Overview
SS302 (AISI 302 Stainless Steel) is a classic austenitic stainless steel belonging to the 300 Series Stainless Steel Family. It contains higher carbon content than SS304, providing improved strength while maintaining excellent corrosion resistance, formability, and weldability.
SS302 is widely used in springs, wire products, fasteners, stamped components, screens, industrial equipment, and precision mechanical assemblies. Due to its excellent cold-working characteristics, SS302 is one of the most commonly used stainless steels for spring manufacturing and wire forming applications.
Compared with SS301, SS302 offers slightly better corrosion resistance. Compared with SS304, SS302 provides higher strength but slightly lower weldability.
Material Specification
| Property | Value |
|---|---|
| Material Designation | AISI 302 |
| Material Family | Austenitic Stainless Steel |
| UNS Number | S30200 |
| EN Grade | 1.4310 / 1.4319 |
| Density | 7.93 g/cm³ |
| Magnetic Property | Non-Magnetic (Annealed), Slightly Magnetic After Cold Working |
| Standard Forms | Sheet, Plate, Coil, Strip, Wire, Bar, Tube |
Chemical Composition
| Element | Content (%) |
|---|---|
| Iron (Fe) | Balance |
| Chromium (Cr) | 17.0–19.0 |
| Nickel (Ni) | 8.0–10.0 |
| Carbon (C) | ≤0.15 |
| 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 |
Spring Temper Condition
| Property | Value |
|---|---|
| Tensile Strength | 1250–1800 MPa |
| Yield Strength | 900–1600 MPa |
| Hardness | 350–520 HV |
Physical Properties
| Property | Value |
|---|---|
| Density | 7.93 g/cm³ |
| Melting Point | 1400–1455°C |
| Thermal Conductivity | 16.3 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 | Good |
| Humid Environment | Good |
| Marine Environment | Moderate |
| Chloride Environment | Moderate |
| Food Contact Applications | Excellent |
SS302 offers corrosion resistance similar to SS304 in many environments and performs well in food processing, industrial equipment, and architectural applications.
International Equivalent Grades
| Standard | Equivalent Grade |
|---|---|
| ASTM / AISI (USA) | 302 |
| UNS | S30200 |
| EN (Europe) | 1.4310 |
| DIN (Germany) | X10CrNi18-8 |
| JIS (Japan) | SUS302 |
| GB/T (China) | 12Cr18Ni9 |
| ISO | X10CrNi18-8 |
Available Tempers
| Temper | Description |
|---|---|
| Annealed (A) | Soft Condition |
| 1/4 Hard | Light Cold Worked |
| 1/2 Hard | Medium Cold Worked |
| 3/4 Hard | Heavy Cold Worked |
| Full Hard | High Strength |
| Spring Temper | Spring Applications |
| Extra Spring Temper | Maximum Elastic Strength |
Typical Applications
Spring Manufacturing
- Compression Springs
- Extension Springs
- Torsion Springs
- Flat Springs
- Precision Springs
Fastener Industry
- Screws
- Bolts
- Nuts
- Washers
- Retaining Rings
Automotive Industry
- Clamps
- Clips
- Hose Fasteners
- Spring Components
Electronics Industry
- Electrical Contacts
- Battery Springs
- Connector Components
- EMI Shielding Parts
Industrial Manufacturing
- Wire Mesh
- Screens
- Precision Stampings
- Mechanical Components
Food Processing Equipment
- Food Contact Components
- Conveyor Systems
- Processing Equipment
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| Laser Cutting | Excellent |
| Waterjet Cutting | Excellent |
| CNC Machining | Good |
| Stamping | Excellent |
| Deep Drawing | Excellent |
| Cold Forming | Outstanding |
| Wire Forming | Outstanding |
| Welding | Good |
| TIG Welding | Good |
| MIG Welding | Good |
| Polishing | Excellent |
Advantages
Excellent Spring Properties
Widely used for precision spring manufacturing.
Outstanding Work Hardening
Can achieve very high strength through cold working.
Good Corrosion Resistance
Suitable for most industrial and commercial environments.
Excellent Fatigue Resistance
Performs well under repeated cyclic loading.
Excellent Formability
Easy to form, stamp, and bend before hardening.
Good Weldability
Compatible with most common welding processes.
Limitations
Lower Corrosion Resistance Than SS316
Not suitable for aggressive chloride environments.
Becomes Magnetic After Cold Working
Cold forming increases magnetic permeability.
Higher Cost Than 200 Series Stainless
Contains higher nickel content.
Limited Marine Service Life
Continuous seawater exposure requires SS316.
Comparison with Other Stainless Steels
| Property | SS302 | SS301 | SS304 | SS316 | SS430 |
|---|---|---|---|---|---|
| Corrosion Resistance | Excellent | Good | Excellent | Outstanding | Moderate |
| Spring Applications | Excellent | Excellent | Good | Good | Poor |
| Cold Work Strength | Excellent | Outstanding | Good | Good | Moderate |
| Weldability | Good | Good | Excellent | Excellent | Fair |
| Formability | Excellent | Excellent | Excellent | Excellent | Good |
| Cost | Medium | Medium | Medium | High | Low |
Comparison with Common Engineering Metals
| Material | Density (g/cm³) | Corrosion Resistance | Strength | Spring Performance |
|---|---|---|---|---|
| SS302 | 7.93 | Excellent | Very High | Excellent |
| SS301 | 7.93 | Good | Very High | Excellent |
| SS304 | 8.00 | Excellent | Medium | Good |
| Spring Steel 1075 | 7.85 | Poor | Very High | Excellent |
| Aluminum 7075 | 2.81 | Fair | Very High | Good |
| Titanium Grade 5 | 4.43 | Excellent | Very High | Excellent |
Available Surface Finishes
Mill Finishes
- No.1 Finish
- 2B Finish
- BA (Bright Annealed)
- Cold Rolled Finish
Decorative Finishes
- Mirror Polish
- Hairline Finish
- Satin Finish
- Vibration Finish
- Brushed Finish
- Sandblasted Finish
Functional Finishes
- Passivation
- Electropolishing
- Anti-Fingerprint Coating
- Dry Film Lubrication
Frequently Asked Questions (FAQ)
What is SS302 stainless steel?
SS302 is an austenitic stainless steel with excellent corrosion resistance, high strength after cold working, and outstanding spring performance.
What is SS302 used for?
Typical applications include:
- Springs
- Fasteners
- Wire Products
- Precision Stampings
- Electrical Contacts
- Industrial Components
Is SS302 stronger than SS304?
After cold working, yes.
| Property | SS302 Spring Temper | SS304 Annealed |
|---|---|---|
| Tensile Strength | Up to 1800 MPa | ~515–750 MPa |
| Yield Strength | Up to 1600 MPa | ~205–310 MPa |
What is the difference between SS302 and SS304?
| Property | SS302 | SS304 |
|---|---|---|
| Carbon Content | Higher | Lower |
| Spring Performance | Better | Lower |
| Corrosion Resistance | Similar | Similar |
| Weldability | Slightly Lower | Better |
Is SS302 magnetic?
In the annealed condition, SS302 is generally non-magnetic. Cold working may make it partially magnetic.
Can SS302 be welded?
Yes. SS302 can be welded using TIG, MIG, resistance welding, and spot welding processes.
Is SS302 suitable for spring manufacturing?
Yes. SS302 is one of the industry’s most widely used stainless spring materials.
Can SS302 rust?
Under normal atmospheric conditions, SS302 offers excellent corrosion resistance. In marine environments, SS316 is preferred.
Why is SS302 widely used for wire products?
Because it combines:
- High Strength
- Excellent Fatigue Resistance
- Good Corrosion Resistance
- Outstanding Cold Formability
making it ideal for wire forming and spring manufacturing.
Does GCNOV provide custom manufacturing services for SS302?
Yes. GCNOV provides:
- Precision Stamping
- Spring Manufacturing
- Laser Cutting
- CNC Machining
- Sheet Metal Fabrication
- Wire Forming
- Welding & Assembly
- Electropolishing
- Passivation
- Prototype Development
- Mass Production