Radiographic method

It is advisable to have many reference radiographs indicating some common flaws for use by the technical personnel. Some ASTM reference radiographs are listed in Table 2.3. 

Some distinct features of flaws in castings and weldments are given below. 

Microshrinkage Dark feathery streaks or dark irregular patches corresponding to grain boundary shrinkage often encountered in Mg alloy castings 

Shrinkage porosity Gas porosity Appears as a localized honeycomb or mottled pattern due to improper pouring temperature or alloy composition (e.g., A1 alloys) Round or elongated smooth, dark spots located individually or in clusters distributed randomly in the casting due to release of gas during solidification or evaporation of moisture from volatiles from the mold surface 

Dispersed discontinuities Occur in A1 and Mg alloy castings. Appear as tiny voids scattered in parts or throughout the castings. Gas porosity and shrinkage porosity in A1 alloys are examples of this flaw 

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The determination of detonation velocity is based upon measurement of the time interval needed for the detonation wave to travel a known distance through the explosive under test. The methods used to determine VOD may be classified as mechanical methods (Dautriche method), electrical methods [pin oscillographic technique (POT)], optical methods and radiographic methods. The methods which are generally used for the determination of VOD are ... 

Traditional radiographic methods use two-dimensional film to record the attenuation of X-rays passing through a three-dimensional object. The... 

Cold shuts Inherent Ferrous and nonferrous cast material Liquid penetrant method Magnetic particle method for ferrous material Radiographic method... 

Convolution cracks Processing Nonferrous material Radiographic method... 

Inclusions Processing (weldments) Ferrous and nonferrous Radiographic method Eddy current method is used in thin-wall welded tubing coupled with reference standards... 

Morris and Morris [65] have introduced a radiographic method for determination of the specific surface area of a foam. 

Radiographic methods are used to make the diagnosis of an intraabdominal abscess. Plain radiographs may show air-fluid levels or a shift of normal intraabdominal contents by the abscess mass. G1 contrast smdies also may demonstrate this displacement of abdominal structures. Both these modahties provide indirect evidence of abscess presence but are not generally helpful in precisely locating the abscess. 

Brader et al. (2002) examined the accuracy of determining insect contamination in wheat by x-ray analysis. It was observed that the x-ray analysis technique is one of the most accurate methods next to ELISA in detecting late instar larvae of S. granarius in wheat. Hurlock (1963) compared the radiographic method with that of staining techniques, flotation method, and C02 analysis to detect hidden infestation of C. chinensis in dried whole green... 

Detailed thickness measnrements were carried out for all tubes in all four HRSGs using ultrasonic and radiographic methods. It revealed severe thinning/corrosion in economizer section, at tube inlets of each panel/header (approx. 0.8 mm per year). See Figure. 3 showing red circled locations. Metal loss was also noticed in other economser tubes at bends. Economizer junipers also revealed metal loss. No corrosion was noticed in evaporator or superheater tubes. 

Clinical Surveillance of UHMWPE Using Radiographic Methods... 

McCalden RW, Naudie DD, Yuan X, Bourne RB. Radiographic methods for the assessment of polyethylene wear after total hip arthroplasty. J Bone Joint Surg Am 2005 87(10) 2323-34. 

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