Steel Corrosion: Is Rust on Steel Myth or Reality?

steel corrosion

Stainless steel is unique from all other forms of metal. It is a steel alloy that contains at least 10.5% of chromium. The chromium makes stainless steel corrosion-resistant because the chromium reacts with surrounding oxygen to form a thin layer on top of the steel. Theoretically, this layer should prevent rusting.

 

Stainless steel is probably the most common type of steel used over a wide range of applications such as industrial equipment, building materials, tubing for electrical appliances, wires, bars, sheets, and even surgical equipment. This is because of the steel’s shiny lustre that adds to its aesthetic appeal. Its resistance to oxidation also makes it very low maintenance.

 

Among the four types of stainless steel - austenitic, ferritic, martensitic, and duplex - austenitic stainless steel is dominant in any industry, with over 70% of total stainless steel output. With 16% chromium mixed with carbon, it yields proper rust prevention. The other three types, while having lower chromium levels, still fares well in preventing localised corrosion in crevices and against stress corrosion cracking.

 

Will Stainless Steel Rust?

 

Based on the discussion above, the answer is yes, given certain extreme conditions. But compared to other industrial conventional steel, stainless steel has a higher resistance to rust. However, very long exposure to heat, moisture, grease, saline, and damaging chemicals will eventually corrode stainless steel.

 

What Steel Corrosion Can Ultimately Damage Stainless Steel?

 

General corrosion - The most common type of rusting and corrosion for any steel material. It is the uniform loss of metal over an entire surface due to rusting. This type of steel corrosion is also the most predictable and manageable. All four types of stainless steel are usually protected from general corrosion due to their chromium content. However, if the stainless steel is exposed to extreme corroding conditions, it may be a good idea to use products like the Unituff OGS (Seal'n 'Peel) to ensure rust and corrosion prevention.

 

Bimetallic corrosion - Rusting or corrosion that occurs due to an electrochemical process when one metal corrodes another because of the presence of electrolytes.

 

Intergranular corrosion - Occurs due to extreme heat exposure or when crystallites have collected at the steel edges. This is a common occurrence with austenitic stainless steel.

 

Pitting corrosion - Occurs when stainless steel is exposed to too many chlorides, resulting in localised corrosion that causes holes and cavities.

 

Crevice corrosion - May occur if two metals are joined together, or even if a metal is joined with a non-metal. Corrosion occurs between two joined surfaces.

 

Stress corrosion cracking - Corrosion occurs when a crack is formed due to tensile stresses coupled with corrosive environmental conditions.

 

In all the cases of the above types of corrosion, all these are preventable if the stainless steel surface is coated with a protective barrier specially made for stainless steel.

 

Consider the Unituff OGS for your rust prevention needs.