Characteristic

PROCESSING:

These alloys are not hardenable by heat treatment. Anneal at 1900 – 2050°F (1038 – 1121°C), then water quench or rapidly air cool.

FORMING:

Types 309 and 309S Stainless Steels can be roll formed, stamped and drawn readily. In-process annealing is usually required to reduce hardness and increase ductility.

WELDING:

Type 309 is generally considered to have weldability nearly equivalent to the most common alloys of this class, Types 304 and 304L. When a weld filler is needed, AWS E/ER 309 and 310 are most often specified.

CORROSION:

Types 309 and 309S provide excellent general corrosion resistance. They are more resistant to marine atmospheres than Type 304. They exhibit high resistance to sulfite liquors and are useful for handling nitric acid, nitric-sulfuric acid mixtures, and acetic, citric, and lactic acids.

PHYSICAL PROPERTIES:

Density (lb./ in^2) @ RT		0.29
Modulus of Elasticity in Tension (psi x 10^6)		29.0
Specific Heat (BTU/o F/lb.)	32 to 212 oF	0.12
Thermal Conductivity (BTU/hr/ft^2/ft)	212oF	9.0
	932oF	10.8
Mean Coefficient of Thermal Expansion (in. x 10^-6 per o F)	32 to 212oF	8.3
	32 to 600oF	9.3
	32 to 1,000oF	9.6
	32 to 1,200oF	10.0
Electrical Resistivity (micro ohms – cm)	at 70oF	39.8
Melting Point Range (oF)		2550 – 2650
Oxidation Resistance – Continuous Service(oF)		2000
Oxidation Resistance – Intermittent Service(oF)		1800

MECHANICAL PROPERTIES: (ASTM A167, A240)

Type	Yield Strength 0.2% offset (KSI)	Tensile Strength (KSI)	% Elongation (2″ Gauge length)
309	30 min.	75 min.	40 min.
309S	30 min.	75 min.	40 min.

CHEMICAL COMPOSITION: (A167, A240)

Element	Type 309	Type 309S
Carbon	0.20 max.	0.08 max.
Manganese	2.00 max.	2.00 max.
Sulfur	0.030 max.	0.030 max.
Phosphorus	0.045 max.	0.045 max.
Silicon	0.75 max.	0.75 max.
Chromium	22.0 – 24.0	22.0 – 24.0
Nickel	12.0 – 15.0	12.0 – 15.0