Field metallographic replication (FMR) is a non-destructive sampling procedure used in the field to evaluate microstructures and other surface features when it is not possible or practical to cut specimens for laboratory analysis. The practices for FMR are described in ASTM E1351: Standard Practice for Production and Evaluation of Field Metallographic Replicas.
FMR allows Anamet’s trained engineers and technicians to effectively bring our metallography laboratory to a client’s site. Using portable polishing equipment, following modified metallographic-preparation procedures, we are able to prepare a metallography-grade polymeric replica film of a surface. Replica films are then viewed in the laboratory using either an optical or scanning electron microscope.
FMR provides our engineers with a two-dimensional view of the microstructure of a component, similar to that observed in an actual metallographic specimen cut from the component. Features such as grain size and deformation processing indications, carbides and internal cracks due to creep damage are easily identifiable in well-prepared replica films. FMR can confirm observations made by other non-destructive methods, such as acoustic emission tests, penetrant examination and ultrasonic flaw detection, and can go a step further by identifying the nature of the flaw, for example, whether a crack is intergranular corrosion or transgranular fatigue.
Under certain circumstances, the microstructure and metallurgical condition of a component can be evaluated on-site by one of Anamet’s materials engineers using a portable low-power field microscope following surface preparation, without the need for polymeric film replication, thereby saving laboratory film-evaluation time.
On-site use of FMR is a valuable, cost-effective, and time-saving tool in several circumstances, including during plant shut-downs, when down-time is not a viable option, when destructive cuts to equipment to remove specimens for laboratory evaluation is not advisable, or when it would be too costly to transport equipment to the laboratory for evaluation. FMR can also serve to document the metallurgical condition before and after the performance of repairs that may affect the microstructure, and hence the properties, of a material.
FMR can be a suitable and informative non-destructive procedure to use when making decisions about extended or continued service of a piece of equipment; to replicate fracture surfaces in the field (i.e., surfaces created when a part breaks), particularly when the fracture surface cannot be removed from its original location; or to further characterize surface flaws detected by other non-destructive techniques.
Anamet’s experienced and trained personnel are available to discuss effective uses of FMR at your location.