Maximum Operating Temperature
- Zinc on galvanised wires melts at 419°C. At 300°C the zinc begins to soften.
- If a relatively short piece of cable is heated to more than 300°C, the heating affects the inside of the wire rope, the wire rope will become unbalanced and may become locked, causing fractures in the cable/wires to occur more quickly.
- The wires’ mechanical properties, e.g. tensile strength and bending strength, change when the temperature rises. A temperature of e.g. 200°C for 1 hour will reduce the wires’ bending strength.
- An artificial fibre core starts to soften at 80-100°C. A soft core means that the support for the strands disappears and the steel wire rope will become unbalanced, causing fractures in the cable/wires to occur more quickly.
- Sisal cores can tolerate significantly higher temperatures than steel wire rope with artificial fibre cores.
Since tensile strength and pliability/flexibility are often important mechanical properties for a steel wire rope, Randers Reb does not recommend that a steel wire rope with:
- A steel core is subjected to temperatures above 200°C for a longer period of time.
- A sisal core is subjected to temperatures above 200°C for a longer period of time.
- An artificial fibre core is subjected to temperatures above 75°C for a longer period of time.
For a short period of time it can be acceptable for the surface temperature to reach 400°C.
Minimum Operating Temperature
The steel that is used in steel wire rope can be used at extremely low temperatures (minus 200°C or less) without any significant effect on the characteristics of the steel. However, at temperatures of only minus 25°C - 50°C oil and grease will lose their ability to serve as lubricants and protect against rust. This makes the fibre cores easy to damage.
Provided that the steel wire rope does not have a fibre core and that oil and grease are not required as protection against rust or as lubrication, such rope can be used in operating temperatures of approx. minus 200°C. If these conditions cannot be met, the minimum temperature is approx. minus 25°C.