Rotationsfri og rotationssvage stålwire

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Understand the difference between rotation-free and semi-rotation-free steel wire ropes

Stålwirer er essentielle komponenter i mange industrielle applikationer, hvor de bruges til at løfte, trække og bære tunge belastninger, og der findes mange forskellige typer stålwire. To vigtige typer af stålwirer er rotationsfri og rotationssvage stålwirer. Disse wirer har unikke egenskaber, der gør dem velegnede til specifikke anvendelser. De anvendes som regel i enstrengede applikationer som f.eks. tårnkraner eller mobilkraner.

Rotation-resistant steel wire rope

Rotation-resistant steel wire ropes are designed to minimize rotation under load. This is achieved by constructing the wire with multiple layers of strands (also called strands), where the outer strands are twisted opposite to the inner strands. This construction neutralizes the torsional forces when the wire rope is loaded. Even at high loads/lifting heights, the rotation moment (torque) is 0 or around 0.

Rotation-resistant steel wire may be used with a swivel

With rotation-resistant steel wire rope each moment (torque) is:
= 0 or almost 0 to 80% of MBL – rotation-resistant wire rope

Advantages of rotation-resistant steel wire ropes

Increased safety: Less rotation reduces the risk of the load swinging or turning uncontrollably.
Increased safety: Precision: Ideal for applications with critical load positioning.
Increased safety: Long service life: Less mechanical stress on the wire extends its service life.

Applications of rotation-resistant wire ropes include cranes, hoists, and other lifting equipment essential for stability and safety.

Semi-rotation-resistant steel wire ropes

Semi-rotation-resistant wires are designed to reduce, but not eliminate, rotation under load. Their simpler construction compared to rotation-resistant steel wire ropes makes them more economical but still effective in many applications. Semi-rotation-resistant steel wire ropes should not be used with a swivel as the core is inverted, which can result in overloading / only lifting the load via the wire core.

With semi-rotation-resistant wire ropes, each moment (torque) is:
= almost 0 to only 40% of MBL – semi-rotation-resistant wire rope.

Advantages of semi-rotation-resistant steel wire ropes

Cost-effectiveness: Lower production costs make them an economical choice for many companies.
Versatility: This can be used in many applications where complete rotation resistance is not required.
Easier handling: Less complex designs make them easier to install and maintain.

Applications of semi-rotation-resistant steel wire ropes include construction projects, marine applications and general industrial lifting tasks.

Choosing the right steel wire rope

So how do you decide whether you need a rotation-resistant steel wire rope or not? Once you have identified the below mentioned factors, you can enter them in the form below and get the answer.

6 strands + 8 strands wire (moment)

Maximum lifting height depends on:

Diameter blok (sheave) S
Diameter top (sheave) S (or average of both top and block sheaves
Diameter steel wire (d)
Constant C1: Type of reeving: even or odd C1 (even C1 = 2,19 / odd 2,68-2,37)
Constant C2: Wire rope construction (6-strands FC 0,083 / 6-strands IWRC 0,077 / 8-strands IWRC 0,098)

If maximum L is exceeded:
Parts of the rope and block crash into each other, and you need to change parameters.

Or use a rotation-resistant steel wire rope!

Effective rope spacing

Does the block rotate even if you use a rotation-resistant wire rope?

Something is wrong if your block rotates, even if you have chosen a rotation-resistant steel wire rope. If the block rotates without a load, there is a crane problem. This may be due to the wrong groove diameter in the wire rope sheaves or incorrect installation of the wire rope. If the block rotates with a load, it may be due to the wrong choice of rotation-resistant steel wire rope. Choose a wire rope with a different rotation torque.

Also, remember to run a new wire rope in by slowly by running the entire wire rope through the lifting system several times, first with a low load (approximately 20% of WLL) and then with a slightly higher load (approximately 50% of WLL). This will considerably extend the wire rope's service life.

At CERTEX Danmark A/S, we offer a wide range of rotation-resistant and semi-rotation-resistant steel wire ropes that meet the highest standards of quality and reliability.

Our experts are ready to advise you on the best choice for your needs.