ASTM A240 309S & 310S Plate, Sheet, Strip

Corrosion Resistance, Applications, Product Forms

Both 309S and 310S are high chromium and high nickel austenitic stainless steels, primarily developed for use in high temperature and oxidizing corrosion-resistance applications. The UNS designations for 309S and 310S are S30908 and S31008, respectively. The letter “S” stands for special low carbon content of approximate 0.03 to 0.06 in weight percentage. Type 309S resists oxidation up to 1900°F [1038°C] under non-cyclic conditions. Frequent thermal cycling reduces oxidation resistance to about 1850°F [1010°C]. The same holds for Type 310S: it exhibits excellent oxidation resitance up to 2010°F [1100°C] under intermittent-use conditions, while it resists oxidation up to 2100°F [1150°C] under continuous-use conditions.

Type 309S can be used in sulfur containing atmospheres but it is not recommended for use in highly carburizing atmospheres since it exhibits only moderate resistance to carbon absorption. Type 310S is resistant to both sulfidation and moderately carburized atmospheres. In general, both 309S and 310S can be utilized in slightly oxidizing, nitriding, cementing and thermal cycling applications. Especially, 310S also finds usage in cryogenic applications with low magnetic permeability down to -450°F [-268°C]. Both Type 309S and Type 310S can be furnished in flat product forms of plate, sheet, and strip in accordance with ASTM A240. They are widely used for industries such as furnaces, fluidized bed furnaces, paper mill equipment, petroleum refining, power plants, thermal processing, waste treatment, steel plants, sintering/cement plants, ore processing, food processing, and cryogenic components, etc.

Physical Properties

Physical Properties	ASTM A240 Type 309S	ASTM A240 Type 310S
Density	7.89 g/cm3	7.89 g/cm3
Modulus of Elasticity	196 GPa	196 GPa
Specific Heat (0–100°C)	502 J/kg-°K	502 J/kg-°K
Electrical Resistivity @20°C	78.0 Microhm-cm	78.0 Microhm-cm
Melting Range	1480–1530°C	1354–1402°C
Thermal Conductivity	15.6 W/m-°K	10.8 W/m-°K

*Conventional physical properties for ASTM A240 309S and 310S.

Chemical Composition Requirements

Element	Type 309S %	Type 310S %
C	≤0.08	≤0.08
Mn	≤2.00	≤2.00
P	≤0.045	≤0.045
S	≤0.030	≤0.030
Si	≤0.75	≤1.50
Cr	22.0–24.0	24.0–26.0
Ni	12.0–15.0	19.0–22.0

*A revised Schaeffler diagram based on the chemical composition may be used to predict the metallurgical microstructure of ASTM A240 309S and 310S.

Mechanical Properties at Room Temperature

Mechanical Test	309S	310S
Tensile Strength min. MPa [ksi]	515 [75]	515 [75]
Yield Strength min. MPa [ksi]	205 [30]	205 [30]
Elongation in 2", min. %	40	40
Brinell Hardness max. HBW	217	217
Rockwell Hardness max. HRBW	95	95

*Tensile & hardness testing requirements for ASTM A240 309S & 310S.

Creep Properties

Temperature °C	Endurable Strength of 309S, MPa	Endurable Strength of 310S, MPa
538	203	220
593	165	172
649	131	124
704	82	89
760	55	55
816	27	41
871	20	27

*Endurable strength of ASTM A240 Type 309S & 310S at elevated temperatures for 1000 hours, extracted from technical literature of TISCO.

Temperature °C	Creep Strength for 309S, MPa	Creep Strength for 310S, MPa
538	113	227
593	86	158
649	69	103
704	41	69
816	20	20

*Creep strength of ASTM A240 Type 309S & 310S at elevated temperatures for 10000 hours with 1% creep strain, courtesy of TISCO.

Sizes, Dimensions & Manufacturers

We hold large amounts of Type 309S and Type 310S plates, sheets & strips of ASTM A240 in stock. They are procured from prominent manufacturers in China: TISCO, Baowu Steel, JISCO, Tsingshan, and HBIS. Specifications: 1200~3000 mm in width, 0.6~80 mm in thickness, 3000~12000 mm in length.

International Equivalent

Nation/Standard	Designation	Designation
US/ASTM A240	UNS S30908 Type 309S	UNS S31008 Type 310S
China/GB	06Cr23Ni13 (new) 0Cr23Ni13 (old)	06Cr25Ni20 (new) 0Cr25Ni20 (old)
Japan/JIS	SUS309S	SUS310S
EN/DIN	1.4950 X6CrNi23-13	1.4951 X6CrNi25-20

*International equivalent alloy grades for ASTM A240 309S and 310S.