Overview
SS304 (AISI 304 Stainless Steel) is the world’s most widely used stainless steel and belongs to the 300 Series Austenitic Stainless Steel Family. Known as the industry standard stainless steel, SS304 offers an excellent combination of corrosion resistance, strength, weldability, formability, hygiene, and cost-effectiveness.
Containing approximately 18% chromium and 8% nickel, SS304 is commonly referred to as 18/8 Stainless Steel. It is extensively used in food processing equipment, medical devices, architectural structures, kitchen equipment, automotive components, industrial machinery, and consumer products.
Compared with SS201 and SS202, SS304 provides significantly better corrosion resistance. Compared with SS316, SS304 offers lower cost but reduced resistance to chlorides and marine environments.
Material Specification
| Property | Value |
|---|---|
| Material Designation | AISI 304 |
| Material Family | Austenitic Stainless Steel |
| UNS Number | S30400 |
| EN Grade | 1.4301 |
| Density | 8.00 g/cm³ |
| Magnetic Property | Non-Magnetic (Annealed), Slightly Magnetic After Cold Working |
| Standard Forms | Sheet, Plate, Coil, Pipe, Tube, Bar, Wire |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| Chromium (Cr) | 18.0–20.0 |
| Nickel (Ni) | 8.0–10.5 |
| Carbon (C) | ≤0.08 |
| Manganese (Mn) | ≤2.00 |
| Silicon (Si) | ≤1.00 |
| Phosphorus (P) | ≤0.045 |
| Sulfur (S) | ≤0.030 |
| Nitrogen (N) | ≤0.10 |
Mechanical Properties
Annealed Condition
| Property | Value |
|---|---|
| Tensile Strength | ≥515 MPa |
| Yield Strength | ≥205 MPa |
| Elongation | ≥40% |
| Hardness | ≤92 HRB |
| Elastic Modulus | 193 GPa |
| Fatigue Strength | 240 MPa |
Cold Worked Condition
| Property | Value |
|---|---|
| Tensile Strength | Up to 1200 MPa |
| Yield Strength | Up to 1000 MPa |
| Hardness | Up to 350 HV |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.00 g/cm³ |
| Melting Point | 1400–1450°C |
| Thermal Conductivity | 16.2 W/m·K |
| Electrical Resistivity | 0.72 μΩ·m |
| Thermal Expansion Coefficient | 17.2 × 10⁻⁶/K |
| Specific Heat Capacity | 500 J/kg·K |
Corrosion Resistance
| Environment | Performance |
|---|---|
| Indoor Environment | Excellent |
| Atmospheric Exposure | Excellent |
| Industrial Environment | Excellent |
| Humid Environment | Excellent |
| Food Processing Environment | Excellent |
| Marine Environment | Good |
| Chloride Environment | Moderate |
SS304 offers excellent resistance to oxidation, moisture, food acids, and most industrial atmospheres. However, prolonged exposure to chlorides and seawater may lead to pitting corrosion.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM / AISI (USA) | 304 |
| UNS | S30400 |
| EN (Europe) | 1.4301 |
| DIN (Germany) | X5CrNi18-10 |
| JIS (Japan) | SUS304 |
| GB/T (China) | 06Cr19Ni10 |
| ISO | X5CrNi18-10 |
Available Forms
| Product Type | Availability |
|---|---|
| Stainless Steel Sheet | Yes |
| Stainless Steel Plate | Yes |
| Stainless Steel Coil | Yes |
| Stainless Steel Pipe | Yes |
| Stainless Steel Tube | Yes |
| Stainless Steel Bar | Yes |
| Stainless Steel Wire | Yes |
| Forgings | Yes |
Typical Applications
Food & Beverage Industry
- Food Processing Equipment
- Commercial Kitchen Equipment
- Food Storage Tanks
- Dairy Equipment
- Brewery Equipment
Medical Industry
- Surgical Instruments
- Medical Devices
- Laboratory Equipment
- Pharmaceutical Equipment
Architectural Industry
- Building Facades
- Handrails
- Decorative Panels
- Elevator Interiors
- Curtain Wall Components
Automotive Industry
- Exhaust Systems
- Decorative Trim
- Fuel Components
- Structural Brackets
Industrial Manufacturing
- Storage Tanks
- Pressure Vessels
- Pumps
- Valves
- Heat Exchangers
Consumer Products
- Kitchen Sinks
- Cookware
- Water Bottles
- Household Appliances
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| Laser Cutting | Excellent |
| Waterjet Cutting | Excellent |
| CNC Machining | Good |
| Stamping | Excellent |
| Deep Drawing | Excellent |
| Bending | Excellent |
| Welding | Excellent |
| TIG Welding | Excellent |
| MIG Welding | Excellent |
| Polishing | Excellent |
Advantages
Excellent Corrosion Resistance
Suitable for most industrial, food-grade, and architectural applications.
Outstanding Weldability
Compatible with virtually all common welding processes.
Excellent Formability
Can be deep drawn, stamped, bent, and fabricated easily.
Hygienic Surface
Easy to clean and maintain, making it ideal for food and medical applications.
Attractive Appearance
Supports mirror polishing, brushing, and decorative finishes.
Global Availability
One of the most widely available engineering materials worldwide.
Limitations
Lower Chloride Resistance Than SS316
Not ideal for marine or coastal applications.
Higher Cost Than SS201 and SS202
Due to higher nickel content.
Work Hardening During Machining
Can increase tool wear during CNC machining.
Moderate Thermal Conductivity
Lower heat transfer than aluminum and copper.
Comparison with Other Stainless Steels
| Property | SS304 | SS201 | SS202 | SS316 | SS303 |
|---|---|---|---|---|---|
| Corrosion Resistance | Excellent | Good | Good | Outstanding | Good |
| Weldability | Excellent | Good | Good | Excellent | Poor |
| Machinability | Good | Good | Good | Good | Excellent |
| Food Grade | Excellent | Good | Good | Excellent | Good |
| Marine Resistance | Good | Poor | Poor | Excellent | Fair |
| Cost | Medium | Low | Low | High | Medium |
Comparison with Common Engineering Metals
| Material | Density (g/cm³) | Corrosion Resistance | Strength | Food Grade |
|---|---|---|---|---|
| SS304 | 8.00 | Excellent | Medium | Excellent |
| SS316 | 8.00 | Outstanding | Medium | Excellent |
| Aluminum 6061 | 2.70 | Good | Medium | Good |
| Carbon Steel 1018 | 7.85 | Poor | Medium | No |
| Brass C360 | 8.47 | Good | Medium | Good |
| Titanium Grade 2 | 4.51 | Excellent | Medium | Excellent |
Available Surface Finishes
Mill Finishes
- No.1 Finish
- 2B Finish
- BA (Bright Annealed)
- No.4 Finish
Decorative Finishes
- Mirror Polish (8K)
- Hairline Finish
- Satin Finish
- Vibration Finish
- Brushed Finish
- Sandblasted Finish
- Etched Finish
Functional Finishes
- Passivation
- Electropolishing
- Anti-Fingerprint Coating
- PVD Coating
Frequently Asked Questions (FAQ)
What is SS304 stainless steel?
SS304 is the most commonly used stainless steel grade, offering excellent corrosion resistance, weldability, hygiene, and formability.
What is SS304 used for?
Typical applications include:
- Food Equipment
- Medical Devices
- Kitchen Equipment
- Architectural Structures
- Industrial Machinery
- Storage Tanks
Is SS304 food grade?
Yes. SS304 is one of the most widely accepted food-grade stainless steels globally.
What is the difference between SS304 and SS316?
| Property | SS304 | SS316 |
|---|---|---|
| Corrosion Resistance | Excellent | Outstanding |
| Chloride Resistance | Moderate | Excellent |
| Marine Applications | Limited | Recommended |
| Cost | Lower | Higher |
Is SS304 magnetic?
In the annealed condition, SS304 is generally non-magnetic. Cold working may introduce slight magnetism.
Can SS304 rust?
Under normal conditions, SS304 resists rust extremely well. However, chloride-rich environments may cause pitting corrosion.
Is SS304 suitable for outdoor applications?
Yes. SS304 performs very well in most outdoor environments, especially inland areas.
Can SS304 be welded?
Yes. SS304 offers excellent weldability with TIG, MIG, resistance welding, and laser welding.
Why is SS304 the most popular stainless steel?
Because it combines:
- Excellent Corrosion Resistance
- Good Strength
- Outstanding Fabrication Performance
- Food Safety Compliance
- Competitive Cost
making it suitable for thousands of applications worldwide.
Does GCNOV provide custom manufacturing services for SS304?
Yes. GCNOV provides:
- CNC Machining
- Laser Cutting
- Sheet Metal Fabrication
- Tube Fabrication
- Welding & Assembly
- Mirror Polishing
- Electropolishing
- Passivation
- Prototype Development
- Low-Volume Production
- Mass Production