Stainless Steel A4 AISI 316 Fasteners

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Stainless steel A4 AISI 316 fasteners are designed for demanding environments where corrosion resistance is critical. At Duchy Fasteners, a comprehensive range of A4 stainless steel fixings is held in stock to support projects exposed to coastal air, saltwater, chemicals and high humidity.


Operating from Cornwall Business Park, Duchy Fasteners supplies A4 stainless steel fasteners to local trade customers through its trade counter and to customers across the UK via courier delivery. This makes it easy to source marine grade fixings whether you are working locally in Cornwall or managing projects nationwide.

What Is Stainless Steel A4 AISI 316?

Stainless steel A4 is the ISO classification for AISI 316 stainless steel fasteners. This grade is an austenitic stainless steel alloy that includes chromium, nickel and molybdenum. The addition of molybdenum significantly improves resistance to corrosion, particularly in environments containing chlorides.


A4 stainless steel is often referred to as marine grade stainless steel because of its ability to withstand saltwater exposure and coastal conditions. It also performs well in industrial environments where chemicals or acidic substances may be present.


This enhanced resistance makes A4 stainless steel the preferred choice for applications where longevity and reliability are essential and where lower grades may deteriorate over time.

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Stainless Steel A4 Fasteners Held in Stock

Duchy Fasteners stocks a wide and practical range of stainless steel A4 AISI 316 fastenings to meet the needs of professional users and private customers.


The A4 stainless steel 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 range of metric sizes and thread configurations, allowing customers to source compatible components for complete assemblies from a single supplier.

Why Choose A4 Stainless Steel Fasteners

A4 stainless steel fasteners are specified when corrosion resistance is more important than cost alone. The inclusion of molybdenum allows A4 fasteners to resist pitting and surface degradation caused by salt and chemicals.


This makes A4 fasteners particularly suitable for coastal construction, marine engineering, agricultural settings and industrial installations. In areas such as Cornwall where salt-laden air is common, A4 stainless steel provides greater long-term reliability than A2 grades.


Choosing A4 stainless steel helps reduce maintenance requirements and minimises the risk of fastener failure caused by corrosion.

Corrosion Resistance in Marine and Coastal Environments

The defining feature of A4 stainless steel is its ability to perform in harsh environments. Chlorides found in seawater and coastal air can rapidly attack lower grade metals, leading to rust and structural weakness.


A4 stainless steel resists this type of corrosion, maintaining its surface integrity and strength over extended periods. This makes it suitable for outdoor installations near the sea, boat fittings, harbours, coastal buildings and exposed infrastructure.


For any project where salt exposure is unavoidable, A4 stainless steel is the recommended choice.

Strength and Mechanical Performance

Stainless steel A4 fasteners offer similar mechanical strength to A2 stainless steel fasteners. While not classified as high tensile, they provide sufficient strength for a wide range of applications where corrosion resistance is the primary concern.


A4 fasteners also offer good toughness and resistance to fatigue, making them suitable for environments subject to vibration or movement. Their performance remains consistent across a wide temperature range, adding to their versatility.


Where extreme load bearing is required, alternative high tensile grades may be considered, but for corrosive environments A4 offers the best balance of strength and durability.

Typical Applications for A4 Stainless Steel

A4 stainless steel fasteners are commonly used in applications such as:


  • Marine construction and boat building

  • Coastal buildings and outdoor structures

  • Agricultural installations

  • Food processing and hygienic environments

  • Chemical and industrial facilities

In each of these settings, the superior corrosion resistance of A4 stainless steel helps ensure long service life and reduced maintenance.

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.

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.

Online Ordering and UK Delivery


For customers outside Cornwall or those who prefer remote purchasing, A4 stainless steel fasteners can be ordered online with courier delivery across the UK.


This service provides access to the same extensive A4 stock range held at the trade counter, making Duchy Fasteners a practical choice for national projects, maintenance teams and repeat trade supply.

Why Buy A4 Fasteners from Duchy Fasteners

Duchy Fasteners combines extensive stock holding with local expertise and national delivery capability. By carrying a wide selection of A4 stainless steel screws, bolts, nuts, washers and pins, the company supports projects where reliability is critical.


The ability to purchase locally or online provides flexibility without compromising on quality or availability. This makes Duchy Fasteners a dependable supplier for marine grade fixings in Cornwall and across the UK.

FAQs About Stainless Steel A4 AISI 316 Fasteners

What does A4 mean in stainless steel fasteners?

A4 is the ISO designation for AISI 316 stainless steel, which includes molybdenum for enhanced corrosion resistance.

Are A4 fasteners suitable for marine environments?

Yes, A4 stainless steel is commonly used in marine and coastal applications due to its resistance to saltwater corrosion.

What types of A4 fasteners do Duchy Fasteners stock?

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

Can I buy A4 fasteners locally in Cornwall?

A4 stainless steel fasteners are available from the Duchy Fasteners trade counter in Scorrier.

Do you deliver A4 fasteners across the UK?

Yes, A4 fasteners can be ordered online and delivered nationwide by courier.

Should I choose A4 instead of A2 in coastal areas?

For coastal or salt-exposed environments, A4 stainless steel is strongly recommended over A2. Especially if you want to avoid rust stain.

How Does This Affect Your Fixings Choice?

Selecting stainless steel A4 AISI 316 fasteners ensures long-term performance in environments where corrosion is a serious concern. By choosing the correct 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 access to a comprehensive range of marine grade A4 stainless steel fastenings designed to perform where it matters most.requirements with confidence.