SL: Tension, compression, torsion springs that are cheifly subjected to low static stress.
SM: Tension, compression, torsion springs that are cheifly subjected to medium-high static stress, rarely, dynamic stress.
DM: Tension, compression, torsion springs that are cheifly subjected to medium-high static stress, also for wire shapes that require severe bending.
SH: Tension, compression, torsion springs that are cheifly subjected to high static stress or moderately dynamic stress.
DH: Tension, compression, torsion springs that are mainly submitted to high static strains and to medium levels of dynamic stress.
Music Wire: especially for the manufacture of springs subjest to high stresses or requiring good fatigue properties.