What is the primary function of spring washers in fasteners?

Spring washers are specifically designed to maintain tension in a fastener assembly and help prevent loosening over time. Their unique shape allows them to absorb any vibration or movement that might otherwise cause a bolt or nut to loosen under operational conditions. When a spring washer is compressed, it exerts a force that keeps components tightly together, making it particularly valuable in applications where vibrations are present.

The other options do not align with the primary purpose of spring washers. While improving surface finish and facilitating easier screwing are benefits associated with some fastener types, they do not define the core function of spring washers. Additionally, while spring washers can help secure components in place, they are not intended for permanently locking two components together, which would typically require other types of fasteners or locking mechanisms.