Properties of Stainless Steel 304
Properties of Stainless Steel 304
Stainless steel 304 is one of the most widely used stainless steel types, known for its excellent corrosion resistance, formability, and versatility. Commonly used in various industries, from construction to food processing, stainless steel 304 offers unique properties that make it a top choice for engineers and manufacturers.
Stainless Steel 304, also known as AISI 304, is one of the most widely used stainless steel grades due to its excellent properties. It contains approximately 18% chromium and 8% nickel, which contribute to its corrosion resistance and durability.
Key Properties
- Corrosion Resistance: 304 stainless steel exhibits outstanding resistance to a variety of corrosive environments, although it may suffer from pitting in chloride-rich conditions.
- Strength and Ductility: It has a tensile strength of 520-720 MPa and excellent ductility, allowing for easy fabrication and forming.
- Weldability: 304 is easily welded without requiring post-weld annealing, making it suitable for various applications.
- Temperature Resistance: It can withstand temperatures up to 870°C for intermittent service and 925°C for continuous service.
- Cleanability: Its smooth surface allows for easy cleaning, making it ideal for food processing and medical applications.
Chemical Composition of Stainless Steel 304
The chemical composition of 304 stainless steel includes:
- Carbon (C): ≤ 0.08%
- Manganese (Mn): ≤ 2.00%
- Phosphorus (P): ≤ 0.045%
- Sulfur (S): ≤ 0.030%
- Silicon (Si): ≤ 1.00%
- Chromium (Cr): 18.00–20.00%
- Nickel (Ni): 8.00–10.50%
This combination of chromium and nickel provides superior corrosion resistance, making 304 stainless steel resistant to rust and oxidation.
Mechanical Properties of Stainless Steel 304
The mechanical properties of 304 stainless steel are highly valued in structural and industrial applications.
| Mechanical Property | Value |
| Ultimate Tensile Strength (MPa) | 505 – 735 |
| Yield Strength (MPa) | 215 – 275 |
| Modulus of Elasticity (GPa) | 193 – 200 |
| Elongation at Break (%) | 40 – 60 |
| Brinell Hardness (HB) | 201 |
These properties make 304 grade stainless steel highly durable, with a good balance of strength and ductility.
304 Stainless Steel Cryogenic Properties
One standout property of 304 stainless steel is its ability to maintain strength and toughness at cryogenic temperatures. This makes it suitable for applications in extreme cold environments.
Physical Properties of Stainless Steel 304
304 stainless steel also demonstrates excellent physical properties, contributing to its wide range of applications:
| Physical Property | Value |
| Density (g/cm³) | 7.93 |
| Melting Point (°C) | 1400 – 1450 |
| Thermal Conductivity (W/m·K) | 16.2 |
| Specific Heat (J/kg·K) | 500 |
| Electrical Resistivity (nΩ·m) | 720 |
These physical properties of 304 stainless steel make it suitable for heat exchangers, piping, and other high-temperature applications.
Magnetic Properties of 304 Stainless Steel
Contrary to popular belief, 304 stainless steel is non-magnetic in its annealed state. However, slight magnetism may develop after cold working due to martensitic transformations.
- Magnetic Properties of Stainless Steel 304: Non-magnetic in annealed form, slightly magnetic after cold working.
Corrosion Resistance of 304 Stainless Steel
The corrosion resistance of stainless steel 304 is one of its most notable features. The high chromium and nickel content forms a protective layer that shields the material from oxidation and corrosion.
- 304 Stainless Steel Rusting Properties: Highly resistant to rust, except in chloride-rich environments like seawater.
Comparison: 304 vs 316 Stainless Steel Properties
304 vs 316 stainless steel are often compared due to their widespread use in similar industries. While both types offer excellent corrosion resistance, 316 stainless steel contains molybdenum, which provides enhanced resistance to pitting and crevice corrosion in chloride environments.
| Property | 304 Stainless Steel | 316 Stainless Steel |
| Chromium Content | 18 – 20% | 16 – 18% |
| Nickel Content | 8 – 10.5% | 10 – 14% |
| Molybdenum Content | None | 2 – 3% |
| Corrosion Resistance | High | Superior in chloride environments |
304 is a great all-rounder, while 316 offers additional protection in more aggressive environments, such as marine applications.
304 vs 304L Stainless Steel Properties
304L stainless steel is a low-carbon variant of 304, offering better weldability without sacrificing strength or corrosion resistance.
| Property | 304 Stainless Steel | 304L Stainless Steel |
| Carbon Content | ≤ 0.08% | ≤ 0.03% |
| Weldability | Good | Excellent |
The low carbon content in 304L helps prevent carbide precipitation during welding, making it a better choice for welded structures.
Applications of Stainless Steel 304
The diverse properties of 304 stainless steel make it suitable for a variety of applications, including:
- Construction and Architecture: Used in exterior facades, interior fittings, and structural components.
- Food and Beverage Industry: Due to its non-reactive surface, 304 stainless steel is widely used in food processing equipment, including sinks, containers, and piping.
- Medical Devices: Its non-corrosive and anti-microbial properties make it suitable for surgical tools and implants.
- Chemical Industry: Resistant to acids and chlorides, it is employed in the fabrication of chemical tanks and pipes.
Cold Rolled 304 Stainless Steel Properties
Cold rolling enhances the mechanical properties of 304 stainless steel, improving its strength and hardness:
| Cold Rolled Property | Value |
| Tensile Strength (MPa) | 515 – 1035 |
| Yield Strength (MPa) | 275 – 345 |
This process is essential for applications requiring increased strength, such as automotive and aerospace components.
304 Stainless Steel Material Properties in Food Processing
304 stainless steel is a popular choice in the food industry due to its material properties:
- Corrosion Resistance: Prevents contamination of food.
- Non-reactive Surface: Does not alter the taste or color of food.
- Ease of Cleaning: Its smooth surface helps maintain hygiene standards.
Marine-Grade Properties of 304 Stainless Steel
Although 316 stainless steel is more commonly used in marine environments, 304 stainless steel can also be employed in less corrosive seawater conditions.
304 Stainless Steel Properties in Cryogenic Applications
304 stainless steel maintains its toughness and strength even at very low temperatures, making it an excellent choice for cryogenic applications such as storage tanks and pipelines.
304 Stainless Steel vs Other Grades (430, 409)
Comparing 304 stainless steel with other grades like 430 and 409 highlights the versatility and superior properties of 304.
| Property | 304 Stainless Steel | 430 Stainless Steel | 409 Stainless Steel |
| Corrosion Resistance | High | Moderate | Low |
| Magnetic Properties | Non-magnetic | Magnetic | Magnetic |
304 offers the best combination of strength, corrosion resistance, and non-magnetic properties, making it superior for most applications.
Summary of 304 Stainless Steel Properties Chart
| Property | 304 Stainless Steel |
| Tensile Strength (MPa) | 505 – 735 |
| Yield Strength (MPa) | 215 – 275 |
| Density (g/cm³) | 7.93 |
| Melting Point (°C) | 1400 – 1450 |
| Magnetic Properties | Non-magnetic (annealed) |
| Corrosion Resistance | Excellent |
This chart provides a quick overview of the key mechanical and physical properties of stainless steel 304.
By understanding the properties of 304 stainless steel, industries can make informed decisions about its suitability for various applications, from food processing to structural components, all while benefiting from its durability, corrosion resistance, and versatility.
