Stainless Steel Grade 309S: High-Temp Oxidation-Resistant Alloy

Stainless steels are called as high-alloy steels. Due to the presence of large amounts of chromium in the range of 4 to 30%, they have high corrosion resistance than other steels. Stainless steels are classified into martensitic, ferritic and austenitic based on their crystalline structure. However, stainless steels present in the form of a combination of martensitic and austenitic steels are known as precipitation-hardened steels.

 

Chemical Composition

The following table shows the chemical composition of grade 309S stainless steel.

Element	Content (%)
Iron, Fe	60
Chromium, Cr	23
Nickel, Ni	14
Manganese, Mn	2
Silicon, Si	1
Carbon, C	0.080
Phosphorous, P	0.045
Sulfur, S	0.030

Physical Properties

The physical properties of grade 309S stainless steel are given in the following table.

Properties	Metric	Imperial
Density	8 g/cm3	0.289 lb/in³
Melting point	1454°C	2650°F

Mechanical Properties

The mechanical properties of annealed grade 309S stainless steel are displayed in the following table.

Properties	Metric	Imperial
Tensile strength, ultimate	620 MPa	89900 psi
Tensile strength, yield (0.2%)	310 MPa	45000 psi
Izod impact	120 - 165 J	88.5 - 122 ft-lb
Modulus of elasticity	200 GPa	29000 ksi
Shear modulus	77 GPa	11200 ksi
Poissons ratio	0.3	0.3
Elongation at break (in 50 mm)	45%	45%
Hardness, Brinell (converted from Rockwell B hardness)	147	147
Hardness, Knoop (converted from Rockwell B hardness)	164	164
Hardness, Rockwell B	85	85
Hardness, Vickers (converted from Rockwell B hardness)	169	169