Stainless Steel 309, 310, and 310S are high-temperature chromium–nickel austenitic stainless steels developed for exceptional oxidation resistance and mechanical stability in continuous high-heat environments. These grades exhibit superior resistance to scaling, thermal fatigue, and carburizing atmospheres. SS 309 is suitable for elevated-temperature service, SS 310 offers excellent performance up to extreme temperatures, and SS 310S, with its low carbon content, provides improved weldability and resistance to carbide precipitation.
Commonly used in furnace components, radiant tubes, kiln linings, burners, heat treatment equipment, and thermal processing systems, SS 309/310/310S are trusted for long-term exposure to severe heat and cyclic temperature conditions. Their combination of high-temperature strength, oxidation resistance, and fabrication reliability makes them indispensable for industrial furnace and heating applications.
Other Types of Stainless Steel 309 / 310 / 310S Bars
309/310/310S STAINLESS STEEL ROUND BAR EQUIVALENT GRADES
STANDARD
UNS
WNR.
AFNOR
EN
JIS
BS
GOST
SS 309
S30900
1.4828
–
–
SUS 309
–
–
SS 310
S31000
1.4841 / 1.4307
–
X15CrNi25-20
SUS 310
310S24
20Ch25N20S2
SS 310S
S31008
1.4845
–
–
SUS 310S
–
20Ch23N18
SPECIFICATION OF STAINLESS STEEL 309/310/310S ROUND BAR
Stainless Steel Round Bar Specification
ASTM A276 / A479, ASME SA276 / A479
Dimension Standard
EN, DIN, JIS, ASTM, BS, ASME, AISI
Size
14 mm – 300 mm
Thickness
50 mm to 6000 mm Long
Length
1 to 6 Meters, Custom Cut Length
Form
Round, Square, Hex (A/F), Rectangle, Billet, Ingot, Forging Etc.
CHEMICAL COMPOSITION OF STAINLESS STEEL 309/310/310S ROUND BAR
Grade
C%
Mn%
Si%
P%
S%
Cr%
Ni%
Fe%
309
0.20 max
2.0 max
1.0 max
0.045 max
0.03 max
22.0 – 24.0
12.0 – 15.0
Balance
310
0.25 max
2.0 max
1.50 max
0.045 max
0.03 max
24.0 – 26.0
8.0 – 12.0
Balance
310S
0.08 max
2.0 max
1.50 max
0.045 max
0.03 max
24.0 – 26.0
19.0 – 22.0
Balance
MECHANICAL PROPERTIES OF STAINLESS STEEL 309/310/310S ROUND BAR
Grade
Tensile Strength (ksi)
Yield Strength 0.2% (ksi)
Elongation (%)
Hardness (Brinell) MAX
309
40 min
30 min
40
217
310
75 (515 MPa)
30 (205 MPa)
40
–
310S
75 (515 MPa)
30 (205 MPa)
40
–
PHYSICAL PROPERTIES OF 309/310/310S STAINLESS STEEL ROUND BAR
Grade
Density lb/in³
Thermal Conductivity (BTU/h ft. °F)
Electrical Resistivity (in x 10⁶)
Modulus of Elasticity (psi x 10⁶)
Coefficient of Thermal Expansion (in/in)/°F x 10⁶
Specific Heat (BTU/lb/°F)
Melting Range (°F)
309
0.285 at 68°F
9.0 at 32–212°F
30.7 at 68°F
28.5
8.28 at 32–212°F
0.1200 at 68–212°F
2500 – 2590
GENERAL PHYSICAL DATA OF SS 309/310/310S
Density
Melting Point
8.0 g/cm³
1454°C (2650°F)
💡 Practical Difference in Use
Use Stainless Steel 309 Round Bars when: high oxidation resistance and moderate heat strength are required for components exposed to intermittent or continuous elevated temperatures in furnaces, kilns, and thermal equipment.
→ Example: furnace fixtures, heat shields, burner parts, duct supports, and thermal processing hardware.
Use Stainless Steel 310 Round Bars when: very high temperature resistance, excellent scaling protection, and superior strength are required for continuous service in extreme heat environments.
→ Example: radiant tubes, combustion chambers, furnace rollers, heat exchanger rods, and petrochemical heaters.
Use Stainless Steel 310S Round Bars when: improved weldability, resistance to carbide precipitation, and long-term stability at elevated temperatures are critical for fabricated or welded high-heat assemblies.
→ Example: welded furnace frames, thermal processing supports, incinerator components, high-temperature ducts, and fabricated heater parts.
Stainless Steel 309, 310, and 310S round bars are widely used in high-temperature and oxidation-resistant applications where mechanical stability, corrosion resistance, and thermal endurance are essential.
Heat Treatment & Furnace Equipment: Fixtures, radiant tubes, trays, rollers, and support rods.
