Ship Fasteners — Complete Marine Grade Bolts, Nuts, Washers and Studs for Vessel Construction

Ship fasteners are the complete range of bolts, nuts, washers, studs, and threaded rods specified across every system on a marine vessel — from hull structural connections and engine room machinery to deck equipment mounting and piping flange joints. Unlike general-purpose industrial fasteners, marine fasteners must meet additional requirements for saltwater corrosion resistance, vibration loosening resistance, and material traceability under classification society rules. SINOFASTENER manufactures and supplies a full range of ship bolts and nuts per ISO, DIN, ASTM, and EN standards, covering M6–M64 in carbon steel Grade 8.8/10.9 and A4-70/A4-80 (316) stainless steel.

With an annual production capacity of 50,000 tons and in-house heat treatment, galvanizing, and salt spray testing, SINOFASTENER supplies marine grade fasteners to shipyards, ship repair yards, and marine equipment manufacturers worldwide. Every shipment includes EN 10204 3.1 material certificates, with third-party inspection available by ABS, DNV, LR, BV, or CCS surveyors upon request.

What Are Ship Fasteners?

Ship fasteners is the collective term for all mechanical fasteners used in the construction, outfitting, and maintenance of marine vessels. The marine environment imposes three demands that distinguish ship fasteners from land-based structural or machinery fasteners:

• Corrosion resistance — continuous exposure to salt spray, seawater splash, and high humidity requires hot-dip galvanizing (ISO 1461) or stainless steel A4 (316) material selection
• Vibration resistance — main engine vibration, propeller excitation, and wave impact require anti-loosening measures such as spring washers (DIN 127), prevailing torque nuts, or thread locking compounds
• Traceability — classification society rules require material certificates and heat number traceability for all primary structural and pressure-boundary fasteners

The complete shipbuilding fasteners product range includes:

• Hexagon bolts — ISO 4014 (partial thread) / ISO 4017 (full thread), Grade 8.8/10.9
• Stud bolts and threaded rods — ASTM A193 B7/B8/B8M, DIN 975/976, for flange and machinery connections
• Hex nuts and heavy hex nuts — ISO 4032, ASTM A194 2H/8/8M, property-class matched to bolts
• Washers — flat washers DIN 125/ISO 7089, spring washers DIN 127, hardened washers for structural joints
• U-bolts — DIN 3570, for pipe clamping and deck anchoring
• Eye bolts — DIN 580, forged lifting points with WLL marking
• Socket head cap screws — DIN 912/ISO 4762, for machinery and equipment mounting
• Foundation anchor bolts — L/J/U-type, for equipment baseplate and crane foundation anchoring

Marine Applications by Ship Zone

Note: Application examples below are based on typical industry practice for marine vessel fastener selection and relevant ISO/ASTM/EN standard scope definitions.

Specifications and Materials

Bolts — ISO 4014 / ISO 4017 / ASTM A193

Nuts — ISO 4032 / ASTM A194

Material Selection Guide by Corrosion Zone

Why Choose SINOFASTENER for Ship Fasteners

Standards Reference

FAQ

Q1: What is the difference between marine grade fasteners and regular fasteners?

Marine grade fasteners differ from regular industrial fasteners in three key respects. First, corrosion protection is mandatory — hot-dip galvanizing per ISO 1461 or A4 (316) stainless steel per ISO 3506-1, rather than plain or lightly oiled finish. Second, anti-loosening performance is required due to continuous vessel vibration — spring washers per DIN 127 or prevailing torque nuts are standard. Third, material traceability through EN 10204 3.1 certificates is required by classification societies for primary structural and pressure-boundary connections, whereas general industrial fasteners typically do not require certified material documentation.

Q2: Which material is best for ship fasteners — galvanized carbon steel or stainless steel?

The selection depends on the corrosion zone. For dry interior spaces and engine room general service, zinc-plated or HDG carbon steel Grade 8.8 is sufficient and cost-effective. For weather deck and exterior equipment, HDG carbon steel per ISO 1461 with 70 μm minimum coating provides proven protection in C4 environments. For splash zones and submerged service such as ballast tanks and hull appendages, A4-70 or A4-80 (316/316L) stainless steel per ISO 3506-1 is specified because the chromium-nickel-molybdenum alloy provides pitting resistance in chloride-containing seawater. Per ISO 12944, C5-M (very high marine) environments require either HDG with duplex coating or stainless steel.

Q3: What standards apply to shipbuilding fasteners?

Ship fasteners are governed by a combination of international product standards and classification society rules. ISO 4014/4017 and ISO 898-1 cover hexagon bolts and mechanical properties. ASTM A193/A194 govern high-temperature and pressure bolting for engine room and piping systems. DIN standards (DIN 127 washers, DIN 3570 U-bolts, DIN 580 eye bolts) cover specialized marine hardware. EN 14399/EN 15048 apply to structural bolting assemblies. Classification society rules — IACS UR S26 for hull structural bolting and individual class rules (ABS, DNV, LR, BV, CCS) — impose additional certification and traceability requirements beyond the product standards themselves.

Q4: Can SINOFASTENER supply complete fastener kits for a shipbuilding project?

Yes. SINOFASTENER supplies project-based fastener kits assembled by ship zone, hull block, or system. Each kit contains matched bolt-nut-washer sets sorted by size and property class, labeled with part numbers and heat numbers, and packaged to the shipyard's warehouse receiving specification. Complete EN 10204 3.1 certification packages are provided with each shipment, and third-party or classification society inspection can be arranged at the manufacturing stage. Our annual capacity of 50,000 tons supports both new construction series and urgent repair vessel requirements.