Metal Corrosion

 

Through a phenomenon known as corrosion, nature can wear away the materials that make up various structures and components. From pipelines and valves to fuel tanks and bridges, these structures can weaken or deteriorate altogether, causing safety hazards and financial losses to both public and private entities.

Corrosion can also threaten our health by releasing toxic substances into our air and water supplies, making this natural yet dangerous process so much bigger than an economic concern.

According to the American Galvanizers Association, around 85 percent of all steel manufactured is carbon steel. This means the majority of steel is prone to oxidation and erosion. Identifying the different types of corrosion is essential for preserving and maintaining structures, as well as for protecting the public’s health and safety.

Causes and Types of Corrosion

Here are the most common types of metal degradation and their causes:

1. Uniform Corrosion

The most prevalent form of corrosion, uniform corrosion, is a type of attack that strips away the entire surface layer of a metal structure. Exposure to strong acids and hot alkaline environments are the usual causes. Unaddressed, the metal will continue corroding and eventually fail.

2. Galvanic Corrosion

Galvanic corrosion occurs when two dissimilar metals come into contact in an environment with electrolytes. Electrolyte-heavy air can push galvanic corrosion into hyperdrive, causing the metal to corrode ten times quicker compared to air with normal salt or moisture levels.

3. Pitting Corrosion

Pitting corrosion affects specific locations on a metal surface. It results in deep depressions or holes that can weaken the metal over time. This corrosive attack arises due to the presence of chloride ions and other contaminants in the surrounding environment.

4. Crevice Corrosion

This common form of metal corrosion occurs when an electrolyte seeps into crevices or cavities in a metal structure.

5. Stress Corrosion Cracking (SCC)

Stress corrosion is a rare circumstance whereby metal components become subject to both tensile stress and corrosive environments simultaneously, leading to unexpected and immediate failure. SCC emerges when metals or alloys react with an aggressive environment at elevated temperatures, causing the material to crack without warning.

6. Selective Corrosion

Metal is susceptible to a variety of corrosion-related problems, the worst being selective attacks like dezincification, dealuminification, or intergranular corrosion.

7. Cavitation Corrosion

This physical process occurs when gas bubbles form in the liquid, creating an environment where localized erosion can transpire. The energy from these shear forces can erode metals quickly.

8. Erosion Corrosion

One of the most common types of corrosive attacks, erosion corrosion wears down metals and alloys due to the continuous abrasion between relative metal surfaces in corrosive fluids. This insidious process can leave damaging surface grooves, indentations, and other irregularities.

9. Flow-Assisted Corrosion

Flow-assisted corrosion results from the combination of chemical and mechanical processes that arise when water or other corrosive liquid flows over a metal surface. This corrosive attack is extremely damaging, as it can remove protective oxide coatings on a metal surface and cause deep pitting, cavitation, and erosion.

How to Prevent Corrosion Before It’s Too Late

Let Industrial Inspection Group, Inc. provide the solution to corrosion you need. We know that industrial projects can be complex and involve many different components, which is why our QP5 coatings inspectors take great care to ensure accuracy and quality throughout the process. Our team uses state-of-the-art equipment to measure conditions, detect flaws, and assess coatings before moving on to the specification development and coating application processes. We also have stringent safety protocols to guarantee the safety of all personnel on-site.

For more information on how we can meet your specific industrial coating needs, contact us at 480-637-5238.