ZHUHAI JIALI HARDWARE CO., LTD.
How to Select the Right Stainless Steel Grade for Your Fastener Application: A Technical Comparison of SS304, SS316, and Duplex 2205
Choosing the correct stainless steel grade is critical for fastener performance, service life, and total cost of ownership. This guide compares three industry-standard grades used in high-performance applications.
1. AISI 304 (18-8 Stainless)
• Composition: 18% Cr, 8% Ni
• Corrosion Resistance: Excellent in mild atmospheric and freshwater environments; moderate resistance to organic acids.
• Tensile Strength: 515–620 MPa
• Common Applications: General-purpose fasteners in indoor machinery, food processing equipment, architectural fixtures.
2. AISI 316 (Marine-Grade Stainless)
• Composition: 16–18% Cr, 10–14% Ni, 2–3% Mo
• Corrosion Resistance: Superior pitting and crevice corrosion resistance due to molybdenum addition; excellent in saltwater, chemical plants, coastal infrastructure.
• Tensile Strength: 515–620 MPa (similar to 304, but with better ductility)
• Key Limitation: Not resistant to strong reducing acids (e.g., sulfuric acid).
3. Duplex 2205 (UNS S32205/S32202)
• Composition: 22% Cr, 5% Ni, 3% Mo, 0.17% N
• Corrosion Resistance: Outstanding resistance to stress corrosion cracking (SCC), pitting (PREN ≈ 35), and chloride environments.
• Mechanical Properties: Yield strength ~450 MPa (nearly double that of 304/316), exceptional fatigue resistance.
• Applications: Offshore oil & gas platforms, desalination plants, pulp & paper industry, aggressive chemical handling.
Performance Comparison Summary
| Property | SS304 | SS316 | Duplex 2205 |
|---|---|---|---|
| Pitting Resistance (PREN) | 18–20 | 24–26 | 34–35 |
| Yield Strength (MPa) | 205 | 210 | 450 |
| Chloride SCC Resistance | Poor | Fair | Excellent |
| Typical Cost (vs SS304) | 1.0x | 1.5–1.8x | 2.5–3.0x |
Selecting the Right Grade:
• For general indoor use → SS304
• For coastal/marine environments or mild chemicals → SS316
• For offshore, chemical processing, or high-strength requirements → Duplex 2205
At ZHUHAI JIALI HARDWARE CO., LTD., we stock all three grades in standard and custom configurations — from M2 to M24 metric screws, hex bolts, socket cap screws, and specialty washers. All products undergo 100% dimensional inspection, hardness testing, and salt-spray validation per ASTM B117.
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ZHUHAI JIALI HARDWARE CO., LTD. · Precision Stainless Steel Fastener Manufacturer · Est. 2008