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China Classification Society Fasteners Suppliers - Certified Marine Engineering Fasteners from Our Factory
Products Features
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1. Material Selection
In high-temperature environments (>200â), 42CrMo chromium-molybdenum alloy steel (such as A193 B7) should be used. It can withstand temperatures up to 480â and has a tensile strength of âĨ860 MPa.
Extremely cold environments (<-50â) recommend A320 L7 material with nickel-chromium-molybdenum composite strengthening.
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2. Anti-Loosening Technology
Wedge-shaped lock washers (such as the Nord-Lock system) are used. The geometric structure with a slope angle greater than the thread rise angle is adopted to prevent vibration loosening, and the radial fine teeth form indentations on the contact surface.
⥠Performance Verification: The creep vibration test is used to verify anti-loosening performance â applicable to scenarios with dynamic loads such as wind turbine towers and ship decks.
Application
Classification Society Fasteners (Certified Shipbuilding Fasteners) are specialized fasteners rigorously certified by international ship classification societies (such as DNV, ABS, LR, etc.). Their application fields primarily focus on ships, marine engineering, and related industries.
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(1) Ship Structure Connection
Bolt/nut combinations for critical parts such as decks, bulkheads, and keels. Must comply with ISO 3506-3 standards (salt spray corrosion resistance grade âĨ 720 hours).
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(2) Power System Fixed
Main unit base bolts must pass dynamic load tests (tensile strength âĨ 800 MPa). Material is mostly 316L stainless steel.
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(3) Offshore Platform Construction
Mooring frame connection components must pass the -40â low-temperature impact test and comply with DNV-OS-C501 specification.
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(4) LNG Storage Tank Installation
Low-temperature flange bolts made of nickel-based alloys (such as Inconel 718) ensure sealing performance under -196â conditions.
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(5) Dock Mooring System
Locking nuts must have self-locking function (torque attenuation rate âĪ 5%). Material is duplex stainless steel 2205.
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(6) Offshore Wind Turbine Tower
Foundation ring bolts must meet ISO 4014 tolerance grade (M24âM64) with shear strength âĨ 600 MPa.
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(7) Tidal Energy Device
Underwater fasteners require bio-adhesion protection treatment with coating thickness âĨ 50 Ξm.
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(8) Cross-Sea Bridge Anchor Fixation
Prestressed anchor components must undergo 2 million fatigue tests and comply with EN 1090 standard.
Frequently Asked Questions (FAQ)
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What material should be used for fasteners in high-temperature environments above 200â?
For environments exceeding 200â, 42CrMo chromium-molybdenum alloy steel (e.g., A193 B7) is recommended. This material can withstand temperatures up to 480â and offers a tensile strength of âĨ860 MPa, making it suitable for demanding thermal applications.
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How does the Nord-Lock wedge-shaped lock washer prevent loosening?
The Nord-Lock system uses a geometric structure where the slope angle exceeds the thread rise angle, physically blocking reverse rotation. Additionally, radial fine teeth bite into the contact surface, creating indentations that resist vibration-induced loosening â verified through creep vibration testing.
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Which classification societies certify shipbuilding fasteners?
Classification Society Fasteners are certified by internationally recognized ship classification societies including DNV (Det Norske Veritas), ABS (American Bureau of Shipping), and LR (Lloyd's Register), among others. These certifications ensure compliance with rigorous marine safety and performance standards.
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What fastener material is required for LNG storage tanks operating at -196â?
LNG storage tank flange bolts must be made from nickel-based alloys such as Inconel 718. These materials maintain structural integrity and sealing performance at cryogenic temperatures as low as -196â, preventing leaks and ensuring operational safety.
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What are the requirements for fasteners used in offshore wind turbine tower foundations?
Foundation ring bolts for offshore wind turbine towers must conform to ISO 4014 tolerance grades in the range of M24 to M64, and must achieve a shear strength of âĨ 600 MPa. These specifications ensure the structural reliability of towers under dynamic wind and wave loads.
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What anti-corrosion standards apply to ship structure fasteners?
Fasteners used in critical ship structural connections â including decks, bulkheads, and keels â must comply with ISO 3506-3 standards. This requires a salt spray corrosion resistance grade of âĨ 720 hours, ensuring long-term durability in harsh marine salt environments.