Objectives of nondestructive testing methods

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2. Objectives of nondestructive testing methods. Objectives Attributes Measured or Detected Discontinuities and Separations Surface anomalies roughness, scratches, gouges, crazing, pitting, imbedded foreign material Surface connected anomalies cracks, porosity, pinholes, laps, seams, folds, inclusions Internal anomalies cracks, separations, hot tears, cold shuts, shrinkage, voids, lack of fusion, pores, cavities, delaminations, disbonds, poor bonds, inclusions, segregations Structure Microstructure molecular structure; crystalline structure and/or strain; lattice structure; strain; dislocation; vacancy; deformation Matrix structure grain structure, size, orientation and phase; sinter and porosity; impregnation; filler and/or reinforcement distribution; anisotropy; heterogeneity; segregation Small structural anomalies leaks (lack of seal or through-holes), poor fit, poor contact, loose parts, loose particles, foreign objects Gross structural anomalies assembly errors; misalignment; poor spacing or ordering; deformation; malformation; missing parts Dimensions and Metrology Displacement; position linear measurement; separation; gap size; discontinuity size, depth, location and orientation Dimensional variations unevenness; nonuniformity; eccentricity; shape and contour; size and mass variations Thickness; density film, coating, layer, plating, wall and sheet thickness; density or thickness variations Physical and Mechanical Properties Electrical properties resistivity; conductivity; dielectric constant and dissipation factor Magnetic properties polarization; permeability; ferromagnetism; cohesive force, susceptibility Thermal properties conductivity; thermal time constant and thermoelectric potential; diffusivity; effusivity; specific heat Mechanical properties compressive, shear and tensile strength (and moduli); Poisson’s ratio; sonic velocity; hardness; temper and embrittlement Surface properties color, reflectivity, refraction index, emissivity Chemical Composition and Analysis Elemental analysis detection, identification, distribution and/or profile Impurity concentrations contamination, depletion, doping and diffusants Metallurgical content variation; alloy identification, verification and sorting Physiochemical state moisture content; degree of cure; ion concentrations and corrosion; reaction products Stress and Dynamic Response Stress, strain, fatigue heat treatment, annealing and cold work effects; stress and strain; fatigue damage and life (residual) Mechanical damage wear, spalling, erosion, friction effects Chemical damage corrosion, stress corrosion, phase transformation Other damage radiation damage and high frequency voltage breakdown Dynamic performance crack initiation, crack propagation, plastic deformation, creep, excessive motion, vibration, damping, timing of events, any anomalous behavior Signature Analysis Electromagnetic field potential; intensity; field distribution and pattern Thermal field isotherms, heat contours, temperatures, heat flow, temperature distribution, heat leaks, hot spots, contrast Acoustic signature
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  • Fall '19
  • The Land, Nondestructive testing, electromagnetic testing

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