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Macroscopic Examination

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Macroscopic examination is an extension of the visual examination and evaluates quality and homogeneity of the part. It is used to determine the origin of the failure and the type of fracture such as ductile, brittle, torsion or fatigue. Microstructural features can be used to assess internal quality, presence of hydrogen flakes, chemical segregation, hard cases, flow lines, and welds. A stereomicroscope (1–50×) is often utilized for the macroscopic examination. It is during this step that the fracture surface is evaluated. The first piece of information often observed is where the fracture initiated, that is, locating the fracture “origin” or “origins” and determining whether it/they are located at the surface or below the surface. It is also important to note the fracture direction in relation to the normal or expected loading. Markings on the fracture surface formed during the initiation and propagation of the crack can be used to evaluate the fracture and determine origin of cracking. Examination of the origin by the experienced failure analyst may reveal the cause and determine any contributing factors toward failure.

Root Cause Failure Analysis

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