Cast Iron Steel TEE Head Single Marine Mooring Steel Bollard Type T Head Bollard for Port

Material and Manufacturing:

I. Common Materials
Cast Iron
Advantages: Relatively low cost, good casting formability, and easy surface anti-rust treatment and subsequent painting.
Disadvantages: Lower toughness, inferior impact and fatigue resistance compared to cast steel; prone to cracking or brittle fracture under high tension, transverse loads, and repeated loads.
Typical Applications: Traditional, older ports or locations with less extreme load requirements, but modern high-strength moorings generally prefer steel.
Carbon Steel/Mild Steel/Low-Alloy Steel
Advantages: High strength and toughness, capable of withstanding high tension and fatigue loads; moderately priced.
Disadvantages: Requires reliable anti-corrosion treatment, particularly susceptible to corrosion in seawater environments.
Typical Applications: Most modern port bollards, especially T-head bollards and monolithic marine bollards.
Stainless Steel and High-Alloy Steel
Advantages: Excellent corrosion resistance, long service life, and low maintenance costs. Disadvantages: High material cost, heavy weight, and high manufacturing costs.
Typical Applications: Applications requiring extremely corrosive environments or long periods of maintenance-free operation. However, carbon steel/low-alloy steel is still the primary material in large ports.
Cast Steel and Steel Castings
High carbon content combines castability with high strength, making them commonly used for bollards with complex cross-sections.
The production process often requires subsequent heat treatment to enhance strength and toughness.
II. Typical Structures and Types
T-Head Bollard (T-Type Bollard): A common single-piece or modular structure with a T-shaped head, which facilitates force distribution of mooring lines at various angles.
Single-Head/Single-Piece Structure: Simpler to manufacture and install, facilitating on-site maintenance and replacement.
Head Geometry: Typically designed to withstand coupled radial and tensile loads, the head strength, base hole location, and foundation anchor strength must be compatible with offshore operating conditions. III. Production Process (Taking a Carbon Steel/Low-Alloy Steel T-Head Bollard as an Example)
Design and Material Selection
Based on the expected maximum tensile force, lateral load, seawater corrosive environment, and installation foundation conditions, determine the material grade (e.g., low-alloy steel grades such as Q235, Q345, A36, and S355) and heat treatment requirements.
Forging/Casting
Key Selection: Commonly, casting (gray cast iron/ductile iron/cast steel) or forging (for models with higher load-bearing requirements) is used.
Casting: Sand casting, lost wax casting, and other processes are used. Deburring and cleaning of casting defects are required.
Forging (for forgings): Hot rolling/forging is performed to the desired cross-section, followed by rough machining.
Rough Machining and Positioning
Deburring, turning, and milling are performed on the connecting surfaces of the head and base to ensure that the hole position and external tolerances meet the design. Heat Treatment (for carbon steel/low-alloy steel)
Quenching and tempering, normalizing, and quenching and tempering are performed to improve strength and toughness and reduce the risk of brittle fracture.
Hardness and toughness control ensures fatigue life in offshore environments.
Surface Treatment and Corrosion Prevention
The rust prevention process typically includes polishing/sanding, cleaning, phosphating, primer, midcoat, and topcoat.
Common coatings include epoxy resin primer + polyurethane topcoat, or epoxy zinc-rich primer, among other corrosion protection combinations. For marine environments, a thick-coat corrosion protection system is more important.
Galvanizing (hot-dip galvanizing) can also be used as a secondary corrosion protection to extend service life.
Assembly and Inspection
The head and base are secured by bolts, welding, or riveting. Ensure consistent torque and hole positions.
Non-destructive testing (such as ultrasonic, radiographic, and magnetic particle testing) is performed to detect internal defects.
Load Testing: Static and fatigue load tests are typically performed to ensure compliance with standards. Surface Inspection and Certification
Inspect appearance, geometric tolerances, surface defects, coating thickness, corrosion resistance, and other indicators.
Maritime/port-related standards and certifications, such as those from ISO, EN, DNV-GL, and ABS, may be required, depending on the specific region and application.
IV. Selection and Maintenance Recommendations
Environmental factors: Seawater, salt spray, and temperature fluctuations can affect the lifespan of the anti-corrosion system. It is recommended to select an appropriate steel grade and anti-corrosion system.
Load Requirements: If high static tensile forces and repeated fatigue are expected, low-alloy steel with heat treatment and thick coating is preferred.
Maintenance Strategy: Regularly inspect coating integrity and repair worn areas to prevent corrosion extension on the base. For port applications, a galvanized + coating combination or all-stainless steel is preferred to reduce maintenance costs.
Mounting Base: The base must ensure load-bearing capacity and be treated with corrosion protection. Bolted or welded connections must comply with the structural design.

Features:

Performance Specifications
Load Capacity: Static tensile limit, fatigue life, and working load level (WLL) must be specified in accordance with maritime standards or shipyard requirements.
Corrosion Resistance: The coating system and corrosion resistance level for seawater environments, including whether galvanized, epoxy-coated, or stainless steel is used.
Dimensional Tolerances: Tolerances for head height, base thickness, hole location, and straightness must be determined to ensure proper fit with mooring lines.
Quality Inspection: Nondestructive Testing (NDT), coating thickness measurement, and surface defect inspection.

Technical Parameters:

Application Scenarios:

Application Scenarios and Maintenance Key Points
Typical Applications: Mooring points in offshore operations such as port berths, docks, and shipyards.
Maintenance Key Points:
Regularly inspect coating integrity and promptly repair any peeling or cracks.
Inspect bolt holes and joints for corrosion to prevent base loosening.
Regular coating maintenance and possible galvanizing refresh in saltwater environments.
On-site inspections and necessary fatigue assessments before peak load periods.

Support and Services:

After-Sales Service and Maintenance
Maintenance Plans and Recommendations
Schedules and key points for regular inspections, coating maintenance, and fatigue assessments are provided for different environments.
Spare Parts and Replacement Services
Provide quick-replacement parts lists, spare parts inventory recommendations, and emergency supply channels.
Technical Support and Training
Provide operational training, test method training, and technical Q&A channels for on-site personnel and maintenance teams.
Quality and Performance Tracking
Long-term performance data collection, regular follow-up visits, and improvement recommendations ensure compliance with maritime service life expectations.


In addition, we offer a range of services to complement our mooring bollards products. These include custom design and engineering, installation and commissioning, and repairs and upgrades. Our goal is to provide a comprehensive solution to meet your mooring needs, from product selection to ongoing support.
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