Evaluation of new designed reference blocks for calibration and NDT by optical and ultrasonic techniques

Abstract

Reference blocks are required for ultrasonic calibration and non-destructive testing (NDT). There are already in existence sets of reference blocks constructed according to American Society for Testing and Materials standards, but as the industry evolves, we need more reference blocks with varied designs. In this study, two reference blocks of steel and aluminum are constructed. These blocks have several sets of flat bottom holes (FBH) with different diameters (0.5, 1, 1.5, 2 and 2.5 mm), angles (45 • and 90 • ) and placements. The novel constructed reference blocks are evaluated using the ultrasonic and a displacement measuring interferometer (DMI). They allow for detailed FBH characterization in terms of defining their location, diameter, depth and so on. The two techniques show consistency in the majority of the outcomes. The expanded uncertainty of readings is found to be ±1.4 μm, according to DMI data. The findings show that the newly constructed blocks could be ideal for evaluating a variety of calibration factors including transducer sensitivity, dead zone, defect size, and depth. Furthermore, they can be used in NDT in various industries such as petroleum pipe production, steel manufacturing and so on.

Ultrasonic and Optical Investigation of Mercury Content Influence on Metrological Properties of Reference Alloy Materials

“…The results in Figure 14 indicate a decrease in the refractive index n values with increment of the mercury content of the alloy materials while the extinction coefficient k increased with increasing the percentage of mercury [34]. The refractive index of the material is inversely proportional with the longitudinal velocity [35]. So as shown in previous sections, the longitudinal velocity increased with increasing mercury content.…”

“…The surface roughness was determined using the ellipsometer analysis software and it is represented in Figure 15 [35]. The surface roughness is defined as a homogeneous layer of optical constants composed of a mixture (or combination?)…”

“…Due to adding mercury to the alloy materials, the chemical composition of the alloy material changed, and new bonds were created in the band gap between the valence and conduction bands. As the mercury density increased, the new bonds converted to molecular orbitals [35]. This yields a reduction in the gap in the interatomic structure of the alloy material, so the band gap of the mercury material will be narrower than that of pure alloy material.…”