The technical characteristics of threaded fasteners include

1) Strength grade: Depending on the material (e.g., carbon steel, alloy steel, stainless steel) and heat treatment process, bolts come in various strength grades such as 4.8, 8.8, 10.9, and 12.9; higher numbers indicate higher tensile strength.

2) Thread specifications: These are primarily categorized into metric (e.g., M6, M8) and imperial (e.g., 1/4-20, 5/16-18) systems, with thread angles typically being 60° (metric and Unified threads) or 55° (Imperial Whitworth threads).

3) Anti-loosening performance: Standard threads are prone to loosening under vibration, leading to the development of various anti-loosening designs, such as nylon-insert locknuts, pre-applied thread-locking adhesives, double-nut arrangements, and spring washers.