and C. However, parts will not fit well together because of plastic deformation that occurred before or during the fracture process. B Fig. 2 Fractured lug, part of a pin-joint assembly, showing sequence of fracture Fracture a preceded fractures B and c Preliminary Examination The failed part, including all its fragments, should be subjected to a thorough visual examination before any cleaning is undertaken. Often, soils and debris found on the part provide useful evidence in establishing the cause of failure or in determining a sequence of events leading to the failure. For example, traces of paint or corrosion found on a portion of a fracture surface may provide evidence that the crack was present in the surface for some time before complete fracture occurred. Such evidence should be recorded photographical Visual Inspection. The preliminary examination should begin with unaided visual inspection. The unaided eye has exceptional depth of focus, the ability to examine large areas rapidly and to detect changes of color and texture. Some of these advantages are lost when any optical or electron-optical device is used. Particular attention should be given to the urfaces of fractures and to the paths of cracks. The significance of any indications of abnormal conditions or abuse in service should be observed and assessed, and a general assessment of the basic design and workmanship of the part should also be made. Each important feature, including dimensions, should be recorded, either in writing or by sketches or photographs It cannot be emphasized too strongly that the examination should be performed as carefully as possible, because clues to the cause of breakdown often are present, but may be missed if the observer is not vigilant. Inspection of the topographic features of the failed component should start with an unaided visual examination and proceed to higher and higher magnification. A magnifying glass followed by a low-power microscope is an invaluable aid in detection of small details Examination and Photography of the Damaged/Failed Part or Sample. The next step should be preliminary examination and general photography of the entire part and damaged or failed regions. Where fractures are involved, the entire fractured part, including broken pieces, should be examined and photographed to record their size and condition and to show how the fracture is related to the components. This should be followed by careful examination of the fracture. The examination should begin with the use of direct lighting and proceed at various angles of oblique lighting to delineate and emphasize fracture characteristics. This should also assist in determining which areas of the fracture are of prime interest and which magnifications will be possible(for a given picture size) to bring out fine details. When this evaluation has been completed, it is appropriate to proceed with photography of the fracture, recording what each photograph shows, its magnification, and how it relates to the other photographs. For information on photographic equipment, materials, and techniques, see the article Photography in Failure Analysis" in this Volume and the article entitled" Photography of Fractured Parts and Fracture Surfaces, on pages 78 to 90 in Fractography, Volume 12 of the Metals Handbook, 9th edition(now Volume 12 of the ASM Handbook) Nondestructive Inspectionand C. However, parts will not fit well together because of plastic deformation that occurred before or during the fracture process. Fig. 2 Fractured lug, part of a pin-joint assembly, showing sequence of fracture. Fracture A preceded fractures B and C. Preliminary Examination The failed part, including all its fragments, should be subjected to a thorough visual examination before any cleaning is undertaken. Often, soils and debris found on the part provide useful evidence in establishing the cause of failure or in determining a sequence of events leading to the failure. For example, traces of paint or corrosion found on a portion of a fracture surface may provide evidence that the crack was present in the surface for some time before complete fracture occurred. Such evidence should be recorded photographically. Visual Inspection. The preliminary examination should begin with unaided visual inspection. The unaided eye has exceptional depth of focus, the ability to examine large areas rapidly and to detect changes of color and texture. Some of these advantages are lost when any optical or electron-optical device is used. Particular attention should be given to the surfaces of fractures and to the paths of cracks. The significance of any indications of abnormal conditions or abuse in service should be observed and assessed, and a general assessment of the basic design and workmanship of the part should also be made. Each important feature, including dimensions, should be recorded, either in writing or by sketches or photographs. It cannot be emphasized too strongly that the examination should be performed as carefully as possible, because clues to the cause of breakdown often are present, but may be missed if the observer is not vigilant. Inspection of the topographic features of the failed component should start with an unaided visual examination and proceed to higher and higher magnification. A magnifying glass followed by a low-power microscope is an invaluable aid in detection of small details of the failed part. Examination and Photography of the Damaged/Failed Part or Sample. The next step should be preliminary examination and general photography of the entire part and damaged or failed regions. Where fractures are involved, the entire fractured part, including broken pieces, should be examined and photographed to record their size and condition and to show how the fracture is related to the components. This should be followed by careful examination of the fracture. The examination should begin with the use of direct lighting and proceed at various angles of oblique lighting to delineate and emphasize fracture characteristics. This should also assist in determining which areas of the fracture are of prime interest and which magnifications will be possible (for a given picture size) to bring out fine details. When this evaluation has been completed, it is appropriate to proceed with photography of the fracture, recording what each photograph shows, its magnification, and how it relates to the other photographs. For information on photographic equipment, materials, and techniques, see the article “Photography in Failure Analysis” in this Volume and the article entitled “Photography of Fractured Parts and Fracture Surfaces,” on pages 78 to 90 in Fractography, Volume 12 of the Metals Handbook, 9th edition (now Volume 12 of the ASM Handbook). Nondestructive Inspection