Table of contents

Preface

Organizing conference on a very specialize field in this country is really challenging effort. This fact is also true when organizing the 'Malaysia International NDT Conference and Exhibition 2018 (MINDTCE'18) on 12 and 13 November 2018. Persuading national and international members of NDT experts to participate and to share their knowledge and experience in such a conference is considered as the biggest challenge that has to be overcome by members of organizing committee. For this reason, when the event was successfully held with an excellent response from the presenters, exhibitors and normal participants, every individual involved on the organization of this event were so relieve and delighted. Thanks and congratulation to all especially members of Steering Committee who has spent days and nights making efforts to ensure that the event executed in the best possible manner.

Members of Organizing Committees thanks all presenters who has agreed to have their papers that contain extremely valuable information and data that took years for them to collect and produce. In order to enhance their quality, these papers were edited by a number of national and international experts. The organizers thanks the publisher, IOP Publishing who values these papers qualified to be published in Scopus indexed journals of Material Science and Engineering. We hope this publication add to one more source of rarely published knowledge in the field of NDT that are needed by researchers and practitioners throughout the world in their strive to enhance the role of NDT in creating safer and cleaner work environment for all mankind.

All papers published in this volume of IOP Conference Series: Materials Science and Engineering have been peer reviewed through processes administered by the proceedings Editors. Reviews were conducted by expert referees to the professional and scientific standards expected of a proceedings journal published by IOP Publishing.

Pulsed eddy current (PEC) is an advance Non-destructive testing that is widely used in multiple industries for surface and subsurface defect detection. Normally, the conventional features extractions are conducted based on time to peak and peak value response. However, signals extraction could be a confusing for a thin specimen because times to peak for both surface and subsurface defects are occurred at almost similar time. This paper introduced the application of confirmatory Factor Analysis for defect categorizing for stainless steel thin plate. Through this statistical method, two categories of defects namely surface and subsurface defects are clearly to be distinguished between one to another.

This paper explained the procedure to carry out the ultrasonic inspection for single and double-V butt welded plates in detail by including the calculation of skip distance, stand-off, interpretation from plotting system, and the preparation of full inspection report as well. In addition, few inspections were compared on butt welded plate single and double-V to determine which is the most suitable, accurate and precise reading obtained. The comparisons were made between scheme answer from Sirim inspector, X-ray film, data that obtained from ultrasonic inspection and calculation by mathematical formulas and using plotting system. Mathematical formulas and plotting system was utilized to obtained the distance of stand-off (S_off) and skip distance, (S_max) whereas the plotting system were applied to locate the defects based on their S max and S off, and also to determine the depth, d and radius, r. The defects of single-V and double-V butt welding inspected by the ultrasonic technique were then compared with those obtained from the radiographic film while a good agreement was observed. However, the ultrasonic inspection proved to be much more sensitive than the radiographic inspection.

Planar conductors are commonly used in critical mechanical structures. Due to high-temperature and high-pressure environment, corrosion may occur in in-service planar conductors, and seriously threatens structural integrity and safety. Hence, it is indispensable to detect and evaluate corrosion using Non-destructive Testing (NDT) techniques before structural failure. As a technique complementary to other Electromagnetic NDT methods, Microwave NDT is found to be advantageous in terms of high efficiency and accuracy in inspection of conductors subject to surface flaws. In this paper, a millimetre-wave probe for efficient detection and evaluation of corrosion in planar conductors is proposed and intensively investigated via simulation. A 3D Finite Element (FE) model of the proposed probe is established based on electromagnetic wave theory. The characteristics of the microwave propagation along with the mechanism regarding corrosion detection are intensively analysed. The probe structure and parameters are subsequently optimised in an effort to enhance the detectability, sensitivity and accuracy in corrosion evaluation. Besides, signal processing techniques involving extraction of features from the S-parameter in the function of frequency are investigated.

This paper describes the remaining wall thickness assessment using Ultrasonic Testing Phased Array (UTPA) technique. A steel plate of thickness 15 mm consists of machined simulated corrosion with various thicknesses, depths, shapes, and sizes were used in this work. Manual corrosion scanner is attached with GE Phased Array (PA) thirty-two elements (transmitter and receiver) Dual Matrix probe of 5 MHz with 1.5 mm pitch is used. The scanner then applied firmly on the plate to execute the inspection. From the result, the relevant indications from the A, B and C-Scans display are collected and analysed. The outcome of the study revealed that UTPA technique is capable to collect a high density of measuring point of thickness compared to the conventional UT technique such as Ultrasonic Testing Thickness Gauge (UTTG).

Radioactive particle tracking (RPT) is one of the non-invasive techniques for monitoring and investigating multiphase flow system. This technique have been widely utilized in the field of chemical process engineering for better understanding and optimizing process hydrodynamics especially in the multiphase reactor such as bubble column reactor. Due to opaque nature of industrial process systems, especially in the case of multiphase flows, noninvasive methods based on ionizing radiation have been considered for evaluating the hydrodynamic parameters. The feasibility study of radioactive particle tracking techniques in quadrilateral bubble column reactor has been successfully achieved. The radioactive particle tracking facility and data acquisition system has been developed and experimental calibration using single particle radioactive particle ⁴⁶Sc to investigate dynamics behaviour of quadrilateral bubble column reactor is completed. The results indicated that there is back mixing behaviour in the bubble column process. The results also reported that the radioactive particle ⁴⁶Sc is still in good condition and there is no radiation contamination problem arises while performing radioactive particle tracking techniques. The RPT technique was performed to reveal the instantaneous velocity and time-averaged liquid velocity in the current bubble column reactor.

The role of metallic screens in computed radiography for controlling scattered radiation is very well-known. Likewise, the intensification effects of certain lead screen thicknesses with higher X-ray energies, such as those produced by gamma isotopes is also a topic that has been recently investigated in literature. This paper extends this topic further and quantitatively investigates how image quality in terms of signal-to-noise ratio (SNR) and basic spatial resolution (SR_b) is influenced by metallic screens when Iridium-192 is used as the radiation source. The result data is then used to make recommendations to achieve optimum image quality when using Iridium-192.

Laminography is a technique used to determine the depth of a defect in Radiographic Testing (RT). It enables RT operators to accurately locate the defect from the object's surface especially for welded components. The technique will ensure the quality of weld components meets the standard requirement for reliability and safety purposes. This paper intends to study the exposure parameters of laminography technique on carbon steel plate by using Radiographic Testing – Digital. (RT-D). The important exposure parameters that are considered in this preliminary study are voltage, current, and frame time. The radiography images with achievable level of contrast sensitivity and image quality are analyzed according to the ISO 17636-2. Discussion on correlation between the normalized Signal to Noise ratio (SNR_N) and the exposure parameters are done based on the plotting graphs. The results show the exposure parameters has significantly influenced the value of SNR_N. Further experimental works are performed using triangulation technique on welded sample. The deviation between the calculated depth of defects and actual results is less than 1.0mm.

The application of the radiographic simulation studies on the weld joints in nuclear fuel reprocessing tanks used for optimization of radiographic testing parameters. In the nuclear reprocessing plant, Annular and cylindrical tanks are used to store the reprocessed solution of the spent fuel pins from the reactor. These annular and cylindrical tanks were installed 15 years ago. AERB (Atomic Energy Regulatory Board) has requested for requalification of these tanks before commissioning. As part of the requalification of tanks, the volumetric NDE techniques were proposed to be used for evaluation of the weld joints in the tanks. Before carrying out the radiographic examination on the actual tanks, computer simulation of radiography was studied on standard weld pad. Radiographic simulation is utilized for various purposes in NDT. This radiographic diagnostic model utilized for study about incorporates a description of the radiation source, the interaction of radiation with test pieces and defects, and the detection process. The modeling results were validated with radiographic inspection carried out with weld pad sample of 6mm thickness. The error percentage in the optical density achieved between simulation and experiment radiographic inspection was ± 5%. Hence the optimization parameters using simulation for the weld pad helps to reduce the number of exposures, inspection time and increase defect detectability of the inspection.

The A320 aft fixed fairing is an advanced composite structure fabricated from laminate carbon woven and combines with honeycomb core which is externally mounted on the flap track fairing as a wing part of Airbus aircraft. These flaps are movable control surfaces to widen up the surface of the wing in order to increase the lifting. This paper discussed on the inspection of A320 aft fixed fairing by using shearography NDT technique. Shearography technique reveals the stress-affected zone due to additional loading that can be realized by the laser speckle correlation on the inspected composite panel. This A320 aft fixed fairing is identified as a scrap composite panel which having different sizes and orientations of defect. The results showed that the changes of shearing direction in laser shearography technique are an effective means to reveal the defects propagation in the composite component. The shearing at Y-axes direction is able to detect the cracks at horizontal orientation while shearing at X-axis has successfully detects the cracks at vertical orientation. Therefore, shearography could be utilized as an alternative inspection for other NDT method for inspection of composite material.

Aluminum filler (Al-5%Si) is bonded on steel substrate by gas tungsten arc welding process under different current setting conditions. After welding a thorough metallographic analyses using optical and scanning electron microscopy were carried out to observe Al-Steel interface. Ultrasonic measurements by immersion and scanning acoustic microscopy were made to characterise the bond at Al-Steel interface. The ultrasonic wave reflected from the Al-Steel interface clearly indicated the more debonded area when the welding current is changed from direct current straight polarity (DCSP) mode to alternate current high frequency (ACHF) or the welding current in case of current for DCSP mode is reduced. This may be attributed either adequate amount of oxides along with intermediate phase make the bond interface rough and uneven due to introduction of ACHF mode or debonded areas are higher due to lower heat input when the current reduced to 125 amps from 150 amps in DCSP mode. Whereas smooth and even bond interface due to uniform heat input resulted stable Al-Steel interface and the mapping of bonded area by ultrasonic measurement showed spectrum of minimum peak for using current of 150 amps in DC mode. Thus the non-destructive assessments of interface between dissimilar materials through ultrasonic measurements could be important tools for evaluating the state of the bond.