Metallographic Techniques in Failure Analysis

Important clues about the probable cause of a gun tube explosion were obtained from a fractographic and metallographic examination of the fragments. The size, distribution, and surface markings of fragments may be used to localize the explosion and deduce its intensity. Microstructural features such as voids, adiabatic shear, and structural surface alterations also indicate the explosion intensity and further allow a comparison of the tube structure near and away from the explosion zone. These, and other metallurgical characteristics, are illustrated and discussed for cases of accidental and deliberately caused explosions of large caliber gun tubes.

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Field Metallography Aids NDT of Evaluation of Indications in Turbine Main Column Horizontal Plate Welds at Power Plant

Diaz¹,

Benson²

2019

ASM Failure Analysis Case Histories: Power Generating Equipment

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An evaluation of indications in the main turbine building column horizontal plate welds was conducted by the joint efforts of field metallography and nondestructive examinations. The turbine building main column horizontal plate welds were selected at random and were inspected to find discontinuities, metallurgical evaluation of the discontinuities, analysis of any failure modes, and determination of the best repair techniques. The welds were made with prequalified joints in accordance with AWS D1.1-77 and required only visual inspection. More sensitive inspection methods were applied to the welds in order to better define the indications found with the visual inspections. Cracks were found in 17 field welds and in two test plate welds. The causes of the cracking are related to the weld design and installation procedure. Three field welds were rejected because of the depth of the cracks. The NDT inspections, evaluations, method of field metallography, analysis and conclusions are discussed with recommendations for corrective actions in the following report.

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Metallographic Techniques in Failure Analysis

Cited by 10 publications

References 15 publications

Failure analysis of a high-speed pinion shaft

Failure analysis of a high-speed pinion shaft

The Role of Metallography and Fractography in the Analysis of Gun Tube Failures

Field Metallography Aids NDT of Evaluation of Indications in Turbine Main Column Horizontal Plate Welds at Power Plant

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