A2, A4 & A8 (1.4529 HCR) Stainless Steel Bolts, Screws, Fasteners and Fixings

Stainless steels are available in a number of different grades that are often found within the fastener industry, used in screws, nuts, bolts and other fixings.

See our range of stainless steel fasteners here

There’s a number of exceptional types of stainless steel with A2 and A4 being the most popular.
Types 301, 303, 309, 312, 317, 321 and 410 all offer very distinct properties, including temperature resistance, affordability, corrosion resistance and ductility.

AL-6XN is a weldable type of stainless steel offering excellent resistance to stress corrosion cracking and exceptional general corrosion resistance. Alloy 926 and Alloy 255 SMO also share these properties while providing additional resistance to crevice and pitting corrosion.

A2 Stainless Steel Bolts & Fasteners

A2 stainless steel fixings are made from an alloy containing a mixture of two or more metals.

The steel within the fixing must contain at least 10.5% chromium to be considered or called stainless, and this chromium makes the metal more corrosion resistant and less likely to stain than other steels. The corrosion resistance is created by steel forming a layer of chromium oxide.

These fasteners often contain molybdenum, titanium, nickel or copper for enhanced or increased properties such as strength, corrosion resistance and formability.

A2 stainless steel fasteners can be found across a number of industries including hospitality and medical. Sometimes referred to as ‘Type 304 Stainless Steel‘, it is made out of 18% chromium and 8% nickel.

A4 Stainless Steel Bolts & Fasteners

There is no evident visual difference between A2 and A4 stainless fasteners steel as they are both polished using the same process – but there are characteristics that provide a difference.
Otherwise known as ‘Type 316 Stainless Steel‘, A4 stainless steel contains carbon, silicon, manganese, phosphorous, sulphur, chromium, molybdenum, and nickel. These elements make fixings manufactured from A4 steel very resistant to corrosion and less reactive to other materials.

A4 stainless steel fasteners are typically known as marine grade stainless fasteners due to their resistance to salt water corrosion and can be found in a number of water-based applications. It is also resistant to salt spray.

A4 stainless fasteners are easier to fabricate, clean, finish and weld, and whilst they are generally more expensive than A2 fasteners, they can be more cost-effective over a longer period of time due to the lack of maintenance or replacement required when used outside.

A4-70 Stainless Steel Fasteners

Stainless steel grade A4-70 is often used in surgical instruments, due to its non-reactive qualities and corrosion resistance.
A4-70 is an austenitic, acid proof stainless grade, cold worked to provide a minimum tensile strength of 700 MPa.

Security fixings manufactured from A4-70 stainless are popular for securing medical equipment, and our range of 5-lobe pin TX security screws are a popular choice.

A8 Stainless Steel Bolts & Fasteners (High Corrosion Resistant Fasteners)

A8 stainless steel, or 1.4529 HCR steel, is a further improvement on the stainless steel grades mentioned above. It features a higher molybdenum and nitrogen content which provides excellent general corrosion resistance.

In particular, stainless steel A8 offers high resistance to stress corrosion cracking, crevice corrosion and pitting. Fixings in grade A8 also host good mechanical and polishing properties, while being suitable for use in a wide range of temperatures and environments.

Here at Fastenright, we supply a variety of high corrosion resistant fasteners made of A8 stainless steel. This includes a range of screws, bolts, nuts and washers – such as the popular 1.4529 hex socket cap screws and threaded rods.

Other materials and finishes are available, click here for details.

If you require more information or would like to enquire further, please send us your requirements.

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