Select Page

Insight From Top Steel Suppliers UK

Why is Stainless Steel Stainless?

Insight From Top Steel Suppliers UK

Why is Stainless Steel Stainless?

by | Feb 21, 2017 | Stainless Steel, Steel

As respected stainless steel suppliers in the UK, it’s our job to know our subject inside out. If you’ve ever wondered exactly what makes stainless steel stainless, here’s the answer.

It’s a chromium thing

Put simply, stainless steel contains at least ten and a half percent chromium, according to the British and European standard, and that’s what makes it stainless. But look deeper and it isn’t quite that simple. The thing is, the metal isn’t made of a specific grade of steel but a broad family of iron alloys that all contain the 10.5% of chromium required by the EU.

If you add more than 10.5% chromium the stainless properties are even better. Most grades of steel we supply have 17% or so chromium and some steels come with as much as 26% chromium, designed for particularly harsh environments.

Atomic magic – The world of the very, very small

Look at stainless steel from an atomic perspective and things get even more interesting. Chromium and iron atoms are about the same diameter, about 0.25 nanometres. This means they can intermingle easily, with the chromium uniformly dispersed through the metal. When they’re exposed to oxygen the chromium atoms form a thin oxidised layer called a passive film, around 15 nanometres thick. This sticks fast and is remarkably inert. And whenever there’s oxygen present, any damage to the layer is instantly repaired to deliver a stainless surface.

Completely stainless? Not always…

Having said all that, in a way the term ‘stainless’ steel is a bit of a misnomer, since it can actually stain. The protective chromium oxide layer than forms on the surface of the metal can be scratched and damaged. It usually repairs itself by reacting with oxygen. But when it comes in contact with an aggressive reagent or is stored in a non-oxidising environment, staining can happen. You can also use other alloys to make stainless steel. Nickel, for example, creates different properties, making the metal non-magnetic without having to heat treat it.

If you heat stainless steel it can also discolour, this time thanks to uneven oxidisation. Sometimes you get an attractive rainbow effect because of interference to reflected light, something you also get in Titanium, loved by jewellers for its remarkable beauty.

How was stainless steel discovered?

As it happens, the discovery of this incredibly useful metal was a happy accident. Roll back time to the years just prior to the First World War, when a man called Harry Brearley was busy searching for ways to make a very high temperature, wear-resistant steel for making gun barrels, since the corrosive explosive cordite in gunpowder kept wearing them out.

Harry tried alloying iron with chromium but it was a frustrating task – whatever he did, he ended up with an annoyingly shiny surface that resisted every attempt to scratch it with acid to reveal the crystalline structure below. It took a while for him to have that magical Eureka moment, but he eventually realised he’d unwittingly created a steel it was almost impossible to stain. And his discovery changed our world.

Today stainless steel is used for cutlery, microwaves, washing machine drums, cladding, chemical tankers in shipping, catering gear, water treatment, nuts and bolts, exhaust systems, surgical implants, and countless more essential applications.

If you’re looking for expert steel suppliers in the UK, you’ve found us. We’ll be happy to help with all your metal supply needs.

Please complete the enquiry form located on this page, call +44 (0) 330 223 2653 or email us to discover how we could be supplying you with premium metal products and professional metal processing services.

The latest from the blog.

Costly copper, rejected mines, tough emissions targets, and cool aluminium research

Copper prices have soared. The Philippines has rejected plans for a massive new copper and gold mine.  Brass is proving more desirable than anyone imagined in New Zealand. There's an innovative new way of recycling aluminium on the cards. One Brazilian mining firm is...

Canada steel tariffs, copper demand soars, steel plant delays, and more

Canada has slapped a bunch of retaliatory tariffs on American aluminium products following Trump's tariffs on Canadian aluminium. Copper is set to benefit from a slew of new and innovative green energy projects. New steel plants are delayed in Canada, worldwide steel...

Metal Suppliers News – Life on Earth, 3D Steel Printing and more

Every living being on earth might have nickel sulphide to thank for its existence – including us. The US Army will soon be 3D printing super-tough steel components and weaponry. Copper is proving its worth as a powerful disinfectant. Rio Tinto and New Zealand are...

UK industry steps up to supply aluminium for medical products

Metalex Products is currently working overtime at its sites in Poole, Horsham, Birmingham, Chepstow and Milton Keynes to process orders for aluminium plate and bar billets being used in the rapid production of medical equipment.Metalex Products working overtime. As...

Metalex Aluminium Suppliers – Focus Aluminium – Predictions for 2020

Metalex products – Focus aluminium – Predictions for 2020 We all operate in a global economy these days. No company, person or country is an island, Metalex included, and global issues are having an impact in all sorts of ways, some expected and others unexpected....

Weird metals – Meet lasered lead, Gallium, Cuprates, Kagome and more.

Weird metals – Meet lasered lead, Gallium, Cuprates, Kagome and more Metals can be weird. Very weird. This time around, to welcome you to 2020, we thought we'd take a look at some of the oddest, most extraordinary metals around. Here's to an exceptional, profitable,...

Metal Supplies UK news: Trump, tariffs, ‘green’ aluminium and more

Our world is a place of dramatic highs and lows right now. As aluminium suppliers we're pleased to see the industry cleaning up its act so quickly in the face of runaway climate change. As carbon steel suppliers we're watching what's happening to the British Steel...

Focus Aluminium – How great eco-credentials are driving a bright future

Focus Aluminium – How great eco-credentials are driving a bright future for Aluminium. As aluminium stockists we're always on the look-out for news about the metals we sell. This time around we've created an aluminium special, since the metal has such good 'green'...

Brilliant Aluminium batteries, Steel slumps, nickel shortages and more

As providers of aluminium supplies it's fascinating to see exciting new developments happening in the sector. Steel is also on the move, with innovations taking place left, right and centre despite the current slump in demand. Here's the news, from our world to yours....

British Steel deal, ongoing Trade Wars, copper prices suggest a recession

British Steel deal, ongoing Trade Wars, copper prices suggest a recession.. As stainless steel suppliers in the UK, we're keeping our finger on the British Steel pulse. Ongoing trade wars are putting aluminium prices under severe pressure. And the trend is supported...

Accreditations & Associations

Aluminium Stockholders Association

Quick Enquiry

  • South East
  • South West
  • London
  • South Wales
  • North Wales
  • West Midlands
  • East Midlands
  • North East
  • North West
  • Scotland
  • Northern Ireland