Common Types of Nuts and Their Technical Characteristics

There are many kinds of nuts, designed around needs such as anti-loosening, weather resistance, and ease of operation:
Hex Nuts: Divided into three precision grades: A, B, and C. Grade A is used for precision instruments, while grade C is suitable for general equipment. Type II (thickened) can withstand higher loads and is suitable for situations requiring frequent disassembly.
Flange Nuts: Feature an integrated ring-shaped washer at the base, increasing contact area and enhancing sealing. Anti-slip teeth on the surface prevent loosening caused by vibrations, suitable for pipeline connections.
Nylon Nuts: Equipped with an internal nylon ring that provides additional friction through elastic deformation to achieve self-locking. Non-magnetic and resistant to acids and alkalis, suitable for medical and chemical equipment.
Wing Nuts: Side wings allow for manual tightening without tools, commonly used for medical devices or temporary supports that need quick assembly and disassembly.

Differences from Other Fasteners
Bolts: Rods have external threads and require a nut for use; heads are often hexagonal or square, commonly used in heavy-load structures.
Screws: Sharp-ended and can be screwed individually into pre-drilled or threaded holes, such as wood screws or self-tapping screws.
Studs: Threaded on both ends with no head in the middle, fixed with two nuts, used in blind-hole connections.

Selection Principles and Considerations
Parameter Matching: Nominal diameter and thread pitch must match the bolt to avoid thread interference or stripping. For example, an M10 nut should match an M10 bolt, with a pitch generally of 1.5mm (coarse) or 1.25mm (fine).
Materials and Processes: Use stainless steel or alloy steel in high-temperature environments; zinc plating or Dacromet treatment is recommended in humid environments.
Anti-loosening Design: For vibrating conditions, use nylon lock nuts or tab washers; for ultra-high strength requirements, spring washers can be stacked.

In summary, as the "cornerstone" of mechanical connections, the proper selection of nuts directly affects structural stability. In practical applications, load characteristics, environmental conditions, and maintenance requirements must be considered to match the most suitable type and specification.