Comparison of Common Stainless Steel Fastener Materials

1. 304 Stainless Steel (A2-70)

The most widely used stainless steel fastener with good rust resistance and high cost performance, suitable for indoor dry environment, general machinery and furniture hardware. Its salt spray resistance reaches 48-100 hours, not fit for coastal and chemical corrosive environment.

2. 316 Stainless Steel (A4-80)

With molybdenum element, it performs much better in chloride corrosion resistance than 304 material, widely used in coastal equipment, seawater facilities and chemical pipelines, with higher price than 304 fasteners.

3. 2205 Duplex Stainless Steel

It features high strength and excellent anti-corrosion performance, stronger than 316 steel, resistant to acid, alkali and seawater erosion, widely used in ships, offshore photovoltaic and marine engineering.

Explanation of Stainless Steel Fastener Strength Grades

A2-70: Standard grade of 304 stainless steel, tensile strength 700MPa; A4-80: High-strength grade of 316 stainless steel, tensile strength 800MPa, better locking performance, not easy to slip or break.

Material Selection Suggestions for Different Working Conditions

• Indoor dry equipment: 304 A2-70 screws and nuts;
• Coastal humid & weak chemical environment: 316 A4-80 fasteners;
• Marine engineering & strong acid-base environment: 2205 duplex stainless steel bolts first choice.