Technical Department

14 January, 2021
Stainless steel and its properties

Strong, resistant, with great tolerance to pressure and extreme temperatures, stainless steel is the main metal used for industrial processes. And there is even more, the alloy that makes up stainless steel makes it resistant to corrosion, it is a material that can be cleaned and its malleability allows the creation of devices such as industrial valves in a large number of sizes and shapes. But what makes it so special? Let’s look at its composition first.

Stainless steel and its properties

What is stainless steel?

Stainless steel is a group of iron-based alloys that contain a minimum of chromium (approximately 11%), a composition that prevents iron from rusting and also provides heat-resistant properties.

The resistance of stainless steel to oxidation results from the presence of chromium in the alloy, which forms a passive film that protects the underlying material from corrosion attack and can regenerate in the presence of oxygen.

Corrosion resistance will increase if the chromium content is increased to levels above 11%; and with the addition of 8% or more nickel; and the addition of molybdenum (which also improves resistance to “pitting corrosion”).

But not all stainless steel is made equal! There are thousands of grades of stainless steel, the most common being 304 and 316. Those numbers represent the chemical composition of the material, which is at least 50% iron and 13% chromium.

Stainless steel and its properties

Why is stainless steel so amazing?

The popularity of stainless steel is no mere coincidence, compared to its siblings, stainless steel is stronger than cast iron, ductile iron, brass, and copper.

Although it competes with carbon steel in many respects, stainless steel is far superior in corrosion resistance. For this reason, we find stainless steel valves in areas where materials with remarkable resistance to pressure, high temperature and corrosion are required.

Despite being practically unbeatable by other metals, stainless steel has one point against it: its price. It is clear that there is a large price difference between iron and stainless steel, but that translates into an improvement in quality and properties that are usually required by certain applications and that, in addition, over time, stainless steel valves will pay for themselves. that investment of extra cost thanks to its greater resistance to wear that this magnificent material confers on them.

Where do we find stainless steel valves?

Thanks to its excellent qualities, the use of stainless steel valves has spread practically in all sectors of the industry, but the following would be within industrial applications where its use is indispensable.

Chemical and petrochemical industry

Not surprisingly, stainless steel valves are welcomed in the chemical and petrochemical industry, the presence of chromium in stainless steel alloy versus carbon steel prevents corrosion from penetrating the metal. Another of its advantages over carbon is that stainless steel is 100% recyclable.

In petrochemical applications there are several highly demanding processes: such as cryogenic, high temperatures, high pressure, corrosive environments or processes that require materials of maximum purity.

Seawater environments

Some processes are carried out near sea water such as desalination. Marine environments are corrosive and harmful to all kinds of materials that are involved in the process. For this, plastic is usually used for its anticorrosive properties superior to metals, however, its ability to resist high pressures and temperatures places stainless steel back in the frame, being bronze valves (read article) , the only ones that would be above performance for this type of application.

Brewing industry

Valves, normally located on the kettle, are required in brewing processes to allow control of fluid transfers by operators. The beer or whiskey brewing process generates wort, a highly corrosive substance that will wear away the iron valves. Since plastic valves cannot operate at the high temperatures present in brewing, stainless steel is once again the best option.

In conclusion, stainless steel valves have characteristics that make them a favorite for most applications. Next, we invite you to discover our range of valves and industrial instrumentation in stainless steel.