Marine Double-row Ball Slewing Ring

About product

The Marine Double-row Ball Slewing Ring, incorporating same diameter balls, finds widespread use in wind-driven generators and concrete pump trucks. Specifically, in wind-driven generators, it is commonly installed at the propeller’s base to facilitate variable pitch control, requiring zero clearance, high running accuracy, and a significant starting friction moment. This durable and precise bearing fulfills the demanding requirements of these applications effectively.

  • Ring Material: 42CrMo, 50Mn, or C45 steel
  • Ball/Roller Material: GCr15 steel
  • Cage Material: Either steel 20 or ZL102 cast aluminum alloy
  • Spacer Material: Nylon 6 or nylon 66
  • Quenching Hardness of Raceway:  Ranging from HRC55 to HRC62

Additional information


Port machinery, marine propeller

Outer Diameter


Ball Diameter




Load Ratings ( Coa 10^4N )


Product Detail

The Marine Double-row Ball Slewing Ring bearing offers a compact design that reduces the diameter of mounting holes in both the inner and outer rings, while simultaneously increasing the loading capacity.

Typically composed of three rings, this double-row ball slewing ring bearing allows steel balls and spacers to directly enter the upper and lower raceways. The placement of two sets of steel balls is determined through force analysis. This configuration, with 90° bearing angles in the upper and lower arc raceways, enables the bearing to withstand significant axial force and tilting moments.

In cases where the radial force exceeds one-tenth of the axial force, special design considerations are necessary for the raceway to accommodate the additional radial force effectively.

Material Of Marine Double-row Ball Slewing Ring

The Marine Double-row Ball Slewing Ring is manufactured with specific materials to ensure optimal performance and durability. The range of external diameter for these bearings is typically between 100 mm and 15,000 mm. The materials used for the different components are as follows:

  • Ring Material: The rings are commonly made of 42CrMo, 50Mn, or C45 steel. These materials offer excellent strength, toughness, and resistance to wear and fatigue.
  • Ball/Roller Material: The balls or rollers in the bearing are typically made of GCr15 steel. GCr15 is a high-quality bearing steel known for its hardness, wear resistance, and ability to withstand high loads.
  • Cage Material: The cage, which holds the balls or rollers in position, can be made of either steel 20 or ZL102 cast aluminum alloy. Steel 20 provides robustness and strength, while ZL102 cast aluminum alloy offers lightweight characteristics and corrosion resistance.
  • Spacer Material: Spacers, used to maintain proper spacing between the balls or rollers, are commonly made of nylon 6 or nylon 66. These materials provide good dimensional stability and low friction properties.
  • Quenching Hardness of Raceway: The raceway, subjected to quenching during the manufacturing process, typically has a hardness ranging from HRC55 to HRC62. This hardened raceway ensures enhanced durability and resistance to wear.

Marine Double-row Ball Slewing Ring Applications

The Marine Double-row Ball Slewing Ring finds extensive application in port machinery, where its robust design and capabilities are highly advantageous. Some common applications of this bearing in port machinery include:

  • Cranes: The slewing ring is utilized in various types of cranes used in ports, such as harbor cranes, container cranes, and ship-to-shore cranes. It enables smooth and precise rotation of the crane structure, supporting heavy loads and facilitating efficient cargo handling operations.
  • Excavators: In port settings, excavators are employed for tasks like dredging, digging, and material handling. The double-row ball slewing ring allows the excavator to rotate smoothly, providing stability and load-bearing capacity during operations.
  • Ship Loaders and Unloaders: These machines are responsible for loading and unloading cargo onto and from ships. The slewing ring assists in the rotational movement of the loading/unloading arms, ensuring accurate positioning and efficient transfer of goods.
  • Conveyor Systems: Port conveyor systems transport bulk materials, containers, or packaged goods. The double-row ball slewing ring enables the smooth rotation of the conveyor structure, facilitating the movement of materials along the conveyor lines.
  • Tugboats and Floating Cranes: Tugboats and floating cranes play essential roles in port operations, assisting with berthing, towing, and lifting heavy loads. The slewing ring supports the rotation of the crane or towing arm, allowing for precise maneuvering and reliable lifting capabilities.

Structure Of Marine Double-row Ball Slewing Ring

The structure of the Marine Double-row Ball Slewing Ring:

  • Inner Ring
  • Outer Ring
  • Seal
  • Spacer
  • Ball/Roller

Parameter Of Double-row Ball Slewing Ring

No Gear Type Double-row Ball Slewing Ring

UngearedBoundary Dimensions/mmBolt Hole Diameter/mmStructure Dimensions/mmBasic Load Ratings ( Coa 10^4N )Weight/Kg
020 • 25 • 500 • **616384106580420201852351896264M10*1121100
020 • 25 • 630 • **746514106710550241865364796264M10*1153130
020 • 30 • 800 • **9426581248987023022829823114296M10*1230200
020 • 30 • 1000 • **11428581241098902362210291023114296M10*1286300
020 • 40 • 1250 • **1426107416013741126402612861282150396M10*1482580
020 • 40 • 1600 • **1776142416017241476452616361632150398M10*1620750
020 • 50 • 2000 • **2215178519021491851483320382032178478M10*19871150
020 • 50 • 2800 • **3015258519029492651563328382832178478M10*113901900
020 • 60 • 3550 • **3828327222637383362564535983592214568M10*121103700
020 • 60 • 4500 • **47784222226468843126045454845422145610M10*126704700

External Gear Type Double-row Ball Slewing Ring

External GearedBoundary Dimensions/mmBolt Hole Diameter/mmStructure Dimensions/mmGear Parameters/mmBasic Load Rating (Coa 10^4N)Weight/kg
021 • 25 • 500 • **616384106580420201852351896264M10*15645126600.5121100
022 • 25 • 500 • **616384106580420201852351896264M10*16648105600.5121100
021 • 30 • 800 • **9426581248987023022829823114296M10*18984120800.5230200
022 • 30 • 800 • **9426581248987023022829823114296M10*11099096800.5230200
021 • 40 • 1250 • **1426107416013741126402612861282150396M10*1121500122900.5482580
022 • 40 • 1250 • **1426107416013741126402612861282150396M10*1141498104900.5482580
021 • 60 • 3150 • **3428287222633382962564531983192214568M10*12035401741500.518703330
022 • 60 • 3150 • **3428287222633382962564531983192214568M10*12235421581500.518703330
021 • 60 • 4500 • **47784222226468843126045454845422145610M10*12248842191500.526704700
022 • 60 • 4500 • **47784222226468843126045454845422145610M10*12549001931500.526704700

Internal Gear Type Double-row Ball Slewing Ring

Internal GearedBoundary Dimensions/mmBolt Hole Diameter/mmStructure Dimensions/mmGear Parameters/mmBasic Load Rating (Coa 10^4N )Weight/kg
023 • 25 • 500 • **616384106580420201852351896264M10*1535572600.5121100
024 • 25 • 500 • **616384106580420201852351896264M10*1634859600.5121100
023 • 30 • 800 • **9426581248987023022829823114296M10*1861678800.5230200
024 • 30 • 800 • **1006581248987023022829823114296M10*11061062800.5230200
023 • 40 • 1250 • **1426107416013741126402612861282150396M10*112100885900.5482580
024 • 30 • 800 • **1426107416013741126402612861282150396M10*114100873900.5482580
23 • 50 • 2000 • **2215178519021491851483320382032178478M10*11616961071200.59871150
024 • 50 • 2000 • **2215178519021491851483320382032178478M10*1181696951200.59871150
023 • 60 • 3150 • **3428287222633382962564531983192214568M10*12027601391500.518703300
024 • 60 • 3150 • **3428287222633382962564531983192214568M10*12227501261500.518703300
023 • 60 • 4500 • **47784222226468843126045454845422145610M10*12241141881500.526704700
024 • 60 • 4500 • **47784222226468843126045454845422145610M10*12541001651500.526704700



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About our company

Zava Marine Corporation is a leading supplier of marine parts and components. With a strong focus on quality and customer satisfaction, we specialize in providing a comprehensive range of high-quality marine equipment and accessories. Our products include deck equipment, ship accessories, and various other essential components needed for smooth maritime operations.

With a global presence, we serve a diverse customer base, including shipbuilders, shipowners, offshore operators, and marine equipment distributors. We are committed to providing exceptional service and tailored solutions to meet our customers’ unique needs.


Zava Marine offers a comprehensive range of certifications for marine parts in accordance with international standards and regulations. These certifications include those provided by renowned marine classification societies such as Lloyd’s Register (LR), Bureau Veritas (BV), China Classification Society (CCS), Registro Italiano Navale (RINA), American Bureau of Shipping (ABS), Nippon Kaiji Kyokai (NK), and Det Norske Veritas – Germanischer Lloyd (DNV-GL). By collaborating with these esteemed societies, Zava Marine ensures that our certified marine parts meet the highest standards of safety, quality, and performance, instilling confidence in our reliability and compliance within the maritime industry.

The warranty provided by Zava Marine covers defects in materials and workmanship for a period of two years from the date of purchase. During this warranty period, if any marine parts purchased from Zava Marine exhibit issues or failures resulting from manufacturing defects or faulty materials, Zava Marine will take responsibility for repair or replacement of the affected parts. 

Zava Marine has recently opened new molds for European and North American clients, utilizing materials such as metal, ABS, PVC, and more. These successful mold opening projects allow us to provide customized marine parts and components that meet the specific requirements of our clients in these regions.

Typically, Zava Marine can ship samples within 7 days once the product drawing has been mutually confirmed by both parties. This efficient process ensures that customers can receive samples promptly, allowing them to assess the quality and suitability of the products.

Zava Marine frequently utilizes a wide range of materials in our projects. These materials include aluminum, stainless steel, carbon steel, copper, plastics, titanium, and PEEK (Polyether Ether Ketone). Each material offers unique properties and characteristics suitable for various marine applications. 

Yes, we provide customization services for marine parts. We understand that every project and application may have unique requirements, and we are committed to delivering tailored solutions. By collaborating closely with our clients, we can adapt our products to specific specifications, ensuring optimal fit, performance, and compatibility. Whether it’s modifying existing designs or creating entirely new parts, our customization services cater to the diverse needs of the maritime industry.

Absolutely! We offer product design and development services to support our clients’ needs. Our experienced team of engineers and designers can collaborate with clients from concept development to final product realization. By leveraging our expertise in marine engineering and design, we can provide valuable insights and innovative solutions. Whether it’s optimizing existing designs or creating entirely new products, we are equipped to assist clients in bringing their ideas to life efficiently and effectively.

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