Inspectioneering

Graphitization

Explore this topic

Graphitization is a form of material degradation occurring when the microstructure of some carbon and low alloy steels breaks down after long exposure to elevated temperatures (825 - 1300 F), causing the metal to weaken and be susceptible to cracking failures. The steel tends to break down to form iron and carbon (graphite); the latter of which will migrate to the material’s grain boundaries forming graphite nodules, which are what causes the metal to become brittle, losing strength, toughness, creep resistance, and ductility.

Some of the more common failures associated with graphitization of components include brittle failures of welded carbon-molybdenum steel pipes and boundary components like high-energy piping and boiler tubes failing. Unfortunately, where it is a problem, graphitization is not something that you can do very much about aside from lowering operating temperatures or using different materials. Some processes however, require operating temperatures of 825 - 1300 °F and are best conducted using low alloy steels.

Material selection is the paramount for avoiding graphitization failures. Metallographic analysis of coupons cut from the walls of susceptible equipment is effective in determining if graphitization may be occurring.

Graphitization is a mechanism that engineers and inspectors need to be familiar with and know methods of detection and prevention.

Related Topics

Topic Tools

Share this Topic

Contribute to Definition

We welcome updates to this Integripedia definition from the Inspectioneering community. Click the link below to submit any recommended changes for Inspectioneering's team of editors to review.

Contribute to Definition
Articles about Graphitization
July/August 2003 Inspectioneering Journal

Graphitization is not something that operators can do much about, and thankfully it is not very common. We as engineers and inspectors have to know about this one and prevent it or detect it. It occurs when the microstructure of some carbon and...

Authors: John Reynolds
Partner Content

Auto-refrigeration can impose low temperatures onto process vessels and piping causing them to be at risk of brittle fracture, the sudden break-before leak phenomena that can result in catastrophic rupture of the equipment.

    Downloads & Resources related to Graphitization

      Inspectioneering Journal

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

      Company Directory

      Find relevant products, services, and technologies.

      Talent Solutions

      Discover job opportunities that match your skillset.

      Case Studies

      Learn from the experience of others in the industry.

      Integripedia

      Inspectioneering's index of mechanical integrity topics – built by you.

      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.

      Expert Interviews

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

      Event Calendar

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

      Downloads

      Downloadable eBooks, Asset Intelligence Reports, checklists, white papers, and more.

      Videos

      Watch educational and informative videos directly related to your profession.

      Acronyms

      Commonly used asset integrity management and inspection acronyms.