1. Structure & Function
Design: Open-ended helical ring made of spring steel, providing elastic tension.
Purpose: Prevents loosening of bolts/nuts under vibration or dynamic loads via continuous spring force.

2. Applications
Anti-vibration: Widely used in automotive, machinery, and construction where vibration occurs.
Pairing: Often combined with flat washers (installation order: bolt → flat washer → spring washer → nut).

3. Standards & Specifications
Standards: DIN 127 (German), GB/T 93 (Chinese), ANSI B18.21.1 (US), sized by bolt diameter (e.g., M8 bolt → 8mm washer).
Materials: Carbon steel (zinc-plated, black-oxidized), stainless steel (A2/A4).

4. Pros & Cons
Pros: Low cost, easy installation, reusability (if elastic limit not exceeded).
Cons:
Fatigue failure under prolonged high-frequency vibration.
Reduced elasticity at high temperatures (>200°C).
Risk of damaging soft materials (e.g., aluminum) during tightening.

5. Alternatives
Threadlocker: Permanent locking but difficult disassembly.
Double Nut: Mechanical interlock for heavy loads; bulkier design.
Self-locking Nuts: Integrated nylon/metal locking (higher cost).

6. Usage Notes
Selection: Match material to environment (e.g., stainless steel for corrosive conditions).
Installation: Orient open end opposite to nut rotation (e.g., left-facing for clockwise tightening).
Avoid: Soft materials, ultra-high-strength bolts (may reduce clamping force).

Summary: Spring washers offer simple, cost-effective vibration resistance for general-purpose fastening but require complementary solutions in extreme conditions.