Features and Maintenance of Crane Wire Rope

Features and Maintenance of Crane Wire Rope

Abstract: Wire rope is an essential component of lifting machinery, widely utilized in lifting mechanisms, amplitude mechanisms, traction mechanisms, and even rotating mechanisms. It comes in various structural forms, with wire contact wire rope being a preferred choice. Fiber cores are commonly used, and lubrication is recommended to reduce friction damage. For high-temperature operations, metal cores or soft steel wires are suitable, while galvanized wire ropes are ideal for corrosive environments. The main cause of wire rope breakage is overloading, along with the number of wear wounds on pulleys and rolls. This article explores the features, protection measures, and standards for scrapping wire ropes.

Introduction:

The steel wire rope is a vital component of lifting machinery due to its advantages of deflection, large carrying capacity, and noiseless transmission. The gradual generation of steel wire breaks in the rope stock contributes to its reliability. Consequently, it finds extensive use in rising mechanisms, amplitude mechanisms, traction agencies, and rotating mechanisms.

Types of Rope Stocks:

There are two types of rope stocks for steel wire ropes: round-shaped and heterogeneous stocks. Round-shaped wire ropes are simpler to manufacture and commonly used. Heterogeneous stocks, including triangular stocks, ellipse stocks, and compacted strands, offer denser structures and exhibit higher tensile strength, support surface, and friction resistance. However, their manufacturing complexity limits their widespread use. Wire contact wire ropes are generally preferred due to their advantages of small contact stress, reduced wear, and longer service life.

Choice of Rope Core:

Fiber cores are commonly used in wire ropes and should be lubricated before rope production to minimize friction damage. For high-temperature operations, metal cores or soft steel wires are recommended. In corrosive environments, galvanized wire ropes should be utilized.

Factors Affecting Wire Rope Breakage:

Wire rope breakage is influenced by factors such as overloading, diameter, working environment, working type, and maintenance of wheels and rolls. Each time the wire rope undergoes wear, it experiences a process of bending and straightening, leading to potential damage and breakage. The number of wire wounds and the conditions under which the wire rope operates also contribute to its breaking.

Protection Measures for Wire Rope:

During use, the following measures can help protect the wire rope:

Strictly operate the crane within its rated weight capacity and select a qualified wire rope suitable for the operating category and on-site conditions.

Regularly lubricate the wire rope and frequently inspect its appearance quality. Pay attention to hard-to-reach areas, such as the wire rope at the balance wheel.

Avoid distorting the wire rope during installation. Drag the wires in a clean area, avoid wrapping the rope around other objects to prevent bending or scratches, and use wooden wheels for installation.

Avoid sudden impacts on the wire rope during operation. Gradually tighten the wire rope before hanging equipment to reduce dynamic loads. Sudden unloading while in the air can have adverse effects.

Conduct daily inspections of the wire rope used in on-site construction. Pay special attention to fixed connections and balance wheels, which are critical quality checkpoints.

Standards for Scrapping Wire Rope:

The number of broken wires in a twisted steel wire should not exceed one-tenth of the total wire count. Wire ropes should be scrapped if this limit is exceeded.

Obvious corrosion on the wire rope warrants scrapping. If the radial or corrosion amount exceeds 40% of the original diameter, the wire rope should be scrapped. If it is less than 40%, the number of smaller diameter wires can be reduced as per regulations. A wire rope should be scrapped if its diameter reduces by 7% or more compared to the nominal diameter, regardless of wire breakage.

When hoisting machinery is used to lift hot metal or dangerous goods, the number of scrap wires in the steel wire rope should be half of the standard for general cranes.

Wire ropes with exposed hemp cores or local outer steel wire elongation cage states should be scrapped.

By implementing appropriate protection measures and adhering to scrapping standards, the service life and reliability of crane wire ropes can be maximized.