Corrosion-Resistant Steel: What’s the Best Recipe?

Filed in Mechanical Engineering by on July 2, 2016 0 Comments

The composition of steel isn’t one-size-fits all. There are dozens of variations of steel, all of which rely on a specific balance of iron, carbon, and one or more other elements for their distinctive properties. For every variety of steel there are unique purposes for which it is best suited across a range of industries.

In our latest Machine Design quiz, we asked: what element would you add to steel to make it corrosion resistant? To answer this burning question, let’s start by looking at the common elements used in steel alloys and how they change its properties:

 

nitrogenNitrogen promotes high yield and high tensile strength.

 

 

titanium

Titanium is great for high-heat resistance. For better weldability, reduce the percentage of titanium in the alloy.

 

 

sulfurSulfur creates excellent machineability.

 

Manganese adds hardness without brittleness, along with high tensile strength at low temperatures, making it ideal for use in cryogenics.

 

carbonCarbon is a basic building block of steel, but the proportions aren’t set in stone. The more carbon you have, the stronger the steel.

 

So far, great attributes for different kinds of steel to have, but nothing about corrosion resistance. Let’s keep going:

nickelNickel offers hardenability, along with corrosion resistance. (I think we’re onto something…)

 

Molybdenum is known for its resistance to specific kinds of corrosion, mostly from acids and molten materials.molybdenum

 

chromiumAnd Chromium’s main benefit is its overall corrosion resistance.

 

Now that we’ve narrowed it down, one question remains: which element makes for the best corrosion resistance in steel?

The answer? All three! The beauty of alloying elements is that you don’t have to choose just one. The best bet against corrosion is a combination of nickel, chromium, and molybdenum along with the standard iron and carbon.


To keep learning about the world of Machine Design and find out about our upcoming Mechanical Engineering graduate programs, visit our website.

As a mechanical engineer, how might you use corrosion resistant steel?  Comment below!

 

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