Crane Wire Rope Lubrication: Lubricant Requirements, Types, and Methods

Crane wire rope lubrication is essential for reducing wear, preventing corrosion, and extending wire rope service life. Improper lubrication and maintenance can lead to premature damage and replacement. Only 10%–15% of wire ropes scrapped due to damage are attributed to fatigue, while 70%–80% are associated with corrosion and inadequate protection. In harsh operating environments such as metallurgy, mining, and ports, proper lubrication is particularly important for maintaining wire rope performance and service life.

1. Crane Wire Rope Lubrication Conditions and Lubricant Requirements

Wire ropes are pre-lubricated during manufacture, regardless of whether they use a steel core or a fiber core. Therefore, wire rope lubricant mainly provides lubrication and protection during service. It reduces friction between the wires in the strands and between the wire rope and sheave groove, thereby reducing wear. The lubricant film also helps prevent harmful substances such as rainwater, harmful gases, and dust from attacking the wire rope, preventing corrosion, extending equipment service life, and ensuring safe and stable operation.

1.1 High- and Low-Temperature Performance

Wire ropes used on cranes in the metallurgical industry, such as ladle overhead cranes and billet handling cranes, on rolling lines for hot-rolled coil handling, and on hoisting equipment in ironmaking, are exposed to heat radiation for long periods. Loss of lubricant at high temperature not only affects wire rope lubrication, but dripping lubricant can also affect product quality. The lubricant must therefore have good high-temperature resistance. For wire rope lubricants used on lifting equipment operating at low temperatures, inadequate low-temperature performance can cause the lubricant to become brittle and peel off.

1.2 Adhesion

Wire rope lubricant should adhere to the rope surface and form a firm film. The base oil generally has relatively high viscosity. The kinematic viscosity of the base oil for wire rope lubricants used with different equipment is shown in Table 1.

1.3 Penetration

The lubricant should rapidly form a film under load. After the equipment is unloaded, the lubricant on the surface should rapidly penetrate into the rope core and between the strands, providing good lubrication and protection and reducing friction between the wires.

1.4 Extreme-Pressure and Anti-Wear Performance

Under medium and heavy loads, extremely high friction can occur between wires and between the wire rope and equipment during lifting and unloading. The film formed by the wire rope lubricant on the rope surface should have excellent load-carrying capacity, reducing friction and extending wire rope service life.

1.5 Corrosion and Rust Protection

Port equipment is exposed to salt spray for long periods, while tourist cableway and cable-car equipment operates in all-weather conditions. Wire rope lubricant should therefore provide good corrosion and rust protection, keeping the wire rope free from attack by moisture, rainwater, and salt spray.

1.6 Compatibility with Pre-Lubricants

Wire rope lubricant should be compatible with the surface lubricant and fiber-core lubricant applied during pre-lubrication. It should not become diluted and run off after mixing because of structural differences.

To meet special operating conditions, some wire rope lubricants also provide additional properties. For example, petroleum and port machinery users require wire rope surface lubricants to be environmentally degradable and non-polluting to the working environment. Lubricants for mining hoist wire ropes and elevator wire ropes must provide a certain degree of friction increase to increase friction between the wire rope and drive wheel and transmit power effectively.

2. Types of Wire Rope Lubricants

According to their composition, wire rope lubricants can be divided into hydrocarbon-based wire rope surface lubricants, asphalt-based wire rope surface lubricants, soap-based greases, and other types.

2.1 Hydrocarbon-Based Wire Rope Surface Lubricants

Early wire rope surface lubricants and fiber-core lubricants were hydrocarbon-based greases, generally prepared from paraffin wax and mineral wax. They had a relatively low dropping point and an operating temperature range of approximately 45–55°C. Because their melting point was not high, wire rope manufacturers could pre-lubricate ropes conveniently by passing them through an oil bath. However, hydrocarbon-based wire rope surface lubricants are paste-like at room temperature. They melt and flow easily at high temperatures, while at low temperatures they are prone to cracking and peeling.

2.2 Asphalt-Based Wire Rope Surface Lubricants

Like bentonite grease, asphalt-based wire rope surface lubricants have no dropping point. They must be heated or mixed with a diluting solvent during application. After coating, they can cure into a hard black surface that makes inspection inconvenient. They are also prone to cracking and breaking at low temperatures.

2.3 Soap-Based Greases

Common soap-based greases include lithium grease, lithium complex grease, polyurea grease, calcium sulfonate complex grease, and aluminum complex grease. They have semi-fluid flexibility and can partially penetrate the wire rope. They are especially suitable for lubricating wire rope used for low-speed, heavy-load lifting in humid, sea-breeze, and flue-gas environments. Their advantages include a high dropping point and good high-temperature performance.

3. Crane Wire Rope Lubrication Methods

Wire rope lubrication has generally not received sufficient attention from equipment maintenance personnel. Overhead crane wire ropes are mostly lubricated manually, while some equipment uses periodic drip lubrication at the sheave. The source recommends mechanical automatic lubrication, considering it a more reasonable method that can provide effective lubrication and protection, extend equipment service life, and ensure safe and stable operation.

Automatic Lubrication System: Components and Installation

The components shown are: 1. grease drum; 2. air hose assembly with quick connector; 3. pneumatic pump; 4. oil hose assembly with quick connector; and 5. wire rope lubricator.

The wire rope lubrication system consists of a wire rope lubricator, a pneumatic drum pump, an air hose assembly, and an oil hose assembly.

Install the lubricator on the wire rope and use two chain clamps to attach it to a fixed component near the rope being lubricated. It can be positioned vertically, horizontally, or at an angle.

To install the lubricator, first place the four matching sealing rings around the wire rope, with all V-grooves facing the center. Then install the lubricator housing and tighten the bolts.

Install the pneumatic drum pump on the lubricant drum and tighten the screws on the outside of the drum cover against the drum. Connect the pneumatic pump to the grease lubricator with the oil hose.

Connect the pneumatic pump to the air supply and start the wire rope moving. The wire rope surface will then be evenly coated with a layer of lubricant.

Kesimpulan

Effective crane wire rope lubrication requires the lubricant’s properties and application method to match the operating conditions. High- and low-temperature performance, adhesion, penetration, extreme-pressure and anti-wear performance, corrosion protection, and compatibility with pre-lubricants are all discussed in this article. Manual application, drip lubrication, and mechanical automatic lubrication are available methods, with the pneumatic drum pump and wire rope lubricator presented as an example of automatic application.

Cindy

Ada apa: +86 191 3738 6654

Surel: cindywang@hndfcrane.com

Saya Cindy, dengan 10 tahun pengalaman kerja di industri derek dan telah mengumpulkan banyak pengetahuan profesional. Saya telah memilih derek yang memuaskan bagi 500+ pelanggan. Jika Anda memiliki kebutuhan atau pertanyaan tentang derek, jangan ragu untuk menghubungi saya, saya akan menggunakan keahlian dan pengalaman praktis saya untuk membantu Anda memecahkan masalah!