304 Stainless Steel and 304L Stainless Steel

Description:

Type 304 Stainless Steel is the most widely used of the austenitic (chromium/nickel) stainless steels. In the annealed condition it is essentially non-magnetic and becomes slightly magnetic with the application of cold work. Type 304L Stainless Steel is preferred in welding applications to exclude the formation of chromium carbides during cooling in the heat affected region of the weld. These alloys represent an excellent combination of corrosion resistance and fabricability.

Product Forms:

Sheet, Strip

Specifications:

Type 304 – ASTM A240, ASTM A666, AMS 5513 Type 304L – ASTM A240, ASTM A666, AMS 5511

Typical Applications:

Chemical equipment and piping, heat exchanger components, dairy and food handling equipment and utensils, cryogenic vessels and components, architectural and structural applications exposed to non-marine atmospheres

Chemical Composition: (Per ASTM A240)

ElementType 304Type 304L
Carbon 0.07Max 0.030 Max
Manganese 2.00Max 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 17.5 to 19.5 18.0 to 20.0
Nickel 8.0 to 10.5 8.0 to 12.0
Nitrogen 0.10 Max 0.10 Max

Mechanical Properties: (Per ASTM A240, A666)

TypeYield Strength 0.2% offset (KSI)Tensile Strength (KSI)% Elongation(2" Gauge length)Hardness Rockwell
304 Ann 30 min. 75 min. 40 min. HRB 92 max.
304 ¼ Hard 75 min. 125 min. 12 min. HRC 25-32 (typical)
304 ½ Hard 110 min. 150 min. 7 min. HRC 32-37(typical)
304L Ann 25 min. 70 min. 40 min. HRB 92 max.
304L ¼ Hard 75 min. 125 min. 12 min. HRC 25-32 (typical)
304L ½ Hard 110 min. 150 min. 6 min. HRC 32-37 (typical)

 

Physical Properties: (annealed)

 

 

304 & 304L

Density (lb./ in^2) @ RT

 

0.29

Modulus of Elasticity in Tension (psi x 10^6)

 

28.0

Specific Heat (BTU/o F/lb.)

32 to 212 oF

0.12

Thermal Conductivity (BTU/hr/ft^2/ft)

212oF

9.4

 

932oF

12.4

Mean Coefficient of Thermal Expansion (in. x 10^-6 per o F)

32 to 212oF

9.2

 

32 to 600oF

9.9

 

32 to 1,000oF

10.2

 

32 to 1,200oF

10.4

Electrical Resistivity (micro ohms - cm)

at 70oF

72

Melting Point Range (oF)

 

2550 to 2650

Oxidation Resistance - Continuous Service(oF)

 

1,650

Oxidation Resistance - Intermittent Service(oF)

 

1,500

Processing:

Types 304 and 304L cannot be hardened by thermal treatment. Annealing: Heat to 1850o F to 2050 o F and cool at sufficiently high rates through 1500oF to 800oF to avoid precipitation of chromium carbides. Stress Relief Annealing: Cold worked parts should be stress relieved at 750oF for ½ to 2 hours.

Forming:

Annealed Types 304 and 304L can be fabricated by roll forming, deep drawing, bending and most other fabrication techniques. Due to the high work hardening rate of these materials, intermediate anneals maybe required to successfully fabricate the part.

Welding:

Types 304 and 304L are weldable by most fusion or resistance welding techniques. If filler metal is required, Type 308 is normally used. Type 304L should be used in heavier sections to reduce the occurrence of carbide precipitation in the heat affected region adjacent to the weld pool

Corrosion:

Types 304 and 304L provides corrosion resistance in a wide range of moderately oxidizing and reducing conditions, fresh water and non-marine applications.