An Asian petrochemical plant requested ETD to provide a quotation to perform testing, Root Cause Failure Analysis (RCA) and Life assessment Study, initially for two methanol reformer pigtail parts that have been removed from service. It was then proposed to examine a further four pigtail samples (two that have been removed from service, and two as-new samples).
The scope of the work included:
- Visual and dimensional examination of the (2 off) pigtail samples including internal and external appearance;
- Assessment of condition of the internal and external surface including identification of inclusions/ contaminations, welding defects etc (if any exists);
- Chemical analysis of weld material to determine the chemical composition of the pigtail weld filler material to establish actual material constituents and the level of aluminium & titanium;
- Metallographic examination of the pigtail samples using optical microscopy to assess the condition of internal and external surfaces, to identify phase changes in microstructure / material degradation/ precipitations and also to identify the damage mechanism(s);
- Hardness testing and evaluation to determine the equivalent tensile strength values (using published hardness/ UTS correlation tables) to assess the mechanical strength or softening of the pigtail materials or welds;
- Basic review of design drawings, design & operating parameters, previous failure and maintenance history.
- Detailing condition assessment and/or RCA based on the findings of above investigations to determine whether there are any damages/ cracks and the root cause(s) of the damage.
- Remaining life assessment of the pigtail components based on the findings of above detailed investigations.
- Examination of these specimens using Scanning Electron Microscope (SEM) to assess the presence and volume of gamma-prime phase and perform detailed analysis of microstructure.
- Performing Post Weld Heat Treatment (PWHT) on the welded joint of the pigtail samples;
- Comparing of the results, to determine the effect of in-service aging on the component.
- Compiling a report covering results of all above investigations, condition & life assessment, root cause analysis & recommendations for any further actions to be taken for safe operation of the pigtail components which are in service.
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