How to clean and maintain Stainless Steel

by Natasha Christou Digital Marketing Consultant

Stainless Steel is by far the most corrosion resistant metal widely available for use in Cable Management Systems, with varying grades that offer different levels of overall protection. However, contrary to popular belief, Stainless Steel can rust if not maintained or installed correctly.

In this article, Electrix International Ltd aim to give you a good understanding of Stainless Steel and how best to maintain a corrosion free installation.

Stainless Steel – A Brief Overview

To understand how to correctly maintain your installation, it is important to understand what makes Stainless Steel such a sought-after material.

Most other metals are very susceptible to corrosion, recognised quickly on mild steel and iron as unsightly orange/yellow rust. Metals like these are “active” because they actively corrode when their atoms react with oxygen, which can quickly form rust.

Stainless Steel is known as a “passive” metal because it contains other metals that stabilise the atoms (Chromium and Nickel in the case of 304 – 1.4301 – V2A and 316 – 1.4404 – V4A grades). During the manufacture of the steel, a small amount of the Chromium in the alloy reacts with oxygen to naturally form a passive Chromium-rich oxide layer on the surface of the steel. This invisible layer protects the steel, and is self-renewing. When this layer is intact the metal is passive and therefore “Stainless”, offering excellent levels of corrosion resistance. When this layer is broken, although it is very quick to self-renew, there is a small window of opportunity when the surface is said to be in the “active” state that could allow unwanted irritants to make contact with the steel underneath and start the corrosion process.

There are several best practices to follow to avoid corrosion issues occurring with your installation.

The Four Enemies Of Stainless Steel

There are four “enemies” of Stainless Steel that can break down the protective layer and allow corrosion to occur. However, you can reduce the likelihood of any of these being a problem by following the best practice that is set out a little later in this post.

1.      Chlorides / Chlorine - 
Chlorides are found in some industrial and household cleaners, and of course, chlorine is commonly found in environments such as swimming pools. The use of chlorides in cleaning, or the proximity of Stainless Steel to chlorine, can break down the protective “passive” layer but there are best practices to follow to reduce the risk of such occurrences

2.      Mechanical Abrasion -
i.e. Things that will scratch the surface of the steel, such as wire brushes, steel pads and scrapers. Soft cloths and plastic scouring pads are recommended as a safe alternative.

3.      Hard Water - 
Hard water is water that is considered to have high mineral content. This can be found all over the world, with the mineral content of water changing from one place to the next. Hard water may leave spots on Stainless Steel and, when heated, leave deposits behind that if allowed to remain, will break down the passive layer and rust Stainless Steel.

4.       

5.      Other Deposits -
Other deposits from food preparation and service must be properly removed. This is not really relevant to the use of Stainless Steel in Cable Management, but worth noting nonetheless.

Best Practice

None of the information above should be considered a reason not to use Stainless Steel in your cable management installation. After all, it is far superior in corrosion resistance, finish and aesthetics to other metals and plastics. The best practice set out below should go a long way to ensuring that your installation remains in pristine condition for many years.

1.      Use the correct tools - 
When cleaning Stainless Steel products, use non-abrasive tools. Soft cloths and plastic scouring pads will not harm the steel’s passive layer. Stainless Steel pads can, on occasion, be used but the scrubbing motion MUST be in the direction of the manufacturers’ polishing marks.

2.      Clean with the polish lines - 
Some Stainless Steel comes with visible polishing lines or “grain.” When visible lines are present, always scrub in a motion parallel to the lines. When the grain cannot be seen, play it safe and use a soft cloth or plastic scouring pad.

3.      Use alkaline, alkaline chlorinated or non-chloride containing cleaners -  
While many traditional cleaners are loaded with chlorides, the industry is providing an ever-increasing choice of non-chloride cleaners. If you are not sure of the chloride content in the cleaner used, contact your cleaner supplier. If your present cleaner contains chlorides, ask your supplier if they have an alternative. Avoid cleaners containing quaternary salts; it can also attack Stainless Steel and cause pitting and rusting.

4.      Treat your water - 
Though this is not always practical, softening hard water can assist in reducing deposits. There are various filters that can be installed to remove distasteful and corrosive elements. To ensure proper water treatment, call a treatment specialist.

5.      Keep your food processing equipment clean - 
Use alkaline, alkaline chlorinated or non-chloride cleaners at their recommended strength. Clean frequently to avoid build-up of hard, stubborn stains. If you boil water in Stainless Steel equipment, remember the single most likely cause of damage is chlorides in the water. Heating cleaners that contain chlorides have a similar effect.

6.      Rinse, rinse, rinse -
If chlorinated cleaners are used, thoroughly rinse and wipe the equipment dry immediately. The sooner you wipe off standing water, especially when it contains cleaning agents, the better. After wiping equipment down, allow it to air dry; oxygen helps maintain the Stainless Steel’s passivity film. In environments where it is not possible to wipe down standing water, such as in Marine / Offshore industries, the use of 316 – 1.4404 – V4A grade Stainless Steel is recommended to reduce the risk of corrosion.

7.      Never use hydrochloric acid (muriatic acid) on Stainless Steel - 
Hydrochloric acid is classed as reducing acid and lacks the oxidising properties that Stainless Steels need to maintain their ‘passive’ corrosion resistant surface layer, so when hydrochloric acid is present in any ‘external environment’ corrosion is promoted.

8.      Improve ventilation in chlorine rich environments - 
If your Stainless Steel is used in environments such as swimming pools where chlorinated condensation may be present, it is wise (as an extra precaution to the cleaning methods shown above) to improve ventilation around the installation, which should further reduce the chance of pitting or staining occurring. It is also highly recommended that you use 316 – 1.4404 – V4A grade in an environment like this.

9.      Restore / Passivate Stainless Steel - 
Stainless Steels are designed to naturally self-passivate whenever a clean surface is exposed to an environment that can provide enough oxygen to form the chromium rich oxide surface layer on which the corrosion resistance of these alloys depends. Naturally occurring conditions such as air or aerated water will do this and so under many exposure conditions Stainless Steels will naturally self-passivate. In some environments, however, it may be necessary to manually passivate the Stainless Steel. Refer to www.bssa.org.uk/topics.php?article=68 for more information

As with all information of this nature, you can never 100% guarantee that corrosion will not occur in your installation, but if the best practices are followed and you are using the correct grade of Stainless Steel for your installation environment you are highly unlikely to ever see corrosion issues. Rest assured that Stainless Steel is by far the most corrosion resistant material of all of the commonly used metals.

 

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Created on Jun 16th 2020 10:57. Viewed 421 times.

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