The below article is an excerpt from our eBook “Maintaining Your Stainless Steel Installation”. To download the full eBook, sign up for the Electrix Newsletter on the sign up form in the sidebar / footer of this page.
To understand how to correctly maintain your Stainless Steel 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 316L – 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.
The Four Enemies Of Stainless Steel
- 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.
- 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.
- 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.
- Other Deposits – Other deposits from food preparation must be properly removed. This is not really relevant to the use of Stainless Steel in cable management but worth noting nonetheless.
Follow best practice to avoid corrosion occurring within your installation.
None of the information above should be considered a reason not to use Stainless Steel in your cable management installation. After all, it’s corrosion resistance, finish and aesthetics make it a far superior material when compared 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.
- 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.
- 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.
- 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.
- Rinse, rinse, rinse – If chlorinated cleaners are used, thoroughly rinse, wipe and dry equipment and supplies 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 316L – 1.4404 – V4A grade Stainless Steel is recommended to reduce the risk of corrosion.
- 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.
For more information and other helpful tips, please download the eBook “Maintaining Your Stainless Steel Installation” by signing up for the Electrix Newsletter in the sidebar / footer of this page.