Question

The wire ropes which offers better wearing surface and more resistance to bending fatigue is

• A. Lang's Lay
• B. Ordinary lay
• C. Left hand Lay
• D. Right hand Lay

Hint:

Remember the trade-offs:
- Lang's Lay = Better for wear and bending, but prone to untwisting and crushing.
Used where both ends of the rope are fixed, like haulage ropes.
- Ordinary Lay = More stable and crush-resistant, but wears faster.
Used for applications with free ends, like crane ropes and winding ropes.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
We need to identify the type of wire rope construction ("lay") that is superior in terms of wear resistance and resistance to bending fatigue.

Step 2: Detailed Explanation:
The "lay" of a wire rope describes the direction in which the wires are twisted to form a strand, and the direction the strands are twisted to form the rope.
-

Ordinary Lay (or Regular Lay): The wires in the strands are twisted in the opposite direction to the twist of the strands around the rope's core.
This construction results in the outer wires running roughly parallel to the rope's axis.
This makes it more resistant to crushing and distortion and less likely to untwist, but the short exposed length of the outer wires leads to faster wear and lower bending fatigue resistance.
-

Lang's Lay: The wires in the strands are twisted in the

same direction as the twist of the strands around the rope's core.
This construction results in the outer wires running at a diagonal angle to the rope's axis.
This exposes a longer length of each outer wire on the surface of the rope.
The advantages of this are:
1.

Better Wearing Surface: The wear is distributed over a longer length of wire, so the rope wears down more slowly and has a longer service life in high-abrasion applications.
2.

More Resistance to Bending Fatigue: The alignment of the wires and strands allows for better internal movement and stress distribution when the rope bends over sheaves or drums, making it more flexible and resistant to fatigue from repeated bending.

Left hand Lay and

Right hand Lay refer to the direction of the strand twist (Z or S) and can apply to either Ordinary or Lang's lay ropes.
They do not by themselves define the wear and fatigue properties.

Step 3: Final Answer:
Lang's Lay ropes offer a better wearing surface and more resistance to bending fatigue.
This corresponds to option (A).