Spring characteristics are added by their materials, the heat treatment process, and forming methods (hot/cold forming).

(1)Hot forming and cold forming

=Hot forming

A forming method involving quenching and tempering in order to add necessary strength for the springs after they are formed into shape.

=Cold forming

A forming method involving quenching, tempering, or wire extension for the materials to which necessary strength is already added.

(2)Material for springs

The following table summarizes typical spring materials and application.

[Fig.1] Typical metal materials for springs

Symbol Name Application Major application Method SW-B Hard steel wire ○ - - - - Small coils for general machinery Springs SWP Piano wire ○ - - - ○ Same as above Same as above SWO Carbon steel oil-tempered wire for springs ○ - - - - Medium to large coil springs for general machinery Same as above SWOSC Oil-tempered chromium silicon alloy steel wires for springs - - ○ - ○ Same as above Same as above SUS-WP Stainless steel for springs ○ - - ○ ○ Coil springs requiring corrosion resistance Same as above SUP6 Silicon-manganese steel ○ - - - - Small coil springs for general machinery Hot forming SUP9A Manganese-chromium steel ○ - - - - Medium to large coil springs for general machinery Same as above SK4 Carbon steel ○ - - - - For general and economical disc springs - SUS304 Stainless steel ○ - - ○ ○ Leaf springs and disc springs requiring corrosion resistance -

[Table 2] Characteristics of plastic springs

  Based on the characteristics summarized in [Table 2], plastic springs are adopted for fixing hooks used with tubes and electrical wires.