Nuts & Washers

Nuts and spring washers are common fastener combinations in mechanical connections. 
Nuts primarily work with bolts to clamp and bear load, ensuring connection strength. 
Spring washers rely on their elasticity to generate preload, preventing loosening due to vibration, and are widely used in applications with high vibration, such as motors, vehicles, and fans.
Nuts are classified by structure into hexagonal nuts, flange nuts, nylon lock nuts, and wing nuts, etc., and by strength into grades 4, 8, and 10, etc. Spring washers mainly include ordinary spring washers, heavy-duty spring washers, and corrugated spring washers.
In terms of materials, both commonly use carbon steel and stainless steel. 
Carbon steel is low-cost and high-strength, suitable for general industrial and construction applications; stainless steel 304 and 316 have strong corrosion resistance and are used in humid, chemical, and coastal environments.
Surface treatments are mostly galvanizing, Dacromet coating, and blackening to improve rust resistance. 
Galvanizing is sufficient for general indoor use, while Dacromet or stainless steel is chosen for outdoor applications and scenarios with high corrosion resistance requirements, comprehensively meeting the needs of different working conditions such as fastening, anti-loosening, and durability.