The strands in a rope are laid around a core of either fibre, steel or solid plastic.
Where the strands are laid over a fibre core FC is used, e.g. 6x19-FC.
Ropes with steel cores should be chosen if the rope is exposed to high working temperature, hard strains, high work rate, hard pressures on drums and blocks etc. The steel core gives better support for the strands, which result in the rope retaining its shape better and giving a better distribution of the stresses in the individual wires.
If the steel core of the rope consists of a single strand the term -WSC is used, e.g. 6x19-WSC.
If the steel core of the rope consists of a steel wire rope the term -IWRC is used, e.g. 6x19-IWRC.
Some steel wire ropes can have a plastic encapsulated core which provides increased stability to the rope and also reduces the wear and corrosion in and around the core, e.g. Dyform 8 PI.