Inspectioneering

Corrosion and Materials is a field of study that focuses on understanding the causes and mechanisms of corrosion. According to API 510 and API 570, corrosion and materials specialists are professionals who are “knowledgeable and experienced in the specific process chemistries, degradations mechanisms, materials selection, corrosion mitigation methods, corrosion monitoring techniques, and their impact on equipment and piping systems.”

In reality, the roles and responsibilities of corrosion and materials engineers are extensive. Not only are they relied upon for corrosion and material expertise, they also have to be knowledgeable about nondestructive examination methods, inspection planning, risk-based inspection, process safety management, and much more. A list of 50 important roles and responsibilities of a corrosion and materials specialist can be found here.

Corrosion

Corrosion is one of the most problematic issues in the oil and gas and process industries and often leads to significant operation and maintenance costs. Corrosion takes place in a variety of environments from atmospheric conditions to aqueous solutions. The primary corrosive agent is dissolved oxygen, followed by sulfur compounds and salts, such as sodium chloride (which is inevitably found in marine environments).

Corrosion can develop in a number of different forms. The specific form is dependent on the environment in which a piece of metallic equipment is operating. The most common types of corrosion include:

Each of these processes occur by a specific mechanism and are dependent on the type of material, design of the component, and environmental conditions.

Corrosion also occurs at various rates and is determined by evaluating the amount of material loss over time. The rate of corrosion is also associated with the chemical reaction between the metal component and the surrounding environment. The basis of this chemical reaction is the transfer of electrons. Unfortunately, this reaction occurs spontaneously and is also electrochemically favourable, making corrosion issues difficult to manage.

Materials

Corrosion can have negative effects on ceramics at high temperatures, however, the most severe effects occur with ferrous metals. Metals should be carefully selected in order to optimize facility production and eliminate premature failure. Furthermore, metal materials should inherently possess corrosion and high-temperature resistance properties as well as desirable mechanical properties. The material selection process should also take into account material availability, costs, and safety. Once a material is selected, the design and fabrication of an asset should meet specifications and align with the facility’s goals to perform a specific function.

For example, stainless steel, galvanized steel, plain carbon steel, and aluminum and copper alloys are metals used in atmospheric environments. In marine environments, titanium, brass, and copper-nickel alloys are some of the materials of choice used in offshore oil facilities.1 If small amounts of corrosion are identified, the component may be repairable. However, significant corrosion damage can alter the ductility or strength of a component which can lead to adverse consequences.   

Corrosion Control

Each type of corrosion can be treated individually using a number of methods. However, there are several general corrosion prevention techniques that can help control corrosion. These techniques include proper material selection and equipment design, protective coatings and films, the addition of corrosion inhibitors, and cathodic protection. Nondestructive testing techniques are also effective methods for monitoring corrosion and providing information of the condition of a component.

References

Callister Jr., W.D., Rethwisch, D.G. Materials Science and Engineering. 9th ed., John Wiley & Sons, 2014.

STAY INFORMED WITH RELEVANT INDUSTRY CONTENT

Join 10,000+ subscribers and receive weekly updates on industry content, news, and events straight to your inbox. Enter your information below:

Articles
    Videos
      White Papers
        Downloads & Resources
          Events
            Related News

              Inspectioneering Journal

              Explore over 20 years of articles written by our team of subject matter experts.

              Company Directory

              Find relevant products, services, and technologies.

              Job Postings

              Discover job opportunities that match your skillset.

              Case Studies

              Learn from the experience of others in the industry.

              Event Calendar

              Find upcoming conferences, training sessions, online events, and more.

              Industry News

              Stay up-to-date with the latest inspection and asset integrity management news.

              Blog

              Read short articles and insights authored by industry experts.

              Asset Intelligence Reports

              Download brief primers on various asset integrity management topics.

              Videos

              Watch educational and informative videos directly related to your profession.

              Expert Interviews

              Inspectioneering's archive of interviews with industry subject matter experts.