External and internal wear of crane spreader
A very important tool in the hoisting process is the lifting spreader. The lifting spreader takes a long time to use, and the spreader wears out. There are two cases of wear. The outer and inner wear of the spreader is described below：
Internal wear and pressure pit：
This situation is caused by friction between the individual strands in the rope and the steel wire, especially when the wire rope is subjected to bending.
1.The wear of the wire surface of the outer strand of the wire rope is due to the frictional contact of the pulley and the rope groove of the drum under pressure.
2.This phenomenon is particularly noticeable when the wire rope is in contact with the pulley during the acceleration and deceleration movement, and the outer wire is ground into a flat shape.
3.Insufficient lubrication, or incorrect lubrication, and the presence of dust and sand can exacerbate wear.
4.The wear reduces the sectional area of the wire rope and thus the strength. When the outer wire is worn to 40% of its diameter, the wire rope should be scrapped.
5.When the diameter of the wire rope is reduced by 7% or more with respect to the nominal diameter, the wire rope should be scrapped even if no broken wire is found.