An operator observes that the bottom of the sheave groove for a 25 mm wire rope has become significantly flattened and worn. The side walls are also showing signs of wear. What is the term for this type of sheave wear, and what is its effect on the rope?

Question: An operator observes that the bottom of the sheave groove for a 25 mm wire rope has become significantly flattened and worn. The side walls are also showing signs of wear. What is the term for this type of sheave wear, and what is its effect on the rope?

Answer options:

• Undercutting; it loosens the rope and causes excessive play.
• Corrugation; it grips the rope too tightly and reduces flexibility.
• Peening; it polishes the rope surface and reduces friction. ✅ Grooving or 'U'-shaped wear; it causes the rope to be pinched and abraded.

Correct answer: Grooving or 'U'-shaped wear; it causes the rope to be pinched and abraded.

Explanation: When sheaves become severely worn, especially in the bottom of the groove with flattening and worn sidewalls, it's often referred to as grooving or 'U'-shaped wear. This condition alters the sheave's proper support for the rope, typically causing the rope to be pinched and abraded, which accelerates wire fatigue, distorts the rope's cross-section, and significantly reduces its lifespan. CSA Z150 mandates sheave replacement or re-machining when such wear is evident.