Metal Degradation in Components of a Refinery
The non-destructive analyses performed in a refinery revealed material degradation of the steel components. The opening of the equipment confirmed the diagnostic : blisters were visible on metal sheets and cracks were visible on welded parts.
Event Date
June 1, 2005
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Causes
Cause Comments
The steel degradation was caused by hydrogen attack.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
metal sheet, steel components.
Location Type
Location description
Industrial Area
Operational Condition
Pre-event Summary
The non-destructive controls performed were:1) AUBT =Advance Ultrasonic Backscattering Technique for metal sheet, 2) TOFD =Time Of Flight Diffraction for welded parts 3) magnetoscopy for steel parts containing 0,5% Mo, to detect high temperature hydrogen embrittlement.
Currency
Lessons Learned
Lessons Learned
The operator replaced urgently the corroded equipment with 1.25 Cr 4 steel shells.The resistance of 0.5% Mo steel to thermal etching by hydrogen was gradually questioned since the 1970s. It is currently considered to be similar to non alloyed carbon steel. Equipment in 0.5 % Mo steel operating under hydrogen must be identified and classified according to their criticality, inspected using the correct non-destructive techniques to identify hydrogen damage and be replaced systematically in the event of appearance of degradations especially in highly-sensitive equipment.
Event Nature
Emergency Action
Unknown
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
Event no. 33330 of the French database ARIA (accessed December 2020)