A4 Marine Grade Fasteners

Shop Now

A4 marine grade fasteners are specifically designed for use in harsh environments where corrosion resistance is essential. Manufactured from stainless steel AISI 316, these fasteners provide superior protection against saltwater, coastal air, chemicals and high humidity.


At Duchy Fasteners, a comprehensive range of A4 marine grade fastenings is held in stock, supporting projects across Cornwall and throughout the UK. Customers can purchase directly from the trade counter or order online for nationwide courier delivery, ensuring easy access to marine grade fixings when reliability matters most.

What Are A4 Marine Grade Fasteners?

A4 marine grade fasteners are produced from AISI 316 stainless steel, an austenitic alloy that includes chromium, nickel and molybdenum. The addition of molybdenum is what sets A4 apart from standard stainless grades, significantly improving resistance to chloride corrosion.

This makes A4 fasteners suitable for environments where saltwater exposure, sea air or chemical contact would cause lower grade metals to corrode. Because of this enhanced performance, A4 stainless steel is commonly referred to as marine grade stainless steel.

These fasteners are widely specified for coastal construction, marine engineering, agricultural installations and industrial applications where long-term durability is critical.

Shop Now

Stainless Steel Fastenings A4 316
Stainless Steel Fastenings A4 316
Steel Self Colour
Steel Self Colour Fastenings
Galvanised Fastenings Duchy Fasteners
Galvanised Fastenings
Zinc Plated Fastenings
Zinc Plated Fastenings
Brass Fastenings Duchy Fasteners
Brass Fastenings

A4 Marine Grade Fasteners Held in Stock

Duchy Fasteners stocks a broad and practical selection of A4 marine grade fastenings to meet the needs of professional users and private customers.


The A4 marine grade range includes:

  • Screws including countersunk, pan head, socket head and self-tapping screws

  • Bolts including hex bolts, socket cap screws, coach screws and cup square bolts

  • Nuts including full nuts and specialist thread options

  • Washers including flat washers and spring washers

  • Pins including dowel pins and retaining pins

  • Machine screws and precision socket fasteners

These fasteners are available in a wide range of metric sizes and thread types, allowing complete fastening solutions to be sourced from one supplier.

Designed for Marine and Coastal Environments

Marine and coastal environments place constant stress on metal components due to salt exposure and high humidity. Chlorides present in sea air and seawater can quickly degrade standard steel and lower grade stainless steel fasteners.


A4 marine grade fasteners are designed to withstand these conditions. Their enhanced corrosion resistance helps prevent surface pitting, rust staining and long-term weakening of fixings.


This makes them ideal for use in harbours, marinas, boat fittings, coastal buildings and outdoor structures located near the sea. In regions like Cornwall, where salt-laden air is common, A4 marine grade fasteners provide a dependable long-term solution.

Strength and Performance Characteristics

A4 marine grade fasteners offer similar mechanical strength to other stainless steel fasteners while providing significantly improved corrosion resistance. They are not classed as high tensile fasteners but offer sufficient strength for a wide range of applications where environmental exposure is the main concern.


These fasteners maintain performance across a broad temperature range and offer good resistance to vibration and fatigue. This makes them suitable for installations subject to movement, weather exposure and repeated loading.


For projects requiring extreme load bearing capacity, high tensile steel fasteners may be more appropriate, but for corrosive environments A4 marine grade fasteners are the preferred choice.

Typical Uses for A4 Marine Grade Fasteners

A4 marine grade fasteners are commonly specified in applications such as:


  • Marine construction and boat building

  • Coastal and waterfront buildings

  • Agricultural installations exposed to weather

  • Food processing and hygienic environments

  • Industrial and chemical processing facilities

In these settings, the long service life of A4 stainless steel helps reduce maintenance requirements and replacement costs over time.

Trade Counter Supply in Cornwall

Local customers can purchase A4 marine grade fasteners directly from the Duchy Fasteners trade counter at Cornwall Business Park. This allows trade professionals to inspect products, confirm sizes and collect fasteners immediately.


The trade counter is ideal for urgent jobs and ongoing site work where correct specification and fast access to stock are essential. Knowledgeable staff are available to assist with selecting suitable marine grade fasteners based on environment and application.

Online Ordering and UK Delivery

For customers outside Cornwall or those who prefer remote purchasing, A4 marine grade fasteners can be ordered online for courier delivery across the UK.


Online ordering provides access to the same extensive stock range held at the trade counter, making Duchy Fasteners a practical supplier for national projects, maintenance teams and repeat trade customers.


This combination of local service and national delivery ensures consistent availability wherever projects are based.

Trade Counter Supply in Cornwall

Local customers can purchase A4 stainless steel fasteners directly from the Duchy Fasteners trade counter in Scorrier. This allows customers to inspect products, confirm specifications and collect fasteners immediately.


The trade counter is particularly useful for urgent projects and ongoing site work where quick access to the correct fixings is essential. Experienced staff are available to help identify suitable fasteners based on application and environment.

Why Choose Duchy Fasteners for A4 Marine Grade Fixings

Duchy Fasteners offers extensive stock holding across stainless steel grades, including a wide selection of A4 marine grade fasteners. This depth of stock allows customers to source screws, bolts, nuts, washers and pins from one supplier without compromising on specification.


With the option to buy locally or online, customers benefit from flexibility, reliability and consistent quality. This makes Duchy Fasteners a trusted choice for marine grade fixings in Cornwall and throughout the UK.

FAQs About A4 Marine Grade Fasteners

What does marine grade stainless steel mean?

Marine grade stainless steel refers to A4 or AISI 316 stainless steel, which contains molybdenum for improved corrosion resistance.

Are A4 fasteners suitable for coastal environments?

Yes, A4 marine grade fasteners are specifically designed for coastal and salt-exposed environments.

What A4 marine grade products do Duchy Fasteners stock?

Duchy Fasteners stocks A4 screws, bolts, nuts, washers, pins and machine screws in various sizes.

Can I buy A4 marine grade fasteners locally in Cornwall?

Yes, A4 marine grade fasteners are available from the Duchy Fasteners trade counter in Scorrier.

Do you offer UK delivery on A4 fasteners?

Yes, A4 marine grade fasteners can be ordered online and delivered nationwide.

Should I choose A4 instead of A2 near the sea?

For coastal and marine environments, A4 marine grade fasteners are strongly recommended over A2.

How Does This Affect Your Fixings Choice?

Selecting A4 marine grade fasteners ensures long-term reliability in environments where corrosion is a constant challenge. By choosing the correct stainless steel grade and sourcing from a supplier with extensive stock, projects benefit from durability, safety and reduced maintenance.


Whether purchasing locally in Cornwall or ordering online for UK delivery, Duchy Fasteners provides dependable access to marine grade A4 stainless steel fastenings designed to perform in the toughest conditions.