What is Duplex Stainless Steel Grade 2205 for External Glass Balustrades

There are many factors to consider when purchasing a glass balustrade and one of the top priorities is how durable it is both in terms of it’s appearance and its safety.  External glass balustrades can offer a stylish, elegant, and sophisticated touch to a variety of build designs whilst maximising natural light and making an area feel more spacious.  The use of toughened glass also makes them just as safe as other balustrade designs and much easier to maintain.  However, both aesthetic looks and safety can be affected if the components used to hold the glass panels in place are not suited to the specific installation scenario.  This may include the geographic location of the property, it’s immediate environment, and what the glass balustrade is fixing in to.  Stainless steel is one of the most common materials used with glass to create striking  glass balustrade designs.  For external glass balustrades, either grade 316 or grade 2205 stainless steel should be used, however it is important to know their differences in order to make an informed decision.  These will be discussed here.

External glass balustrades on a decking space

Both grade 316 and 2205 stainless steel have been classified as marine grade making them suitable for use in coastal locations or other areas where excessive chloride is present.  However marine grade 2205 duplex stainless steel contains higher levels of Chromium, Nickel, Molybdenum, and Nitrogen.  This results in a stronger product with almost double the corrosion resistance of marine grade 316 stainless steel.    To give you a good idea of it’s durability, marine grade 2205 is often used on oil rigs and for marine propeller shafts.  It is less likely to suffer from fatigue corrosion, stress corrosion cracking, chloride pitting and crevice corrosion, and sulphide stress corrosion.  Therefore, if used for external glass balustrades, marine grade 2205 would add longevity to your balcony, decking area, terrace, or other outdoor space.  It would look its best for longer whilst maintaining its purpose of providing an effective safety feature.

Another difference between the two stainless steels is within their microstructures.  Grade 316 has an austenitic microstructure (consisting of austenite, which is a non-magentic solid solution of iron with an alloying element).  Grade 2205 stainless steel has as a ferritic-autentistic microstructure (consisting of 50% ferrite and 50% austenite, hence the term Duplex).  Due to the their ferrite content, Grade 2205 stainless steels are magnetic, and the duplex structure makes for higher strength balustrade systems, with higher resistance to stress corrosion cracking.

Curved Mini-Post external glass balustrades

At Elite Balustrade Systems, we pride ourselves on creating outdoor living solutions that not only look great, but ones which are designed to last.  We have therefore committed to manufacturing most of our product range with duplex marine grade 2205 stainless steel from mid August 2017.  Whilst marine grade 316 stainless steel is still commonly used in areas with high chloride levels, it cannot be considered as corrosion proof in all situations and may be prone to localised pitting and crevice corrosion.  Pitting is a process where small cavities or holes develop on a surface over a period of time which can be very difficult to detect or prevent against.  Crevice corrosion occurs at the gaps between parts, under gaskets or seals, and inside cracks and seams.  Furthermore, its not only chloride levels that can determine risks of corrosion in grade 316 stainless steel.  Humidity levels, temperature, and pollution levels should also be considered.

External glass balustrades for a balcony

It is for these reasons that we are choosing duplex marine grade 2205 stainless for our customers.  We want them to enjoy their shiny and safe external glass balustrades for as long as possible with little required maintenance.  Modern life is complicated.  The customer experience shouldn’t be!

If you would like further information about our external glass balustrades, please do not hesitate to contact us.  You can reach us by phone on 01254 825594, or email sales@elitebalustrade.com . Alternatively request a call back or send us an enquiry via our website.  We look forward to hearing from you.



Published: 26th July 2017

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