The Influence on Materials of Slewing Bearing

In the industrial field, slewing bearings serve as the crucial hubs of various large – scale mechanical equipment. They can be found everywhere, from the tower cranes on construction sites to the rotating bases of astronomical telescopes. A slewing bearing not only has to withstand huge axial forces, radial forces, and overturning moments but also ensures that the equipment can rotate flexibly and smoothly. The realization of all these performances depends on high – quality materials.

What is a Slewing Bearing?

A slewing bearing is a large – scale bearing capable of withstanding comprehensive loads. It plays a vital connecting and supporting role in numerous large – scale mechanical equipment. Its structure mainly consists of an inner ring, an outer ring, rolling elements, and a cage. The relative rotation is achieved through the rolling of the rolling elements between the inner and outer rings, thereby supporting the smooth rotation of equipment components. Slewing bearings can withstand large axial forces, radial forces, and overturning moments and are widely used in equipment such as cranes, excavators, wind turbines, and solar tracking systems. It not only ensures the structural stability of the equipment but also enables the equipment to operate flexibly under complex working conditions, playing a key role in enhancing the overall performance and work efficiency of the equipment.

Characteristics and Applications of Commonly Used Materials

Medium – Carbon Alloy Steel: The Balance of Strength and Toughness

Medium – carbon alloy steel is one of the commonly used materials for slewing bearings, with 42CrMo steel being a typical representative. The carbon content of such steel is between 0.3% – 0.6%. After appropriate quenching and tempering treatments, it can possess excellent strength and toughness. In large – scale port cranes, the slewing bearing needs to bear a lifting weight of dozens to hundreds of tons and also withstand the impacts caused by frequent starting, stopping, and turning. With a yield strength of over 930MPa and a tensile strength of over 1080MPa, 42CrMo steel firmly supports the upper structure of the crane, ensuring the normal rotation of the turntable under heavy workloads, avoiding deformation or fracture due to excessive stress, and ensuring the efficient and safe operation of cargo handling operations.

Alloy Structural Steel: The Combination of Wear Resistance and Toughness

20CrMnTi, a low – carbon alloy carburizing steel, is also an ideal material for slewing bearings. Its carbon content is approximately 0.2%. After carburizing, quenching, and low – temperature tempering treatments, the surface hardness can reach HRC58 – 62, forming a hard and wear – resistant surface layer, while the core still maintains good toughness. In the construction machinery field, such as the slewing platform support of excavators, during operation, it not only has to withstand the strong impact force generated by excavation operations but also resist the wear caused by long – term rotation. The high – hardness surface layer of 20CrMnTi steel after carburization effectively reduces the degree of wear and extends the service life, and the toughness of the core ensures that it will not undergo brittle fracture when subjected to instantaneous impacts, guaranteeing the stable operation of the excavator.

Special – Performance Materials: Coping with Extreme Working Conditions

In some special environments, ordinary alloy steels are difficult to meet the requirements, so special – performance materials have emerged. In the slewing bearings of high – temperature furnaces in the metallurgical industry, high – temperature alloys come into play. For example, the Inconel 718 alloy can still maintain a relatively high yield strength and tensile strength at a high temperature of 650°C. With its good high – temperature strength, oxidation resistance, and thermal stability, it can work stably in a high – temperature environment for a long time, ensuring the normal operation of the furnace. In the marine engineering field, since the equipment is long – term exposed to high – humidity and highly corrosive seawater, 316L stainless steel has become one of the preferred materials for slewing bearings. It is rich in nickel and molybdenum elements and has excellent seawater corrosion resistance, which can effectively resist seawater erosion, prevent rust and corrosion, extend the service life of the equipment, and reduce maintenance costs.

Consideration Factors in Material Selection

The selection of slewing bearing materials is a comprehensive trade – off process. First, the working conditions of the equipment are key factors. The magnitude of the working load, the speed of rotation, and the temperature, humidity, and pH value of the operating environment all determine the required properties of the materials. For example, in the slewing bearings of high – speed centrifuges, the materials not only need to have high strength and hardness but also good dynamic balance performance to avoid vibrations and noises generated by high – speed rotation. Second, the machinability of the materials cannot be ignored, including cutting machinability, forging performance, and heat treatment performance. Materials that are easy to process can reduce manufacturing costs and improve production efficiency. Finally, cost factors also play an important role in material selection. Under the premise of meeting performance requirements, choosing materials with high cost – performance can effectively control the overall cost of the equipment and improve the competitiveness of products.

New Trends in Material Development

With the continuous progress of industrial technology, slewing bearings face more complex working conditions and higher performance requirements, and material development also shows new trends. On the one hand, high – performance materials are constantly emerging. For example, ceramic – matrix composites combine the high hardness and high – temperature resistance of ceramics with the high strength and high toughness of composites, and are expected to be widely used in slewing bearings in fields such as aerospace and high – speed precision machinery. On the other hand, the greening and sustainable development of materials have also become an important direction. The development of environmentally friendly and recyclable materials can not only reduce the impact on the environment but also achieve the recycling of resources. At the same time, the development of material surface treatment technology has opened up new ways to improve the performance of slewing bearings. Through advanced technologies such as nano – coatings and ion implantation, a special – performance layer can be formed on the surface of the materials, further improving their wear resistance, corrosion resistance, and fatigue life.

The Price of Slewing Bearing Materials

The prices of slewing bearing materials are affected by multiple factors. First, the cost of raw materials is a major factor. The price fluctuations of alloying elements such as chromium and molybdenum directly affect the cost of steel. If the steel contains scarce elements such as tungsten and vanadium, the price will increase due to the high difficulty of mining and acquisition. Second, the production process difficulty is also crucial. Advanced smelting and high – precision processing not only require specialized equipment but also rely on high – tech personnel, greatly increasing the cost. Finally, market supply and demand have a significant impact. With the development of the wind power and construction machinery industries, the demand for slewing bearings has increased. When the demand exceeds the supply, the material price rises. Conversely, if the production capacity of material manufacturers is sufficient and the output is high, resulting in oversupply, the price will decline.

Supplier of Slewing Bearings

LDB Bearing always adheres to the concept of “win – win with customers” and embodies the responsibility of modern industry. With innovation and quality at its core, LDB Bearing continuously provides global customers with products and services beyond expectations. LDB Bearing is not only a link in mechanical transmission but also a powerful engine driving the industrial civilization to a higher level.