Is Stainless Steel Corrosion Resistant?

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Corrosion resistance is a great property of stainless steel. When exposed to high pressure and temperature, the surface remains free of deposit. Do you know the basic point of Carbon steel vs. stainless? Stainless steel has corrosion resistance properties and is used in several environments whereas carbon steel will rust. Although it suffers from different types of corrosion, the rate can be slower, which means that stainless steel provides better uptime than carbon steel.

Stainless steel is does not corrode easily

Corrosion resistance is due to thin layer formed on the steel’s surface. This oxide layer is known as the passive layer, which means the steel’s surface is electrochemically passive due to the presence of a corrosive environment. A passive layer is formed when chromium is added to SS. Stainless steel must have 10.5% chromium to form this passive layer. The passive layer will become more stable if more chromium is added to improve the corrosion-resistant property. Other elements are added to stainless steel to increase its corrosion-resistant nature, such as manganese, molybdenum, nickel, etc. The next requirement for maintaining the passive layer is that the steel surface should be exposed to oxygen. When steel is exposed, corrosion resistance will be greater, and the surface can remain free of deposit.

Types of corrosion

The main alloying element which makes stainless steel highly resistant to the corrosive environment is chromium which forms a thin protective layer around the surface of the metal and protects it from the outside environment. As a result, all stainless steel is highly resistant; however, it is not immune to other types of corrosion.

Intergranular corrosion

The corrosion resistance can be degraded when fabrication of the structures and components of stainless steel. This can occur when 304-grade austenitic stainless steel has greater exposure to high temperatures between 797°F to 1598°F.

What affects the corrosion resistance nature of stainless steel?

The chromium interacts with the oxygen in the atmosphere and forms a secured layer which helps make stainless steel highly resistant to rust and corrosion. There are more than 150 grades of stainless steel available in the market because it is resistant to staining and oxidation and has low maintenance features. Some grades of seamless steel are low resistance to rust and corrosion compared to others, as the chromium content differs in different steel grades. The high chromium content and density of stainless steel make the stainless steel metal prone to rust and corrosion. Over time, if this is not maintained properly, it can also become corroded. The factors which affect the corrosion of stainless steel are as follows.

What are the different types of corrosion of stainless steel?

1. General corrosion
2. Galvanic corrosion
3. Pitting corrosion
4. Crevice corrosion

The corrosion-resistant nature of stainless steel depends on the elements in different grades. The environment in which stainless steel is exposed is also a major factor that affects corrosion. For example, environments with chlorine are highly corrosive such as swimming pools. There are other environments where salty water can increase rate of corrosion. Maintenance also creates an effect on the stainless steel material.

Chromium in stainless steel interacts with oxygen and forms a chromium oxide layer on the surface of the metal. This protective oxide layer is thin and protects this metal from corrosion. The protective oxide layer can be destroyed in a harsh environment or due to mechanical damage like scratches. However, if proper maintenance and a suitable environment are maintained, stainless steel’s protective properties will be restored. Shalco Industries offers a wide range of stainless steel grades per the industries’ requirements.
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