposure in this range can introduce phase-related embrittlement concerns. |
| Relative alloy cost |
Low nickel chemistry normally provides
a lower alloy-cost structure.
Cost advantage |
High chromium and nickel content normally carries a significant alloy premium. |
Selection rule:
do not pay for 309S unless heat resistance is actually needed,
and do not specify 201 where high-temperature oxidation,
creep or furnace atmosphere controls component life.
M04 · Technical data
201 vs 309S stainless steel properties
The grades are optimized for different service regimes. 201 room-temperature sheet data should not be compared as though it were a direct substitute for 309S high-temperature design data.
Typical chemical composition
Manufacturer typical values by mass. Use the applicable specification and MTC for acceptance.
| Element / feature | 201 / S20100 | 309S / S30908 | Selection significance | Basis |
|---|---|---|---|---|
| Carbon | 0.05% | Approx. 0.06% | 309S is the lower-carbon version of the 309 heat-resistant alloy family. | Typical mill data |
| Chromium | 16.1% | 22.3% | 309S contains substantially more chromium, which is important to high-temperature oxidation resistance. | Outokumpu typical chemistry |
| Nickel | 3.6% | 12.3% | The much higher nickel content helps stabilize the austenitic structure and supports high-temperature service. | Outokumpu typical chemistry |
| Manganese | 6.6% | Conventional heat-resistant alloy level | 201 uses manganese to replace part of the nickel used in standard Cr-Ni alloys. | Grade design |
| Nitrogen | 0.08% | Not a primary alloying feature | Nitrogen contributes to the high room-temperature strength of 201. | Typical mill data |
Room-temperature mechanical comparison
201 data is an EN cold-rolled flat-product reference. 309S values below are typical annealed manufacturer data. Product condition must be confirmed before design use.
| Property | 201 | 309S | Condition / warning | Selection effect |
|---|---|---|---|---|
| 0.2% proof strength | 350 MPa | Approx. 310 MPa typical | Different published manufacturer conditions | 201 retains a strong room-temperature strength case. |
| Tensile strength | 680–880 MPa | Approx. 600 MPa typical | Do not treat as identical specification conditions | 309S is selected for high-temperature performance rather than peak room-temperature strength. |
| Elongation | 45% | Approx. 51% typical | Annealed reference | Both remain ductile austenitic grades. |
| Work hardening | High | Austenitic work-hardening behavior | Fabrication-dependent | 201 is specifically notable for its high work-hardening coefficient. |
High-temperature properties and design indicators
309S values are from Outokumpu Therma high-temperature reference data. 201 is not presented as an equivalent heat-resistant grade.
| Property / condition | 201 | 309S | Reference condition | Interpretation |
|---|---|---|---|---|
| High-temperature grade | No | Yes | Product-family classification | 309S is designed specifically for heat resistance. |
| Maximum application temperature | Do not assign 309S-type rating | 1000°C | Air; EN 10095 guidance | Atmosphere, stress and thermal cycling can reduce the practical allowable temperature. |
| Rp0.2 at 600°C | Use project-specific approved data | Approx. 140 MPa minimum reference | Outokumpu / EN 10028-7 basis | Useful for elevated-temperature design screening. |
| 10,000 h creep rupture at 700°C | Not established here | Approx. 36 MPa mean reference | Outokumpu Therma data | Creep becomes a critical design property at high service temperatures. |
| Long exposure 600–900°C | Not intended as heat-resistant selection | Embrittlement risk must be considered | Continuous operation | High-temperature capability does not mean unlimited microstructural stability. |
Typical physical properties
Use these as reference values only; approved design data should control thermal calculations.
| Property | 201 | 309S | Condition | Selection effect |
|---|---|---|---|---|
| Density | 7.8 kg/dm³ | 7.8 kg/dm³ | 20°C reference | Essentially identical. |
| Elastic modulus | 200 GPa | 196 GPa | 20°C | Very similar room-temperature stiffness. |
| Thermal conductivity | 15 W/m·K | 15 W/m·K | 20°C | Same cited room-temperature value. |
| Thermal expansion | Verify for project calculation | 18.8 ×10⁻⁶/K | 20–600°C for 309S | High-temperature dimensional movement must be incorporated into 309S equipment design. |
| Electrical resistivity | 0.70 Ω·mm²/m | 0.87 Ω·mm²/m | 20°C | 309S has higher cited electrical resistivity. |
| Magnetizable | Normally no* | Austenitic / normally low response | Annealed reference | Cold work and weld structure can influence actual magnetic response. |
Do not use room-temperature strength alone:
201 can look very competitive in a tensile table,
but it does not provide the high-chromium/high-nickel
oxidation and creep-service design basis that makes 309S
relevant to furnace and hot-gas equipment.
M05 · Product form matrix
Product forms and supply routes for 201 and 309S
Both grades are available as flat products, but they serve different markets. 201 is primarily a strength/forming alloy, while 309S supply is commonly associated with high-temperature plate, sheet and furnace fabrication.
Availability note:
this matrix does not represent current inventory.
Confirm thickness, width, finish, quantity,
heat treatment and governing specification in the RFQ.
| Product form | 201 | 309S | Procurement note |
|---|---|---|---|
| Cold-rolled coil & sheet | Common | Available | Published product route for both grades. |
| Hot-rolled coil & sheet | Available | Available | Confirm heat-resistant grade surface and annealing condition. |
| Quarto plate | Verify source | Common route | 309S plate is relevant to furnace and hot equipment fabrication. |
| Precision strip | Available | Available | Confirm actual gauge and mill program. |
| Pipe / tube | Specification-dependent | Specialist route | Do not assume flat-product availability proves tubular availability. |
| Furnace fabricated parts | Not intended | Typical application | 309S is commonly selected for furnace internals and thermal equipment. |
| Decorative formed sheet | Relevant | Possible but costly | 309S alloy content is usually unnecessary without thermal duty. |
| High-temperature welded fabrication | Not intended | Relevant | Welding consumable and design temperature must match the service. |
M06 · Grade selector
Use service temperature to choose 201 or 309S
Check the conditions that actually control component life. For this comparison, temperature and atmosphere usually matter more than the grade number itself.
Preliminary result
Start with 201
For mild room-temperature service where strength, formability and lower nickel content matter, 201 is normally the more economical starting point.
Send Conditions to an Engineer
STEP 01
Define temperature
Normal, peak and continuous operating temperatures.
STEP 02
Define atmosphere
Air, combustion gas, sulfur, carbon, nitrogen, halogens or salts.
STEP 03
Define mechanical load
Room-temperature strength, creep, thermal fatigue and cycling.
STEP 04
Define fabrication
Sheet forming, welding, plate fabrication and heat treatment.
M08 · Applications & limitations
Where 201 works, where 309S earns its premium, and where neither should be selected blindly
The two materials overlap as austenitic stainless steels, but their normal applications are separated primarily by temperature rather than appearance or grade number.
309S
Typical reasons to choose 309S
- Furnace equipment
- Annealing boxes
- Thermowells
- Baffle plates
- Quenching-salt pots
- High-temperature valves and flanges
!
Conditions requiring additional alloy review
- Strong sulfur-containing hot gases
- Highly carburizing low-oxygen atmospheres
- Hot halogen / HCl environments
- Molten chloride or hydroxide salts
- Very high creep loads near maximum temperature
- Long service where room-temperature toughness after ageing matters
Why can 201 fail in furnace service?
201 is not alloyed as a dedicated heat-resistant grade.
At high temperature, oxidation rate, scale stability,
creep deformation and thermal cycling become controlling
failure mechanisms rather than room-temperature tensile strength.
Why can 309S still fail below 1000°C?
The quoted temperature is guidance for air service.
Sulfur compounds, halogens, molten salts, carburizing
atmospheres, high stress or severe cycling can reduce
the usable temperature substantially.
What happens during long 600–900°C exposure?
309S can develop phase precipitation during prolonged
exposure in this range, reducing room-temperature
toughness and ductility. Exposure time and maintenance
requirements should therefore be part of selection.
Does more chromium always mean better aqueous corrosion?
No. 309S is optimized primarily for high-temperature
oxidation performance, not as a universal wet-corrosion alloy.
Process chemistry must still be evaluated separately.
Important:
309S is a heat-resistant alloy, not simply an expensive
upgrade from 201. If the component never sees meaningful
high temperature, its extra chromium and nickel may provide
little economic benefit.
Material image comparison
Reserved positions for approved product imagery showing each material option. These blocks can be replaced directly with Media Library images later.
Reserved image position
Use an approved product-form or surface-detail image.
Reserved image position
Use an approved product-form or application image.
M10 · Standards & equivalence
201 and 309S stainless steel grade designations
The grades share an austenitic microstructure but are not equivalent materials. 309S belongs to a heat-resistant high Cr-Ni alloy family, while 201 belongs to the low-nickel Cr-Mn family.
| Designation system | 201 | 309S | Procurement note |
|---|---|---|---|
| ASTM / AISI type | 201 | 309S | Common North American type designations. |
| UNS | S20100 | S30908 | Use UNS where exact alloy identity is required. |
| EN material number | 1.4372 | 1.4833 | European designation references used on this page. |
| EN designation | Cr-Mn low-nickel family | X12CrNi23-13 | 309S is defined by its high Cr-Ni heat-resistant chemistry. |
| Microstructure | Austenitic | Austenitic | Same broad microstructure does not imply equivalent service capability. |
| Primary standards family | Corrosion-resistant flat-product standards | Heat-resistant / high-temperature standards | Design and acceptance standards differ by service and product form. |
ASTM A240/A240M
Common stainless sheet, strip and plate
specification reference.
EN 10088-2
Common flat-product property reference
for corrosion-resistant grades such as 201.
EN 10095
Heat-resistant steel reference associated
with elevated-temperature grades such as 309S.
EN 10028-7
Source basis used for selected elevated-temperature
mechanical-property references.
Do not approve a 201-to-309S substitution—or the reverse— from a designation table alone. Verify the product standard, service temperature, atmosphere, mechanical loading, heat treatment, dimensions and certificate requirements.
M11 · Direct answers
201 vs 309S stainless steel FAQ
Direct answers to the main purchasing and engineering questions behind the 201 versus 309S decision.
What is the main difference between 201 and 309S stainless steel?
201 is a low-nickel Cr-Mn austenitic stainless steel focused on high strength and formed products. 309S is a high-chromium, high-nickel austenitic heat-resistant grade designed primarily for elevated-temperature oxidation resistance.
Which is stronger at room temperature?
201 has a strong room-temperature strength advantage in common cold-rolled sheet conditions and also has a high work-hardening coefficient. 309S is not normally selected because it offers greater room-temperature strength.
Which is better at high temperature?
309S is the clear choice between these grades. Its much higher chromium and nickel content provides improved oxidation resistance, and published guidance lists approximately 1000°C as a maximum application temperature in air.
Can 201 be used in a furnace?
201 should not be treated as a direct furnace-material substitute for 309S. Furnace design requires consideration of oxidation, scale stability, creep, thermal fatigue, atmosphere and service time.
Is 309S suitable for continuous service at 1000°C?
The 1000°C figure is guidance for air exposure, not an automatic allowable design temperature. Continuous stress, creep, atmosphere chemistry, cyclic operation and required service life must also be evaluated.
Why can 309S become brittle after high-temperature service?
Long exposure in certain intermediate high-temperature ranges can allow undesirable phases to precipitate. Outokumpu notes a slight susceptibility to embrittlement for continuous service around 600–900°C.
Which grade costs more?
309S normally has the higher alloy cost because it contains substantially more chromium and nickel. 201 uses a low-nickel Cr-Mn chemistry partly to reduce dependence on nickel.
Can 309S replace 201 in a normal sheet-metal component?
It may be physically possible in some applications, but it is usually economically unnecessary if there is no elevated-temperature requirement. The extra alloy content of 309S should solve a real thermal or oxidation problem.
Is 309S better for every corrosive environment?
No. 309S is optimized primarily for high-temperature corrosion and oxidation resistance. Aqueous chloride, acid or process corrosion should be evaluated independently rather than assuming that higher chromium always makes 309S the best choice.
M13 · Sources & technical review
Technical basis for this 201 vs 309S comparison
The page separates room-temperature material properties from elevated-temperature design data and identifies atmosphere, exposure duration and creep as conditions that can reverse a simple grade recommendation.
Primary technical references
- Outokumpu Core Range Datasheet 201/4372 chemistry, mechanical properties, physical properties, applications and product forms.
- Outokumpu Core 201/4372 Product Information Low-nickel Cr-Mn chemistry, strength, work hardening and application guidance.
- Outokumpu Therma Range Datasheet 309S/4833 chemistry, oxidation resistance, elevated-temperature yield, creep properties, physical properties and fabrication guidance.
- Aperam 309S / 1.4833 Technical Data Independent manufacturer reference for 309S chemistry, room-temperature mechanical properties and heat-resistant applications.
- EN 10095 Heat-resistant steel reference used for high-temperature application guidance.
- EN 10028-7 Reference basis for selected high-temperature mechanical-property values.
Page accountability
Author
[Author name]
Add the real person responsible for the material-selection and procurement content.
Technical reviewer
[Technical reviewer name]
Add the real reviewer and relevant metallurgy, materials or high-temperature engineering credentials.
Review date
[Reviewed date]
Set only after the technical review has actually been completed.
Review scope
Chemistry · high temperature · creep · fabrication
Review should confirm the numeric values, product conditions and atmosphere-dependent temperature guidance before publication.
M14 · Ask an engineer
Still deciding between 201 and 309S?
Send the operating temperature, atmosphere, load and fabrication details so the material can be screened against both room-temperature requirements and high-temperature failure modes.
- 201, 309S or alternative grade under consideration
- Normal operating temperature
- Peak temperature and duration
- Continuous or cyclic temperature exposure
- Air, combustion gas, sulfur, carburizing or nitriding atmosphere
- Presence of halogens, salts or process deposits
- Required room-temperature strength
- Creep or sustained high-temperature loading
- Sheet, coil, plate, pipe, tube or fabricated component
- Thickness, dimensions and tolerances
- Welding and filler-metal requirements
- Applicable ASTM, EN or customer specification
- Quantity, destination, delivery date and MTC requirements
Send your material requirement
For high-temperature applications, include both temperature and atmosphere. A temperature alone is not enough to select a heat-resistant stainless steel.