Fasteners include: bolts, studs, screws, nuts, washers, pins. Locking or seizure often occurs on fasteners made of stainless steel, aluminum alloy and titanium alloy.
The first type is a material that does not require quenching and that requires only stress relief annealing after the spring is formed. These materials are mainly reinforced steel wire, carbon steel wire, piano wire, spring stainless steel wire and various oil quenched and tempered steel wire.