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Grade 309S, heat-resistant austenitic stainless steel

309S Stainless Steel Coil and Sheet

A low-carbon version of 309, with about 23% chromium and 13% nickel. It resists oxidation up to about 1000–1100 °C and is easy to weld, for furnace parts, boilers and other welded structures in high-temperature service.
Tell us about your projectSee sizes
Forms
Coil, sheet
Thickness
0.15–3.0 mm
Width
1000 / 1219 / 1240 / 1500 mm
Also known as
UNS S30908, EN 1.4833, SUS309S

Is Sanmei Metal the right supplier for you?

We supply stainless steel together with the processing and technical support that projects and products need.

A good fit if you

Need a specific grade, finish or size for a project, from samples or one coil to a few containers
Want it slit, cut to size or fabricated to your drawing
Need documents: a Mill Test Report with every order, SGS testing on request
Want help choosing the right grade and finish for your application
Build products or projects: equipment housings, architectural interiors, elevator and kitchen work

When buying direct from a mill may suit you better

You need standard grades in full-mill quantities and compare on price per tonne
Not sure which applies to you? Tell us about your order and we will give you our professional advice.
Tell us about your projectSee what we fabricate

Sizes we supply in 309S.

Standard widths from stock, cut-to-length sheet, and custom slitting for strip-fed production lines.

309S coil

Width
1000, 1219, 1240, 1500 mm, or slit to your width
Thickness
0.15–3.0 mm
Coil weight
3–10 t

309S sheet

Width
1000, 1219, 1240, 1500 mm, or cut to size
Length
2000, 2438, 2500, 3000, 3048 mm
Thickness
0.3–3.0 mm
Every order ships with a Mill Test Report. Sample sheets and small batches are welcome. Standard mill finish: 2B finish.
Get a quote for 309SSend a cut list or drawing

Why choose 309S stainless steel?

Lower carbon than 309, so welded structures resist intergranular corrosion.

High heat resistance

Resists oxidation and carburization, up to about 980 °C in repeated heating and about 1000–1100 °C in continuous service.

Corrosion resistance

Better corrosion and heat resistance than 304, from its higher chromium and nickel.

Strength at temperature

Keeps its strength and toughness at high temperature, for heat exchangers and furnace components.

Weldable and formable

Low carbon limits carbide precipitation next to welds. Good formability for complex shapes.

Equivalents

ASTM / AISI

309S

UNS

S30908

JIS

SUS309S

EN / DIN

1.4833, X12CrNi23-13
Tell us what the part is, where it will be used and roughly how many. We confirm the grade and finish before you order.
Tell us your application

309S mechanical and physical properties.

Minimum mechanical values (ASTM A240) and typical physical values for annealed 309S.

Mechanical properties

Property
US
Metric
Yield strength, min.
30 ksi
205 MPa
Tensile strength, min.
75 ksi
515 MPa
Elongation, min.
40%
40%
Hardness, max.
95 HRB
217 HBW

Physical properties

Property
Value
Density
7.98 g/cm³
Melting range
1397–1453 °C
Specific heat, 0–100 °C
500 J/kg·K
Thermal conductivity
15.5 W/m·K at 100 °C; 18.6 W/m·K at 500 °C
Thermal expansion
14.9 µm/m·°C at 0–100 °C; 18.0 µm/m·°C at 0–500 °C
Electrical resistivity, 20 °C
78 µΩ·cm
Modulus of elasticity, 20 °C
193 GPa

Chemical composition, % by weight, max. unless a range (ASTM A240)

Grade
C
Mn
Si
P
S
Cr
Ni
309S
0.08
2.00
0.75
0.045
0.030
22.0–24.0
12.0–15.0
Tell us what the part is, where it will be used and roughly how many. We confirm the grade and finish before you order.
Tell us your application

Corrosion, heat and the shop floor.

How 309S behaves in service and in fabrication.

Corrosion resistance

Good in most environments, better than 304, from 22–24% chromium.

Heat resistance

Resists oxidation up to about 1000 °C, for boilers, ovens and furnace parts.

Machining

Ductile and reasonably easy to machine, but it work-hardens quickly: keep tools sharp and use chip breakers.

Welding

Good weldability by conventional methods. Heavy sections may need post-weld treatment to restore corrosion resistance.

Cold working

Raises hardness and strength and improves surface and dimensional accuracy, at some cost to ductility; anneal afterwards if needed.

Annealing

Solution anneal at about 1040–1120 °C, then cool rapidly.

Hardening

Cannot be hardened by heat treatment, only by cold working.
Have a drawing, cut list or sample photo? Upload it and we review it and send you a quote.
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Finishes and processing from Sanmei Metal.

Mill finishes, decorative finishes made in our own facility, and coil and sheet cut to your size.

Decorative finishes

Nickel Silver Hairline Stainless Steel Sheet S26HL-01 (3)
Hairline
Nickel Silver Satin Stianless Steel Sheet S26ST-01 (3)
Satin
black mirror polised stainless steel
Mirror
Nickel Silver Vibration Stainless Steel Sheet S26VB-01 (2)
Vibration
See all decorative finishes →

Mill finishes

Processing

Precision slitting
Cut to length
Shearing
Edge trimming
Blanking
Surface polishing
Tell us about your projectSend a sample photo or drawing

309 or 309S?

The difference is carbon.

309S

Lower carbon reduces the risk of intergranular corrosion in welded structures, with a good balance of strength and corrosion resistance for most high-temperature uses.

309

Slightly higher strength at elevated temperatures.

Applications

Furnaces, boilers, energy (nuclear, fossil fuels, fuel cells), incinerators, heating furnaces, and chemical and petrochemical plants.
Not sure which grade fits?
Tell us about your application
Know more about 309S

The supplier you can trust.

Every order ships with a Mill Test Report.
Click a document to see it full size.
Get a quote with Mill Test Report

309S stainless steel FAQ.

Questions buyers ask before ordering 309S.

How hot can 309S go?

It resists oxidation up to about 980 °C in repeated heating and about 1000–1100 °C in continuous service.

Is 309S magnetic?

No, not in the annealed condition. It is austenitic.

Can 309S be hardened?

Not by heat treatment, only by cold working.

What sizes do you supply?

Coil in 1000, 1219, 1240 and 1500 mm widths or slit to size, 0.15–3.0 mm thick. Sheet in the same widths, 2000 to 3048 mm long, 0.3–3.0 mm thick.
Question not answered here? Ask us directly and our team will reply in person.
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Why project buyers work with Sanmei Metal

Material-driven, engineering-supported, execution-ready. One supplier from the mill to your site.
1

Source from leading partner mills

Base coil from Lisco, Tisco, Jisco, Posco PZSS, Yongjin and Hongwang, each batch with its Mill Test Report.
Our mill partners
2

Finish in-house

PVD, water plating and surface finishing under one roof at our Foshan facility.
Decorative finishes
3

Engineer and fabricate

Our engineers review drawings so profiles and panels can be made and installed.
Architectural metal works
4

Protect and ship

Film matched to laser cutting or stamping, and crates or steel frames packed for sea freight.
Packing and filming
Technical questions about grades, finishes or tolerances?
Technical guide

Our Leading Coating Technology.

Thicker coating, consistent color and easy-clean surfaces. Each one measured in our own production and compared with typical market product.
PVD coating

Thicker PVD coating

0.30µm
Typical coating thickness, up to 28% thicker than a typical market coil, so the color lasts longer.
See the coating test
Color control

Consistent color

ΔE ≤ 2
Every coil is held below the color difference the eye can see, so panels from different batches match.
See the color data
Anti-fingerprint

Fingerprint-resistant

215solvent rubs
Our anti-fingerprint coating withstood 215 rubs with a strong solvent. The standard requires 100. Typical market AF failed at 70.
See the AF test
Tested to GB/T and ISO standards, with MTR and SGS reports on request.
See all our quality control.

Documents you can check.

Every order ships with a Mill Test Report traced to its heat number, and SGS testing is available on request. These are real documents from our mill partners and our project work.
Certifications shown belong to Sanmei and its fabrication partners. Click a document to see it full size.

Tell us about your project.

Send a drawing, a reference photo or just the grade and size. Our team replies with material advice, finish options, samples and a quote.
What helps us answer fastest
Drawing, sketch or reference photo
Grade and thickness, if you know them
Finish or color you have in mind
Quantity and delivery location
Tell us about your project →
Samples and small batches are welcome.

Contact us

Creating Center, Shunde District, Foshan City, Guangdong Province, 528315, China
+8615015653566 / 0757-87668353
Paige Deng
marketing@sanmeimetal.com

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    TEL: +8615015653566 / 0757-87668353
    Email: marketing@sanmeimetal.com

    Headquarters:
    Creating Center, No.142, Yuhe Road, Lecong Town, Shunde District, Foshan City, Guangdong Province, China. 528315

    Factory: Liyuan Logistics City, Chencun Town, Shunde District, Foshan City, Guangdong Province, China. 528313

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