304 stainless steel is one of the most versatile and widely used austenitic stainless steel grades,known for its excellent corrosion resistance, high temperature resistance,and good machinability, 304 stainless steel is a material of choice in numerous industries. In this blog,let's discuss the definitionof 304 stainless steel, covering its composition,properties,pors and cons.
What is 304 Stainless Steel?
304 stainless steel is a versatile stainless steel material, also known as 18/8 stainless steel,which has a minimum of 18% chromium and 8% nickel, it is resistant to high temperatures of 800℃ and has good processing performance and high toughness.Known for its superior rust resistance compared to the 200 series stainless steels. 304 stainless also exhibits good high-temperature resistance, being able to withstand temperatures up to 1000℃-1200℃. 304 stainless steel possesses excellent corrosion resistance and good resistance to intergranular corrosion.
Stainless Type 304
304L Stainless Steel
304L is the low carbon version of Stainless steel 304.The maximum carbon content is 0.03%.The low carbon chemistry of 304L combined with an addition of nitrogen enables 304L to meet the mechanical properties of 304.
304H Stainless Steel
304H, a high carbon content variant, is also available for use at high temperatures.The carbon content is controlled in the range of 0.04-0.08% for increased strength at temperatures above 800°F (427°C).
SS 304 Chemical Composition
|
% |
304 |
304L |
304H |
|
C |
0.0 - 0.07 |
0.0 - 0.03 |
0.04 - 0.08 |
|
Mn |
0.0 - 2.0 |
0.0 - 2.00 |
0.0 - 2.0 |
|
Si |
0.0 - 1.00 |
0.0 - 1.00 |
0.0 - 1.0 |
|
P |
0.0 - 0.05 |
0.0 - 0.05 |
0.0 - 0.04 |
|
S |
0.0 - 0.03 |
0.0 - 0.02 |
0.0 - 0.02 |
|
Cr |
17.50 - 19.50 |
17.50 - 19.50 |
17.00 - 19.00 |
|
Ni |
8.00 - 10.50 |
8.00 - 10.50 |
8.00 - 11.00 |
|
Fe |
Balance |
Balance |
Balance |
|
N |
0.0-0.11 |
0.0-0.11 |
0.0 - 0.10 |
The high chromium and nickel content are primarily responsible for its excellent corrosion resistance and durability. The carbon content is kept low to prevent carbide precipitation during welding, ensuring better performance in various conditions.
SS304 Material Mechanical Properties
| ASTM | |||
|---|---|---|---|
| Type 304 | Type 304L | Type 304H | |
| 0.2% Offset Yield Strength, ksi | 30 min. | 25 min. | 30 min. |
| Ultimate Tensile Strength, ksi | 75 min. | 70 min. | 70 min. |
| Elongation in 2 inches, % | 40 min. | 40 min. | 40 min. |
| Reduction in Area, % | - | - | - |
| Hardness, Rockwell B | 92 max. | 92 max. | 92 max. |
304 Stainless Steel Physical Property
|
Property |
Value |
|
Density |
8.00 g/cm3 |
|
Melting Point |
1450 °C |
|
Modulus of Elasticity |
193 GPa |
|
Electrical Resistivity |
0.72 x 10-6 Ω.m |
|
Thermal Conductivity |
16.2 W/m.K |
|
Thermal Expansion |
17.2 x 10-6/K |
Corrosion Resistance of Stainless 304
Stainless steel 304 has excellent corrosion resistance in a wide variety of environments and when in contact with different corrosive media. Pitting and crevice corrosion can occur in environments containing chlorides. Stress corrosion cracking can occur at temperatures over 60°C.
304 stainless steel material exhibits superior corrosion resistance compared to the 200 series of stainless steels. It is particularly resistant to oxidation and is effective in environments where it might be exposed to various acids, such as nitric acid. The studies have shown that 304 stainless steel can resist corrosion in nitric acid concentrations up to 65% at boiling temperatures.
In most instances, the corrosion resistance of Grade 304, 304L and 304H will be roughly equal in most corrosive environments. However, in environments that are sufficiently corrosive to cause intergranular corrosion of welds and heat-affected zones 304L should be used due to its low carbon content.
Stainless Steel SS 304 High Temperature Resistance
304 stainless steel can withstand high temperatures, making it suitable for applications involving elevated heat. It remains stable and does not lose its strength up to temperatures of 1000-1200°C(1832-2192°F).
Stainless steel 304 has good resistance to oxidation in intermittent service up to 870°C (1600°F)and in continuous service to 925°C(1690°F). However, continuous use at 425-860°C(800-1580°F ) range is not recommended if corrosion resistance in water is required. In this instance 304L is recommended due to its resistance to carbide precipitation.
Where high strength is required at temperatures above 500°C and up to 800°C, grade 304H is recommended. This type of material will retain aqueous corrosion resistance.
Cold Working of Stainless Steel 304
304 Stainless steel readily work hardens. Fabrication methods involving cold working may require an intermediate annealing stage to alleviate work hardening and avoid tearing or cracking. At the completion of fabrication a full annealing operation should be employed to reduce internal stresses and optimise corrosion resistance.
Hot Working of Stainless Steel 304
Fabrication methods, like forging, that involve hot working should occur after uniform heating to 1149-1260°C. The fabricated components should then be rapidly cooled to ensure maximum corrosion resistance.
304 Stainless Steel Pros
- Excellent corrosion resistance, especially in acidic and salt water environments.
- High temperature stability, suitable for high temperature industrial applications.
- Suitable for high-demand environments in food processing, pharmaceuticals, chemical industries and other fields.
- Good plasticity and processability, easy to form and weld.
304 Stainless Steel Cons
- Relatively high cost due to its high nickel content.
- In some special environments, such as high temperature environments containing chloride salts or sulfides, corrosion may occur.
JBLSTEEL Supplied Forms of Stainless Steel 304
- Pipe
- Tube
- Bar
- Sheet
- Plate
- Strip
- Coil
- Pipe Fittings
- Structural Steel Profiles
- etc
Disclaimer: Many things here represent our opinion. Others are information from the Internet. We can therefore never claim to be correct or complete. And never base a business decision solely on the news you receive from us.
Established in 2008,JBLSTEEL is a professional manufacturer specializing in Stainless Steel.The main grades are 304/L/H,316/L/H,317,310S,309S,410,904L,2205,etc.We have more than 15 years experience in the steel industry with an annual output of nearly 100,000 tons.Being committed to technological innovation and development and making superior quality products, JBLSTEEL always cooperates with famous Steel mills, such as AN STEEL, LY STEEL, BAOSTEEL, TISCO, MA STEEL,etc.
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