Macro Inspection Research Articles

40‐4: Improving Visibility Coherence between Auto Macro Inspection and Auto Visual Inspection Using AI Image Translation

In OLED production, the glass fabrication process is prone to frequent occurrences of persistent mura defects, leading to significant damage in the event of defects, as the subsequent final inspection, AVI (Auto Visual Inspection), is time‐consuming. Therefore, there is a need for a consistent inspection. Currently, manual inspection by operators introduces variations in inspection criteria among individuals, resulting in ongoing challenges related to false judgments and post‐process leakage issues The invested automated inspection system for quantitative determination is utilized as a reference only, as the distinction between pseudo‐defects deemed acceptable in AVI and true defects identified as faulty in AVI poses limitations with the traditional logic‐based inspection methods. We enhanced the mura visibility of automatic inspection system (Auto Macro) images through pre‐processing, followed by translation into an image environment similar to AVI images using Pix2pix GAN. Subsequently, we compared the mura index extracted from the processed images with the AVI mura index for evaluation. The Auto Macro images transformed by Pix2pix GAN exhibited similarities with AVI images in terms of overall luminance, gray distribution, and mura visibility intensity. Consequently, the R‐Squared correlation between the mura index of Auto Macro and AVI improved from 0.00 to 0.68. Additionally, defects unrecognized in AVI during Auto Macro inspection were automatically eliminated. False defects in the Auto Macro test that were not recognized in AVI were automatically removed. In this study, we applied the AI model to the Auto Macro inspection system to overcome the limitations of logic‐based inspections. We proposed a method to proactively detect defect‐induced muras before cell‐level processing, aiming to improve yield and reduce incidents of customer leakage accidents.

Failure analysis of 2205 duplex stainless steel connecting pipe for composite plate pressure vessel in a high pressure gas field

Pitting and cracking failure of 2205 duplex stainless steel connecting pipe in a high-pressure gas field occurred. Macro inspection, non-destructive testing, physical and chemical tests, corrosion tests and heat treatment were carried out for the pipe in order to identify the failure cause and mechanism. The results showed that large-size non-metallic inclusions composed of MnS and (Si, Mn, Ca, Al, Cr, Mg) oxides and existence of tiny precipitates didn't meet the requirements of Order Technical Agreement, which resulted in a serious reduction in the impact toughness and pitting resistance. The main reason for the failure is the existence of the harmful precipitates produced by stress relief annealing and large-size non-metallic inclusions. The rapid deterioration of the corrosion environment in the past three years has played a role in inducing and promoting the failure. Fine precipitates mainly reduce the impact toughness, while large-size non-metallic inclusions mainly reduce the pitting resistance. The formation of pits and the large-size non-metallic inclusions are the key factors for the generation of micro cracks, and the fine precipitates accelerate the crack growth.

Failure Analysis of Oil Pipe Fracture in Steam Turbine Oil Supply System of Power Plant

Oil pipe fracture of the steam turbine oil supply system of a thermal power plant is carried out by macro inspection, spectral analysis, metallographic analysis, hardness analysis, and scanning electron microscope analysis. The results show that the fractured tubing is a fatigue fracture, and the source of the crack is the fatigue crack formed by the stress concentration of the weld, which eventually leads to the fracture and leakage at the place.

Analysis of 330 kV B busbar tripping accident in a 330 kV substation

In this paper, the damage to the bus conductor and expansion joint caused by the tripping accident of bus B of a 330 kV line in Northwest China was taken as an example, and the reasons for the tripping accident were analyzed and improvement measures were proposed utilizing macro inspection and cross-cut test. The results showed that the main reason for this failure is that the manufacturer did not strictly implement the coating process, resulting in insufficient coating adhesion, and the coating gradually cracked and fell off during operation. The peeling coating caused air gap breakdown and ground flashover.

Failure Analysis of the Metal Hose Puncture and Leakage in a Natural Gas Reinjection Station

The metal hose in the pump room of an oilfield natural gas reinjection station has multiple punctures and leaks. In order to analyze the reasons for the failures, a macro inspection, hydrostatic pressure and blasting test were carried out on a new hose of the same specification. Phase organization analysis, macro inspection, physical and chemical inspection, scanning electron microscopy (SEM), energy spectrum analysis, metallographic analysis and composition analysis of the conveying medium were carried out on the two failed hoses. The results show that the hydrostatic pressure test of the same batch of the new hoses of this specification meets the requirements of the standard, however the burst pressure does not meet the requirements of the standard. The failure is caused by the welding quality problems at the joint connection, welding defects such as weld bead, incomplete penetration and welding slag. The existence of deformation-induced martensite is found in the metallographic structure of the failed hose corrugated tube. There is tensile stress in the service environment, and a high content of corrosive medium Cl- in the conveying medium. Under the action of internal stress, the internal corrosive medium causes corrugation, the tube undergoes stress corrosion, thus initiating corrosion cracks and propagating along the grain boundaries, leading to the cracks and failure accidents.

Analysis of the Reason for the Fracture of the Safety Valve Spring in the Anhydrous Hydrogen Fluoride Tank

This paper analyzes the fracture of the safety valve spring of an anhydrous hydrogen fluoride tank in a logistics unit through macro inspection, chemical composition analysis, metallographic inspection, hardness measurement, electron microscope scanning analysis, and other technical means to find the reason for the fracture of the safety valve spring. In addition, effective preventive measures are put forward to reduce and prevent the occurrence of such problems and improve the safety of the use of tank containers.

Mechanical Properties and Fracture Analysis of High Strength Bolts in Nuclear Power Plant

A high-strength bolt of a steel structure of a nuclear power plant failed and fell off. In order to determine the cause of the bolt’s fracture, a series of tests such as macro inspection, physical and chemical performance test, and microscopic analysis of the fracture were carried out on the failed bolt. The results show that the cause of bolt fracture is hydrogen embrittlement. Hydrogen infiltrated into the bolt during the phosphating process and the corrosion process during use, and then hydrogen continued to accumulate eventually causing hydrogen embrittlement fracture. Dehydrogenation treatment should be performed immediately after the phosphorylation treatment, and the anti-corrosion method of the bolt should be optimized, which is an effective measure to prevent the hydrogen embrittlement of high strength bolts.

Fracture Failure Analysis of the Energy Storage Spring of the Circuit Breaker in the 110kV Substation

Through a macro inspection, chemical composition analysis, hardness inspection, graphite carbon inspection and energy spectrum analysis, the reason for the break of the energy storage spring of the circuit breaker in a 110kV substation are analyzed. The results show that poor manufacturing technology and anti-corrosion technology of the spring are the main reason for its fracture. Corresponding control measures are put forward to avoid similar failures from happening again.

Corrosion analysis of angle steel used in 500kV transmission tower

Transmission tower is the load-bearing structure of high-voltage transmission line, and its stability is very important for the reliable operation of grid equipment. In recent years, the corrosion of transmission towers has become increasingly prominent due to long-term service in the harsh field, which seriously affects its service life. In this paper, the corroded angle steel of high-voltage power tower was studied by different physical and chemical testing methods such as macro inspection, metallographic analysis, mechanical property test, chemical composition analysis, energy spectrum analysisand scanning electron micrograph analysis. The result reveled that the galvanized protective layer of the angle steel was well preserved without corrosion damage, and the corrosion spot on surface of the tower materail was caused by the corrosion of other metal parts nearby and then the rusting outcome flowed with rain water to its surface.

Discussion and analysis on corrosion causes of metallic components used in transmission tower

With the rapid development of power grid and the continuous aggravation of heavy industry pollution, more and more attention would be paid to the corrosion of metallic components of transmission line. The chemical and electrochemical corrosion of transmission tower and its fittings would shorten the service life. Therefore, it requires regular anti-corrosion coating treatment or even overall replacement, which not only wastes a lot of financial and material resources, but also causes safety accidents. In this paper, different testing methods such as macro inspection, metallographic analysis and energy spectrum analysis were adopt to investigat and analyse corrosion behaviour of cotter pin, fitting, guyed rod and angle steel used in transmission tower. Additionally, corresponding anti-corrosion measures were put forward in order to improve the anti-corrosion performance of the metallic components and guarantee the safety and stability of transmission line.

Fracture failure analysis of conductive arm spring of isolation switch in 500kV substation

Through macro inspection, chemical composition analysis, hardness inspection, graphite carbon inspection, metallographic inspection, the causes of spring fracture on conductive arm of isolation switch in a 500kV substation were analyzed. The results show that poor manufacturing technology and anti-corrosion technology of the spring are the main reason for its fracture. Corresponding control measures are put forward to avoid similar failures from happening again.

Failure Analysis of Weld Cracking in External Cold Water Pipeline of Condenser in Converter Station

The cause of weld cracking in external cold water pipeline of condenser in a ±800kV converter station were analyzed by macro inspection, chemical composition analysis, hardness test, microstructure inspection, scanning electron microscopy and energy spectrum test methods.The results show that the main reason for the cracks is that the material and manufacturing process are not qualified, and the welding process is not good. Corresponding control measures are put forward to avoid similar failures from happening again.

Failure Analysis of Clamp Crack on TA Equipment in Converter Station

Through macro inspection, chemical composition analysis, hardness test, tensile performance test, microstructure inspection and scanning electron microscope analysis, the causes of clamp crack on TA equipment in the 500kV AC filter field of the ± 800kV converter station were analyzed. The results show that improper selection of the manufacturing process of the equipment clamps will cause more micro-defects inside it, leading to poor mechanical properties and excessive internal stress, which are the main causes of cracking. Corresponding measures are put forward to improve the manufacturing quality of equipment clamps, which can avoid similar failures from happening again.

Failure Analysis on Leakage of the Circumferential Weld of Steel 20 Buried Pipeline

Nowadays, the welding quality of circumferntial welds is the main influencing factor of the service behaviors of long-distance transport pipeline, and the accidents caused by the circumferential welding defects have get extensive attention. To figure out the leaking reason of circumferential weld of the steel 20 buried pipeline, with macro inspection, nondestructive testing, physical and chemical properties, methods of medium leakage and fracture analysis, we found that the welding defects in the weld toe are mainly responsible for pipeline leaking. The welding defects of circumferential weld destroy the continuity of welding, which result in the stress concentration and cracks. Under the combined action of corrosion, erosion, working stress and welding residual stress, the cracks extend along the welding weak areas and penetrates the welding metal, finally leading to the leakage failure of the welds, also some suggestions are given to prevent similar accidents.

Qualification of ITER PF6 helium inlet

The Poloidal Field (PF) coils are one of the main sub-systems of the ITER magnets. The PF6 coil is being manufactured by the Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP) as per the Poloidal Field coils cooperation agreement signed between ASIPP and Fusion for Energy (F4E). As one of the critical components, helium inlet locates on the innermost turn and supplies the coil with supercritical helium. During Tokamak operation, the helium inlet will undergo huge cyclic electromagnetic loads and thermal cycling during cooling down and warming up.This paper focus on the main steps of ITER PF6 helium inlet qualification. Helium inlet hole drilling and stainless steel wrapping removal were firstly been carried out. Helium inlet welding with full penetration by automatic welding machine was then performed, followed by leak proof test, non-destructive test, fatigue test and tomography test. At the end, the samples were sectioned for micro and macro inspection. The results show ITER PF6 helium inlet qualification has successfully met the requirements of PF procurement agreement(PA) and was approved by ITER IO.

Detection of Low-Contrast Defects in Optical Films Using Sigma-Based Segmentation Technique

Optical film is an important component for LCDs, cell phones and other mobile devices. It is crucial to ensure an optical films is defect-free. However, derive from the inherent translucent characteristic, many images of defects of optical films are low contrast. Low-contrast defects are notorious for their difficult to be detected. As some low-contrast defects are barely visible to human being without special training, it is indeed a challenging task to capture low-contrast defect images. To overcome the difficulty, we thoroughly investigated various of imaging and lighting technologies. After images have been captured successfully, we devided the captured defects, based on their sizes, into two categories, i.e. macro defects and micro defects. To detect both large and small defects, we set up a macro inspection system and a micro inspection system, respectively. In the study, we provide an easy to understand approach to reveal low-contrast defects. The experimental results showed that the proposed inspection system and method is capable of detecting low-contrast defects such as uneven coatings, streaks, white spots and foreign particles.

Process Optimization Using OPE-Master and CDU Master

OPE matching and CD-Uniformity control have become inevitable steps for most of high volume manufacturing(HVM) of a state-of-the-art devices. OPE matching is a step to match CDs of various patterns from different scanners or steppers. CD-Uniformity control is to stabilize CDs across exposure fields, across wafers and across lots, for HVMs. At a current OPE matching, one usually collects tool properties from each matching tool and import them into simulation software they are using to improve its prediction accuracy. However, generally speaking, this is a time and human resource consuming process, because data acquisition from scanners usually take a lot of time of both human and machine. Furthermore, what makes it more difficult is that an OPE matching, in most cases, requires several iterations. In this paper, we will introduce our latest software named OPE-Master. By employing the software, we can expect following merits. Firstly, with the help of the software, one can be able to automatically import machine properties. This means we can expedite the iterations without sacrifice of the accuracy. Secondly, one can also be able to get better solutions, because it uses all possible adjustment knobs, some of which are ones that unable to be accessed by a third party softwares, with the help of newly developed optimization algorithm that uses a hybrid method of nonlinear optimization and rigorous simulation. Finally, intuitive interface of the software makes it possible for an engineer without much optical simulation experiences to do an OPE matching simulation. In this paper, we will also introduce one of our latest software, called CDU-Master, which will be used to control CD uniformities for a HVM. CDU-Master can analys CDs from various metrology tools, such as, CD-SEMs, OCDs or a macro inspection tools(AMI, for example). CDU-Master can decompose CD errors into focus and dose errors and then derives parameters to correct CDs. One can expect extremely high accuracy of the decomposition, because, CD-SEM as an example, it uses all possible information such as CDs and pattern 3D structure information. The correction parameters, which may include very high order coefficients to be able to deal with very high spatial frequency distribution of errors across a field or across a wafer, will be converted into a format that can be recognized by scanners and then can be exported to scanners automatically, by the software.

Protective Properties Analysis of Oxide Skin by WOT in Supercritical Unit

This paper studied the different formation mechanism and the corrosion protection mechanism of oxide skin in the conditions of WOT and OT in the supercritical units. The WOT tube and OT tube of the high temperature superheater were detected by visual macro inspection, their microscopic structures were analyzed by electron microscopy and their elemental compositions were detected by EDS. The authors put forward steam oxidation mechanism of WOT and peroxide-chromium evaporation mechanism of OT. The test results were analyzed by chemical thermodynamics and chemical kinetics. The experiment and analysis proved that: the oxide skin of WOT’s tube retained the alloying elements and the design of protective structures, but the oxide skin of OT’s tube lost the alloying elements and it had not good protective properties. The studies had shown that: in compared of the WOT and OT, the WOT had a good corrosion protection and a significant advantage of preventing abnormal rapid growth of oxide skin, so WOT was the best choice for feed-water treatment.

Crack Analysis of Induction Heating Bent Pipe

There were 20 of 103 length of pipe found cracks on the extrados surface of the bent pipe made of Φ406.4×10mm L360 Longitudinal Submerged Arc Welding (LSAW) pipe, the cracks were mostly distributed in the extrados surface and the arc initial point of the bent pipe, the cracks were spindle-shaped and narrow at both ends with the longitudinal direction vertical to the axis of bent pipe. The mechanism and the causes of the cracks were studied by macro inspection, mechanical property test, microscope, scanning electron microscopy and energy spectrum analysis, which shown that the cracks were result from the contamination of copper or its alloy during or before the bent pipe production. The contaminated material like copper infiltrated and diffused into the base metal at high temperature, and could hardly stead to and transfer the normal stress from the base metal where the inertial crack was shaped. Meanwhile, the new crack was formed at the tip of inertial crack after the new infiltration and diffusion under the condition of both high temperature and tensile stress, so that the crack progressed and extended in this way.

Failure of 9Cr-1Mo tubes in a feed furnace of dehydrogenation unit

The successful uses of 9Cr-1Mo steel in boilers, superheaters and furnaces have been well established; however, the unusual failure of this material in a feed furnace of dehydrogenation unit in linear alkyl benzene plant is reported here. Extensive experiments such as chemical composition examination, macro inspection, metallurgical observation, scanning electron microscopy (SEM) and energy dispersive spectrum (EDS) analysis, together with mechanical tests, were conducted on the failed material and the results are presented. The failure described as pitting and cracking of the 9Cr-1Mo tubes is stated to be caused by serious carburization combined with hydrogen corrosion. The great stresses developed by volume changes in the carburization of the metal as well as the decomposition of the carbides are believed to be largely responsible for the pitting and cracking of the tubes.