Results Of Non-destructive Tests Research Articles

Однопроходная электродуговая сварка под тонким слоем шлака толстолистовых конструкций стали 09Г2С

Introduction. The technology of single-pass arc welding under a thin layer of slag (AST) of thick plate welded structures in the thermal and nuclear engineering is considered. The structure material is 09G2S steel. The work objective is the experimental study on the applicability of the AST method instead of the automatic welding under flux (AWF) and electroslag welding (ESW) under manufacturing the package units of the power plants. Materials and Methods. The technology is developed on the basis of the calculation results of the thermal welding mode (thermal cycle parameters and welding mode settings). Test joint weld-samples, 100 mm thick, are made of 09G2S lowcarbon low-alloy steel. Welding is performed on the certified equipment of “EMC-Atommash” JSC. The welded joints quality is assessed on the standard control results by the following techniques: magnetic-particle testing (MPT), ultrasonic control (USC) and radiographic testing (RT). The non-destructive testing results were supplemented with the metallographic study data. To investigate the nature of the weld metal crystallization along the length of the weld, the macrotemplates were cut out mechanically from the middle through-the-thickness and at the distance of 10 mm from the surface. The technique and installation of “TCS-1” for simulating the thermal cycle of the metal welding of the heat affected zone (HAZ) of the welded joints; standard methods for determining mechanical properties; hardness and microhardness indices; and method for determining the grain size in micrographs according to GOST 5639-82 were used in the experiments. The microstructure was studied with MMP-2P and Reichert optical microscopes with increase up to thousandfolds. Besides, the distribution pattern and identification of the second phases of nonmetallics; welded samples and samples modeling the HAZ metal for the notch sensitivity; structure stability and welding cracking resistance were studied through the replica technique using the EMV-100LM electron microscope. Research Results. Based on the thermal calculation results and the HAZ metal modeling, the optimum values of the heat input and welding variables are validated and experimentally verified. The welded joints quality is estimated by the nondestructive and destructive methods. The effect of the welding method on the structure, quality and mechanical properties of the welded joints is established. Discussion and Conclusions. Positive results of the theoretical and experimental studies are obtained. They indicate the technological and economic efficiency of the AST method application (instead of AWF and ESW) under manufacturing the 100 mm thick welded joints of 09G2S low-alloy steel. Moderate heat input in AST allows for the one-pass forming of a welded joint with better fine-grained structure and higher mechanical characteristics as compared to the ESW and AWF. Recommendations on the use of the AST technique in the welding production are given.

Non-destructive testing of automotive heat exchangers

The paper presents the results of non-destructive testing to the final control of automotive heat exchangers, which must meet a number of technological and exploitative requirements resulting from their working conditions. For the observation of images of heat exchangers, verification of geometrical dimensions and identification of surface and volume defects, the used methods were: computed tomography (highresolution microtomograph Phoenix v|tome|x), three-dimensional optical scanning (3D GOM ATOS III optical scanner), coordinate measuring technique (coordinate measuring machine Hexagon Global Performance 122210). The effectiveness of nondestructive testing in industrial conditions was assessed and the directions of further research in this area were indicated.

Types of Surface Impurities versus the Quality of Brazed Joints

Brazing is one of the primary joining processes increasingly often applied in industry. Because of their mechanical properties, overlap joints are particularly popular when making brazed structures. The use of brazed joints in structures of critical importance requires that particular attention be paid to joint quality, e.g. by the appropriate cleaning of surfaces to be joined. The article presents results of non-destructive tests of brazed joints made in steel S235JRG2. Surfaces used in the tests were deliberately contaminated to simulate the presence of welding imperfections. Afterwards, the test specimens were subjected to non-destructive (visual and radiographic) tests aimed to determine the effect of surface impurities on the quality of brazed joints.

Analiza trenutnog stanja i ocena čvrstoće cevovoda na hidroelektrani Pirot

Hydro power plant Pirot, which was built in 1990, is an accumulation-derivative power plant, which consists of 2 above-ground vertical hydroelectric generating sets that contain Francis turbines with nominal power of 41,5 MW, manufactured in Czech Republic, a tunnel and a sunken pipeline with overall length of 2.030 m and diameter that ranges from 3.000 to 3.500 m. Pipes have been made of S275J2G3 steel. Pipe wall is 22 mm thick. Maximum pressure of 2.5 MPa occurs in front of the turbine cover. Geodetic measurements have been conducted permanently from the day the assembly was finished and pipeline was put into service, both when pipeline is empty and unloaded by hydrostatic pressure and when it is full. Analysis of obtained data regarding the movements along the pipeline route showed that from year 2003 there are significantly higher differences in movements comparing the situations when the pipeline is full and when it is empty in comparison with the previous period. This paper contains the analysis of current state and strength evaluation of the pipeline as a whole on the basis of results of non-destructive tests performed on the vital butt - welded joint in the curvature area at chainage 1+263 m (visual testing, magnetic particle testing, penetrant testing, ultrasonic testing, radiographic testing, metallographic replication testing).

Remaining life assessment for boiler tubes affected by combined effect of wall thinning and overheating

Boilers, the most troublesome components of electric power, chemical and processing plants generate high costs in unscheduled shutdowns, repairs and power replacement. Every occurrence of ruptured tubes leads to emergency shutdown of the entire plant. This paper describes the joint international effort to develop faster and more efficient methods for condition assessment and remaining life prediction for boiler tubes made of low-carbon steel. Authors have undertaken a systematic research with the major objective to correlate the results of combined nondestructive testing (NDT) with condition assessment of boiler tubes. The evaluation included non-contact wall thickness measurement with EMAT technology plus internal oxide layer measurement with specialized ultrasonics. While the first method shows the remaining tube wall thickness, thus allowing calculating total stress, the latter one has the potential to characterize microstructure degradation, which up to now could only be determined by destructive analysis. The special attention was directed towards identification and analysis of creep damage due to overheating. In recent years, techniques were developed to identify heat damage by measuring the thickness of internal oxide scale because even a thin scale can seriously impede heat transfer causing elevation of temperature in tube wall. A combined effect of wall thinning and the “degree of overheating” on tube remaining life was investigated. The uniqueness of this work lies in one of the first attempts to develop and validate a tool for methodology for condition assessment and remaining life prediction, for Steel20 tube material, while most of previous authors had concentrated on Cr-Mo steels. Another contribution is the combined treatment of two different damage mechanisms and practical utilization of two various NDT techniques. To-date, both results are treated separately, and consequently separate reject criteria exist for overheating and separate for wall thinning. As a result of work presented in this paper, a procedure was recommended to calculate the tube remaining life based on the results of two ultrasonic tests.

Investigation of Strength Characteristics of Natural Stones in Ürgüp (Nevşehir/Turkey)

Natural Stones of Urgup (Nevsehir) have used commonly both indoor and outdoor due to easy give form at the stone quarry. That’s why some geotechnical and geomechanical tests must be done in order to determine quality separation and strength characterisation. Destructive and non-destructive tests were done on the five different colored and featured samples (10×10×10 cm 3 ) named Visne, Devetuyu, Gulkurusu, Kirli Beyaz and Sari obtained from study area. The uniaxial stress test was made in the frame of destructive tests. Schmidt hammer and ultrasound tests were applied in the frame of non-destructive tests. Results of destructive and non-destructive tests were compared and weaknesses and advantages of all methods were discussed. One of the samples named Sari has more strength according to other samples. Gulkurusu and Kirli Beyaz samples have the lowest strength. Similarly, Schmidt hammer and ultrasound measurements gave high strength results. Because of destructive and non-destructive testing methods from different natural stone samples with non-uniform mineral combination were in accordance. Non-destructive testing methods can be used for strength characterisation of natural stones. In this case, geomechanical features and quality ranks can be determined with in-situ tests without carry the samples to laboratories.

Improved model for detection of homogeneous production batches of electronic components

Supplying the electronic units of the complex technical systems with electronic devices of the proper quality is one of the most important problems for increasing the whole system reliability. Moreover, for reaching the highest reliability of an electronic unit, the electronic devices of the same type must have equal characteristics which assure their coherent operation. The highest homogeneity of the characteristics is reached if the electronic devices are manufactured as a single production batch. Moreover, each production batch must contain homogeneous raw materials. In this paper, we propose an improved model for detecting the homogeneous production batches of shipped lot of electronic components based on implementing the kurtosis criterion for the results of non-destructive testing performed for each lot of electronic devices used in the space industry.

Non-destructive experimentation: Dynamic identification of multi-leaf masonry walls damaged and consolidated

Abstract The dynamic monitoring of multi-leaf masonry wall is here proposed. The results of non-destructive tests carried out in this work are a first part of a wider testing campaign aimed at verifying the structural performance of masonry walls. Multi-leaf masonry walls constitute the composite construction typology most widely adopted in historic buildings. This aspect, together with the intrinsic structural complexity, heterogeneity and irregularity, directs the present research towards a topic not yet sufficiently investigated by the scientific community. In this paper, the case of multi-leaf masonry wall has been investigated, and with the aim of reproducing historical buildings structural elements, three different typologies of multi-leaf masonry walls have been considered: (i) full infill, (ii) damaged infill, (iii) consolidated infill. Several masonry specimens of the above-described typologies have been built and tested in lab. The dynamic parameters, such as frequencies, modal shapes and damping ratios have been identified through the output-only procedure and the data were processed through the Least Square Complex Frequency (LSFC) estimator; the analysis of results allowed to evaluate the structural integrity, the efficacious of consolidating intervention and the potential performance mechanisms of different complex multi-leaf masonry walls. Experimental results are compared with numerical Finite Elements models. Composite multi-leaf masonry is modeled as an equivalent continuum obtained through a full 3D homogenization procedure. The mechanical properties of component materials have been obtained in lab by tests and then used to model the masonry at the micro-scale in order to derive the mechanical properties to be adopted at macro-scale. A parametric natural frequencies analysis is performed in order to calibrate the model by the comparison whit the experimental measures.

Influência de variáveis nos resultados de ensaios não destrutivos em estruturas de concreto armado

The aim of this paper is to present the result of a study of the influence of some variables on the results of nondestructive testing of concrete, sclerometry (rebound hammer) and ultrasonic pulse velocity (UPV), specially in: Aggregates' size (DMA), concrete's moisture, casting concrete, and transducers' space. Moisture in concrete was obtained by controlled sprinkling water. The tests were conducted on six years old concrete blocks, and two years old reinforced concrete beams. Water/cement ratio of concrete blocks was maintained and DMA of coarse aggregates were 9.5 mm, 19.0 mm and 25.0 mm. The results of UPV revealed that blocks with the biggest DMA had lower UPV, the middle concrete layer presented bigger value of UPV than others. The UPV increased when the surface was sprinkled or the transducers space increased, for blocks and beams. The smaller rebound index was on blocks containing aggregates with the biggest DMA. For blocks and beams, the rebound index decreased when superficial moisture increased. Keywords: Nondestructive testing, ultrasonic pulse velocity, sclerometry (rebound hammer).

Analysis of the single and combined non-destructive test approaches for on-site concrete strength assessment: General statements based on a real case-study

The evaluation of the compressive strength of concrete in existing structures by coring is expensive, technically difficult in certain cases, and even impossible in others. The use of non-destructive testing (NDT) is an interesting alternative method (i.e. affordable cost, portable, fast, etc.). However, the NDT estimation of strength requires a procedure of calibration of the model between NDT and compressive strength. The robustness of this calibration is a crucial point allowing better choice of the optimal number of cores. Studies which treat the calibration of proposed models are often based on laboratory experiments or synthetic data. The present study aims at identifying and optimizing the methodology of the calibration model on site. This paper is based on a broad campaign of auscultation using NDT (Rebound and Ultrasound) and coring on an existing construction with 205 triplets of data (strengths and NDT results). Statistical data analysis enables to quantify the role of: the number of cores (NC) used for the calibration, the use of only one or two-combined NDT techniques and the calibration method. The conclusions are focused on the improvement of the relevance and the effectiveness of NDT techniques in such operational situations.

Results of Non-Destructive and Destructive Tests of Welded Joints Made of Heat-Resistant Cast Steel GX40NiCrSiNb35-25 in Welding Procedure Qualification

Results of Non-Destructive and Destructive Tests of Welded Joints Made of Heat-Resistant Cast Steel GX40NiCrSiNb35-25 in Welding Procedure Qualification

Combination Non-Destructive Test (NDT) Method for Early Damage Detection and Condition Assessment of Boiler Tubes

Boilers, the most troublesome components of electric power, chemical and processing plants generate high costs in unscheduled shutdowns, repairs and power replacement. Every occurrence of ruptured tubes leads to emergency shutdown of the entire plant. This paper describes the joint international effort to develop faster and more efficient methods for condition assessment and remaining life prediction for boiler tubes. The work was performed under the grant from Kazakhstan Ministry of Education and Science.The authors have visited a number of coal-fired electric plants throughout Central Asia and found that a combination of wall thinning and overheating were major damage mechanisms contributing to boiler tube failures. The periodic inspection of boiler tubes include ultrasonic measurement of remaining wall thickness and in many cases, it involves cutting tube segments and performing metallurgical analysis for loss of original strength due to overheating. Systematic research was undertaken with the objective to correlate the results of combined non-destructive testing (NDT) with condition assessment of boiler tubes. The evaluation included non-contact wall thickness measurement with EMAT technology plus internal oxide layer measurement with specialized ultrasonics. The first method shows the remaining tube wall thickness, thus allowing to calculate total stress, and the latter one has the potential to indirectly characterize microstructure degradation, which up to now could only be determined by destructive analysis. The existing tube removal criteria are treating each damage mechanism separately while in reality, a combined effect of wall thinning and the “degree of overheating” decides about true condition of a tube. The procedure that utilizes the results of both described NDT methods was developed for improved methodology to assess tube condition and to predict its remaining life.

Analiza trenutnog stanja i ocena integriteta cevovoda na hidroelektrani Pirot

Hydro power plant Pirot, which was built in 1990, is an accumulation-derivative power plant, which consists of 2 above-ground vertical hydroelectric generating sets that contain Francis turbines with nominal power of 41,5 MW, manufactured in Czech Republic, a tunnel and a sunken pipeline with overall length of 2.030 m and diameter that ranges from 3.000 to 3.500 m. Pipes have been made of S275J2G3 steel. Pipe wall is 22 mm thick. Maximum pressure of 2.5 MPa occurs in front of the turbine cover. Pipeline has been designed and built without anchor blocks at curvatures, which is a rarity elsewhere. Geodetic measurements have been conducted permanently from the day the assembly was finished and pipeline was put into service, both when pipeline is empty and unloaded by hydrostatic pressure and when it is full. Analysis of obtained data regarding the movements along the pipeline route showed that from year 2003 there are significantly higher differences in movements comparing the situations when the pipeline is full and when it is empty in comparison with the previous period. Those differences primarily refer to tangential movements of vertices marked with numbers 6, 7 and 8, which, compared to the period until year 2002, are in the range from 3 mm for vertex 8 to 5 mm for vertex 6. Apart from geodetic measurements, the measurement of pipe diameter in 2 directions is also being carried out permanently. Those data show that from year 2003 the diameter in horizontal direction started to increase significantly, while at the same time the diameter in vertical direction started to decrease less significantly. This paper contains the analysis of current state and integrity evaluation of the pipeline as a whole on the basis of results of non-destructive tests performed on the vital butt-welded joint in the curvature area at chainage 1+263 m (visual testing, magnetic particle testing, penetrant testing, ultrasonic testing, radiographic testing, metallographic replication testing.

APPLICATION OF X-RAY METHOD FOR TESTING MUNITIONS

Some results of non-destructive tests of explosive ordnance (munitions) used by the Polish Armed Forces and performed by X-ray apparatus MU-17F-225-9 from YXLON are presented in the paper. Tests were performed in diagnostic purposes as they are significant for munitions status evaluation process. Received results decide also about the selection of final testing methodology.

Analysis of reflected signals in testing cylindrical specimens by the multiple reflection echo-shadow method

In this paper, we present the results of correlation, spectral, and probabilistic-statistical analyses of signals in the flaw inspection of cylindrical specimens by the multiple reflection echo-shadow method, and establish new informative parameters for the purpose of their integrated use to improve the reliability of nondestructive testing results.

조기강도 콘크리트의 압축강도 추정을 위한 비파괴검사 실험식의 제안

In construction field, it used various technique for concrete formwork. Part of them, non-destructive test has been conducted to estimate a compressive strength of concrete easily such as rebound method and ultrasonic pulse velocity method etc. Former research has recommend proposed equation based on experimental data to investigate strength of concrete but it was sometimes deferent actual value of that from in field because of the few of data in case of early strength concrete. In this study, an experiment was conducted to analyze strength properties for early strength concrete using cylinder mold and rectangular specimen. And compressive strength of concrete was tested by non-destructive test, and calculated by the equation proposed former research. As a result, the non-destructive test results showed approximately 70 percent of the failure test value for all conditions, and worse reliability was obtained for high strength concrete samples when the ultrasonic pulse velocity method was used. Based on the scope of this study, the experimental equation for estimating compressive strength of early strength concrete from 24MPa to 60MPa was proposed.

Properties and Microstructure of Laser Welded VM12-SHC Steel Pipes Joints

Abstract Paper presents results of microstructure and tests of welded joints of new generation VM12-SHC martensitic steel using high power CO2 laser (LBW method) with bifocal welding head. VM12-SHC is dedicated to energetic installation material, designed to replace currently used. High content of chromium and others alloying elements improve its resistance and strength characteristic. Use of VM12-SHC steel for production of the superheaters, heating chambers and walls in steam boilers resulted in various weldability researches. In article are presented results of destructive and non-destructive tests. For destructive: static bending and Vickers hardness tests, and for non-destructive: VT, RT, UT, micro and macroscopic tests were performed.

A novel vibration based non-destructive testing for predicting glass fibre/matrix volume fraction in composites using a neural network model

This study proposes a novel approach to determine the fibre volume fraction in composites using vibration based non-destructive technique with a neural network. Currently, the volume fraction of a glass fibre/matrix based composite material is assessed using destructive techniques. Instead of changing or destroying the structure, a new non-destructive approach based on vibration analysis is proposed. Complete experimental protocols were developed to capture the vibration pattern. An auto-regressive model was developed as a feature extraction tool to classify the fibre volume fractions and as a pole tracking algorithm. The classification performances were within the range of 90–98%. For NDT method to be efficient, the classification results were then compared with destructive burn-out technique. The results of non-destructive test showed good agreement with those obtained through destructive test suggesting that the proposed method is an alternative to ASTM D2584-11 for determining the volume fraction of a glass fibre/matrix composite.

The probabilistic characteristics of estimation of the residual strength and operation lifetime of steel wire rope based on the results of non-destructive testing

This article describes a procedure for the probabilistic estimation of the strength indices of steel wire ropes on the basis of the data of magnetic non-destructive testing. The proposed method for the determination of probabilistic characteristics undetection an existing fault of a heterogeneous wire rope structure and the false detection of a fault. The obtained probabilistic estimates of errors of nondestructive testing have been applied for calculations of high-risk and conservative scenarios of the variation of the strength and remaining lifetime of wire rope during its non-fault operation lifetime.

Impact of the Direction of Non-destructive Test with Respect to the Annual Growth Rings of Pine Wood

Wood maintains remarkable durability under optimum conditions. However, it erodes faster than other construction materials in the circumstances of average usage of civil structures. Therefore, built features made of wood, especially historical features and structures, require repairs and reinforcements more frequently than those made of other materials. Non-destructive testing is usually carried out in structures that are currently in use and is aimed at early detection of failures and taking appropriate remedial measures. It can be generally assumed that diagnostic testing of wood is a difficult process due to its structure. However, the ability to identify the current strength parameters of wooden structural components makes it possible to properly assess their suitability for further use and design appropriate reinforcement and reconstruction methods. However, it should be noted that non-destructive test results are influenced by many factors such as: the type of wood, its defects, moisture content, age and the direction of test in relation to annual growth rings as well as microbial agents. This paper addresses the evaluation of the mechanical properties of pine wood under testing perpendicular, vertical and diagonal to the annual growth rings. Furthermore, the paper presents problems related to direction of test content on the results of non-destructive testing (sclerometer, ultrasonic tests and cutting resistance measurements). Based on the survey, it was found that the orientation of the test direction with respect to the annual growth rings must be taken into account in the course of the analysis using non-destructive methods.