U2 28mm 32mm 48mm Black Galvanizied Steel Studlink Anchor Chain for Marine Buoy

Product Description:

Material Advantages:

Adopt high-quality marine special alloy steel round bar, main grades include CM490 (U2 grade)
The steel forging process optimizes the internal metal structure, eliminating internal stress and significantly improving the chain's tensile, impact and fatigue resistance

Stud Link Type
With internal reinforcing studs, the link structure is stable and not easy to deform, suitable for heavy load anchoring of large ships and offshore engineering
Nominal diameter range: 12.5mm - 120mm; standard link size: inside length 4D, outside width 3.6D (D = nominal diameter)
Standard section length 27.5m, customizable for non-standard lengths according to customer needs
Studless Link Type (Open Link)
No internal studs, lighter weight, easy to match with large shackles, avoiding stud loosening faults
Nominal diameter range: 12.5mm - 70mm; ideal for medium and small vessels, offshore permanent mooring and auxiliary anchoring
Proof load and breaking load meet U2/U3 grade international standards, with accurate load-bearing parameters

Manufacturing Process:

1. Raw Material Preparation and Pretreatment
Select suitable low-carbon steel wire rod (e.g., Q235) with a diameter slightly larger than 8mm to allow for subsequent processing.

Surface treat the steel wire rod to remove oxide scale, oil, and other impurities to avoid affecting subsequent forming and welding quality.

Draw the steel wire rod to a standard diameter of 8mm using a wire drawing machine to ensure the dimensional accuracy of the chain material.

2. Chain Forming and Welding

Chain Braiding: Using specialized chain braiding equipment, bend the 8mm steel wire into "日" (sun) shaped chain links, controlling the inner width and length of the links according to DIN766 standards.

Welding: Use flash butt welding or resistance welding to weld the joints of each chain link to form a closed chain link. After welding, remove weld slag to ensure a smooth joint.

Shaping: Use shaping equipment to correct the shape and size of the chain links, ensuring smooth connection between adjacent links without deformation or jamming.

3. Heat Treatment and Strength Testing

Heat Treatment: The welded chain undergoes overall tempering treatment (e.g., annealing, quenching + tempering) to eliminate welding stress and improve the chain's tensile strength and toughness, meeting the load requirements of marine applications.

Tensile Testing: Randomly selected finished chains are subjected to tensile tests to verify whether their tensile strength and breaking load meet DIN766 standards. Unqualified products are rejected.

Appearance and Dimensional Inspection: The surface flatness and link dimensional deviations of each chain are inspected to ensure there are no defects such as cracks or dents.

4. Hot-Dip Galvanizing for Corrosion Protection

Pre-treatment: The chain surface is cleaned again to remove oil and rust, followed by pickling to remove rust. Finally, it is immersed in a flux to improve the adhesion of the zinc layer.

Hot-Dip Galvanizing: The chain is immersed in molten zinc at 440-460℃ to form a uniform and dense zinc alloy coating on the chain surface. The thickness must meet corrosion protection requirements (typically ≥85μm). Post-treatment: Remove the galvanized chain, cool it, and remove excess zinc nodules from the surface. If necessary, perform passivation treatment to further enhance corrosion resistance.

5. Finished Product Inspection and Packaging: Conduct a final inspection of the galvanized chain, including zinc layer adhesion (e.g., cross-cut test), appearance (no uncoated areas, peeling), and dimensional verification.

Inspected and qualified chains are wound and packaged to the specified length (e.g., 10 meters/coil), labeled with specifications, standards, production date, and other information, and prepared for shipment.

Technical drawings:

Features:

Ultra-high structural strength: The stepped design enhances the chain link's ability to resist stretching and twisting, with U3 grade products capable of withstanding the anchoring tension and wind-wave impact of heavy ships.
Resistant to marine corrosion: Dual protection of hot-dip galvanizing / asphalt coating, allowing long-term immersion in seawater and salt spray environments, significantly reducing corrosion loss.
Impact resistance and fatigue resistance: The chain links can rotate flexibly, effectively absorbing the dynamic impact loads during ship swaying and anchoring, with excellent fatigue resistance.
High adaptability: Perfectly meshing with the ship's anchor winch sprocket, smooth and effortless retraction and extension without slippage, and suitable for various ship anchor accessories and mooring components.
Easy for inspection and maintenance: Surface damage and wear can be directly inspected visually, without the need for professional equipment, facilitating the daily maintenance of the ship's anchoring system. extending the service life of the chain in marine environment

Chain structure: Slotted design. The inner part of the chain links is equipped with solid slot columns to prevent the chain links from stretching, twisting and entangling, thereby enhancing the overall structural strength.
Material and grade: Hot-rolled anchor chain steel (CM490/CM690) is selected. Mainly supplied in U2/U3 grades, and custom stainless steel 316/316L materials are available.
Diameter and length: Standard chain diameter is 36mm. The standard length of each link is 27.5m. The links are joined by connecting chain links / shackles, and custom lengths are supported.
Surface treatment: Options include hot-dip galvanizing (high corrosion resistance) and black asphalt paint coating (anti-sea water erosion), meeting different marine operation environments.
Certification standards: Certified by IACS international classification societies such as CCS, ABS, LR, DNV, BV, NK, IRS, etc., and comply with international and domestic standards ISO 1704, GB/T 549.

Applications:

It is widely used in various commercial ships such as bulk carriers, oil tankers, container ships, and ferries, as well as marine engineering equipment such as offshore wind power platforms, offshore engineering vessels, and port operation vessels. It is used for permanent anchoring and temporary mooring of these ships and equipment. It is suitable for various marine operation environments including the open sea, nearshore areas, and ports, and can cope with complex marine conditions such as wind and waves.

Certification & Load Performance
Obtained authoritative certifications from major international marine classification societies: CCS, ABS, BV, DNV-GL, LR, NK, KR, RINA, IRS
U2 grade proof load 41.2KN-1280KN, breaking load 82.6KN-2560KN; U3 grade proof load 56.4KN-1810KN, breaking load 112.8KN-3620KN (matching with different nominal diameters)
Standard weight 85.41kg-1032kg per 27.5m, with accurate weight parameters for easy shipping and installation calculation

After-sales:

Customization & After-sales
Support non-standard customization of diameter, length, grade and surface treatment
Provide free product samples (freight collect), and sample delivery with 12-hour quick response to inquiries
Flexible delivery cycle, 15-30 days for regular orders, customizable production plan for bulk orders; FOB Qingdao port optional, supporting T/T, L/C at sight and other payment terms

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