| Industry: |
Oil & Gas |
| Specimen Description: |
Downhole motor rotor |
| Material: |
AISI 1040 |
| Environment: |
Corrosive drilling mud |
| Background: |
A hollow, fluted AISI 1040 carbon steel rotor in a downhole motor fractured while drilling a directional well. The chromium plated rotor was exposed to a corrosive, water-based drilling mud. |
| Time in Service: |
Unknown |
| Findings: |
Laboratory failure analysis findings showed that the rotor I.D. contained many cracks at a 45 o angle to the long axis of the rotor. Metallurgical examination of a typical cracked area showed that they were torsional fatigue cracks.Craze cracks in the chromium plating did not contribute to the cracking. |
