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Product Advice: Steel fixing finishes

As a leading supplier of fixings, fastenings and general support solutions, the team at Armaflo are frequently asked one key question.  What steel fixing finishes do I need and why? In this blog, we answer this question once and for all; explaining the key differences between Bright Zinc Plated (BZP), Hot Dipped Galvanised (HDG) and A2/A4 stainless steel fixings. Check it out!

Before we delve into our advice, let’s take a look at what metal finishing entails and how it can provide real advantages to Armaflo customers. 

What is Metal Finishing?

It’s simple: metal finishing is a broad-reaching term that is used to describe the process of ‘coating’ the surface of a metallic part, commonly referred to as a substrate. In other cases, finishing can also entail and process which aids in the polishing, cleaning or general improvement of a surface. 

In the majority of cases, metal finishing will consist of electroplating.  A complex process in which metal ions or effectively deposited onto a substrate by way of an electrical current.

What are the Benefits of Metal Finishing?

Industrial metal finishing has a number of benefits which are particularly relevant in the world of fixings, fastenings and general support solutions. Whilst the list goes on, we’ve identified some of the major advantages behind metal finishing:

  • Metal finishing can act as a primer coat to facilitate the adhesion of paint; 
  • Finishing can fortify the substrate and enhance its resistance to wear;
  • The process can reduce the impact of friction and corrosion; 
  • Metal finishing can vastly improve the aesthetic appearance of a part;
  • The process can ease the solderability of a part; 
  • Improved chemical resistance; 
  • Facilitate electrical conduction; and
  • Clean, polish & remove surface defects to a very high standard.

Put simply, metal finishing can bring the fortification and durability of any given part to a whole new level, adding a level of security to any support system that they’re a part of. But what separates these different kinds of finishes, especially where steel fixings are concerned?

BZP, HDG and A2/A4: Understanding the Differences

Here at Armaflo, we offer steel fixing finishes in 3 options: Bright Zinc Plated (BZP), Hot Dipped Galvanised and A2/A4 Stainless Steel. To help our customers make the right decision on what kind of finish is right for them, we’ve broken down those key finishes below. Keep reading to learn more!

① Bright Zinc Plated (BZP)

A Bright Zinc Plated (BZP) finish is one of the most popular choices for stainless steel fixings and can be seen in the picture above. BZP involves a process where a thin layer of zinc is applied to the substrate (in this case, stainless steel) using an electrical current. 

By galvanising the stainless steel in this way, the chances of rusting or oxidation are totally eliminated. However, it is important to note that whilst the zinc will make your fixing resistant to moisture, this protection will quickly wear off if it is being used in an outdoor environment. 

There are a few advantages to consider here:

  • BZP is a low-cost finish which is often freely available;
  • BZP makes your fixings look nice and shiny, enhancing their aesthetic appeal; and 
  • This finish is incredibly easy to work with; installation is a breeze!
② Hot Dip Galvanised (HDG)

Hot Dip Galvanising (HDG) is a metal finishing process which is slightly more complicated than Bright Zinc Plating. Whilst BZP involves applying a layer of zinc using an electrical current, HDG involves ‘dipping’ fixings and fasteners in a bath of molten zinc, providing a thick and durable protective layer. 

Where weather resistance is a priority, HDG is one of the most cost-effective and high-performance options available. However, it’s important to remember a key disadvantage here, that being that the size of the thread will increase due to that thick layer of zinc. So, if you’re using HDG fasteners, make sure you’re using them across all areas of the job (HDG fasteners have an oversize tap which accommodates that extra layer of zinc – nifty, right?). 

Yes, HDG isn’t as aesthetically pleasing as BZP. However, it offers a level of corrosion protection which is extremely impressive. Let’s look at a breakdown of the advantages of HDG:

  • Low maintenance thanks to its high level of corrosion resistance; 
  • HDG is suitable for outdoor applications; and
  • Cost-effective (but a little more expensive than BZP).
③ A2 & A4 Stainless Steel

If you need something that’s both extremely durable as well as aesthetically pleasing, opting for an A2 or A4 Stainless Steel finish could be the answer you’ve been looking for. 

Unlike any other sheet metal out there, stainless steel is famous for its impressive strength and corrosion resistance. This is partly thanks to its chromium content (10.5%) which helps the steel resist corrosion. It’s no wonder why A2 and A4 stainless steel are applied to fixings and fasteners the world over. 

Unlike carbon steel, for example, A2 and A4 stainless steel form a passive film of chromium oxide.  This prevents corrosion and rust from settling into its structure. 

The unbeatable levels of resistance offered by A2 & A4 stainless steel finishes make them the perfect choice for outdoor applications.  Especially where your customer might want something that’s a bit more aesthetically pleasing. The only possible drawbacks to mention here are that these options are more expensive and they can be a little more difficult to work with. Check out the benefits of A2 & A4 stainless steel below:

  • The highest possible degree of strength & corrosion resistance;
  • An aesthetically pleasing finish; and
  • Can be used in chemical & marine environments. 
Need a Specific Steel Fixing Finish? You Can Count on Armaflo 

We’re passionate about connecting our growing customer community with the perfect product to save time, money and hassle.  Contact a member of our helpful team to discuss the options for stainless steel fixings finishings. We look forward to hearing from you!


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