Metallography is performed to examine the constituents and physical structures of metals, most commonly using light optical microscopy. Typically, metallographic analysis involves a destructive process to extract a sample from a part, followed by sample preparation, which includes mounting, grinding, polishing and etching in order to reveal microstructural details. Once a sample has been prepared, it is ready to be viewed microscopically to perform an objective evaluation. Accu-Test Labs’ team of experienced metallurgists and trained metallurgical technicians incorporate advanced digital microscopy software in performing various types of metallographic evaluations, including:
Grain Size Determinations
Non-Metallic Inclusion Ratings
Volume Fraction Point Counts
Surface Treatment Assessments (Case Depths/Decarburization Depths/Coatings)
In Situ (Replica) Metallographic Evaluations
A metallographic examination performed using the naked eye, or with minimal magnification, is called a macroscopic examination. Using sample preparation techniques similar to those used in microstructure examinations, macrostructural details of a metal are revealed. Typically, a full cross-section of a part is examined. A cross-section is evaluated for the presence of various detrimental conditions, such as laps, cracks, seams, pores, surface conditions and centerline conditions. Grain flow is also commonly assessed in forged products. Macroscopic examinations assist in qualifying the overall condition of finished products. Accu-Test Labs performs macro examinations for qualifications of forgings, finished products, and welds.