scholarly journals Preparation and properties of low cement castable sintered at different temperatures

2009 ◽  
Vol 3 (4) ◽  
pp. 191-196 ◽  
Author(s):  
Sanja Martinovic ◽  
Jelena Majstrovic ◽  
Velislav Vidojkovic ◽  
Tatjana Volkov-Husovic

The low cement high alumina castable (LCC) studied in this paper was synthesised, cured and then treated at different sintering temperatures. Since any inhomogeneity introduced during the castable preparation can remain inside the material degrading its properties and therefore the quality during service life, particular attention was given to the processing procedure in order to produce the material with the optimum characteristics. Composition of the castable regarding particle size distribution was adjusted according to the Andreassen's packing model. The samples were sintered at 1100, 1300 and 1600?C for three hours. Influence of the different sintering temperatures on the castable properties is discussed. Compressive and flexural strengths were determined by destructive testing method, while the water immersion method was used for determination of the bulk density and the water absorption. Changes of elastic properties and microstructure (porosity) were observed by the non-destructive testing methods, ultrasonic measurements and image analysis. Based on the results, it can be concluded that sintering temperature has strong influence on the properties of the LCC. Exceptionally good properties were obtained for the sample sintered at 1600?C, but it should be highlighted that the samples treated at 1100 and 1300?C were provided with good properties, too. This should not be neglected because of the energy saving importance, in cases where the material sintered at lower temperature satisfies the application requirements. .

2021 ◽  
pp. 34-41
Author(s):  
V. A. Zaznobin ◽  
A. V. Nekrasov ◽  
A. V. Pankratov

Statistics of accidents and incidents on main gas pipelines in recent years indicate that almost half of the technogenic events occur due to depressurization in the area of annular welded joints, mainly joints containing defects made during construction and installation work during the construction of gas pipelines. The assessment of the degree of danger and the timing of external inspection and repair or replacement of defective annular welded joints largely depends on the quality of non-destructive testing, the correct identification of the types of defects and the objective determination of their geometric dimensions. To increase the reliability of the assessment of the degree of danger of the detected defects, it is necessary to use additional control methods, in particular, destructive ones. The paper presents the results of surveys and tests of metal fragments of annular welded joints of main gas pipelines containing transverse cracks of annular welded joints in order to determine the causes of the formation of these defects and to assess the degree of danger of the detected transverse cracks of the installation welds of main gas pipelines.


2021 ◽  
Vol 87 (9) ◽  
pp. 44-49
Author(s):  
D. A. Kuzmin

Discontinuities in the products that occur during manufacture, mounting or upon operation can be missed during non-destructive testing which do not provide their complete detectability at a current level of the technology. Therefore, it is necessary to take into account that certain structural elements may have discontinuities of significant dimensions. We present the results of using the methods of probability theory in studying the residual imperfections that remains in the structure after non-destructive control and repair of the previously identified defects. We used the results of operational control of units carried out by ultrasonic and radiographic methods. We present a method for determining a multifactorial coefficient that takes into account the detectability of defects, the number of control procedures and the errors in the instrumentation and methodological support, as well as a generalized equation for the probability distribution of detecting discontinuities. The developed approach provides assessing of the level of damage to the studied objects, their classification proceeding from the quantitative data and determination of the values of postulated discontinuities for deterministic calculations. The results obtained can be used to improve the methods of monitoring NPP facilities.


2005 ◽  
Vol 59 (1-2) ◽  
pp. 32-35
Author(s):  
Slavica Mihajlovic ◽  
Zivko Sekulic ◽  
Milan Petrov

The results of laboratory investigations of the possibility to obtain coated limestone for the production of PVC-products are presented in this paper. Limestone from the "Vencac" deposit (Arandjelovac, Serbia and Montenegro) was used as the raw material. The investigations were carried out in two phases: obtaining the coated limestone and determination of the degree of coating. The results of the investigations showed that successful coating of the surface of the limestone particles with Ca-stearate (Ca-stearate content 3%) was achieved in a vibro mill with rings and the obtained degree of coating was higher than 95%. The coating degree was determined in transmitted light by a polarization microscope applying the immersion method (water immersion).


2004 ◽  
Vol 443-444 ◽  
pp. 31-34
Author(s):  
Giovanni Berti ◽  
Rob Delhez ◽  
S. Norval ◽  
B. Peplinski ◽  
E. Tolle ◽  
...  

This paper outlines the standardisation process for the XRPD method that is currently being considered by a Working Group (WG10) of Technical Committee 138 "Non-destructive Testing" of the European Committee for Standardisation CEN. Several Standard Documents are on the verge of being released. These documents concern the general principles of (X-ray) diffraction, its terminology, and the basic procedures applied. Another document concerns the instruments used and it offers procedures to characterise and control the performance of an X-ray diffractometer properly. It is intended to issue Standard Documents on specific methods, e.g. determination of residual stresses. In fact work is in progress on this subject. The Standard Documents can be used by industry, government organisations, and research centres with activities related to safety, health and the environment, as well as for educational purposes.


2010 ◽  
Vol 452-453 ◽  
pp. 129-132
Author(s):  
Paola Antonaci ◽  
Pietro G. Bocca ◽  
Davide Masera

The paper presents the results of an experimental investigation conducted on bricks. Prism-shaped specimens were produced. Laboratory tests were carried out at the Non-Destructive Testing Laboratory of the Politecnico di Torino. They were subjected to static compressive tests for the determination of their mechanical properties and cyclic compressive tests for the analysis of their fatigue behaviour. The aim of this work is to apply a failure criterion based on the observation of the static and cyclic curves to estimate the fatigue life and the long-term behaviour of the brick. Subsequently, it will be possible to give a relation between the static-displacement and cyclic-displacement of the material tested.


Author(s):  
Guy Baylac ◽  
Ian Roberrts ◽  
Erik Zeelenberg

This paper discusses the non destructive testing (NDT) of unfired pressure vessels made of ductile and tough steels, as contained in Part 5 of the European standard EN 13445:2002. The concept and use of testing groups along with “satisfactory experience” in welding are presented. Also the background and rationale for the determination of standards used for NDT methods, characterisation and acceptance criteria are discussed in detail. Benefits for the pressure equipment industry are emphasised.


Author(s):  
Yasuhiro Yuguchi ◽  
Taiji Hirasawa

This paper describes development and application of Phased Array Ultrasonic Testing (UT) and Remotely Operated Vehicles (ROV) for In-Vessel Internals Inspection. Stress Corrosion Crack (SCC) on reactor internals is one of the most important issues since 1990s, and demand to inspect the reactor internals is increasing. Instrument manufactures and inspection venders have developed and applied 1) Phased Array UT technologies and technique as one of our Non-Destructive Examination (NDE) technologies, 2) several kinds of ROVs and special tools for probe delivery and positioning. They are available and effective in In-Vessel Inspection (IVI) and maintenance, which shall be conducted in the narrow room under water. Furthermore, the UT technique for Alloy 182 weld that used to be difficult to detect and size flaws was developed and deployed in the BWR IVI. UT experiences in reactor vessels are increasing in recent years. An immersion technique by Phased Array UT is a key to perform the In-vessel UT on a complex geometric surface to be inspected, and to achieve very wide accessible range by ROVs or simple special tools efficiently. Advantages of the water immersion method and a ROV development result are shown in this paper. Particularly, TOSHIBA developed a flat type ROV for Shroud (Shroud ROV), which can be held against the surface of the shroud by thrusting propellers and scan mechanically through narrow gap within 2 inches {50mm}. The ROV’s positioning accuracy and applications for Shroud UT are shown. As the field experience, this introduces the UT results for CRD Stub tube Alloy 182 weld that is located on the vessel bottom head in Hamaoka UNIT 1 of Chubu Electric Power Company in Japan. An axial SCC flaw was detected by underwater visual testing, after the CRD stub tube leakage was detected. Then UT examination for the flaw was accomplished on the Alloy 182 weld in the vessel. We evaluated that the flaw penetrated into the weld metal of the CRD stub tube-pat weld and didn’t propagate into the low alloy of Reactor Pressure Vessel base metal. After UT sizing, the CRD stub tube was removed and replaced. The examination result was proven to have a good agreement with the actual crack depth. As a result, the efficiency of our Phased Array Technique was confirmed. As the other immersion method application, UT coverage example and accessible range for Shroud inspection are shown.


2016 ◽  
Vol 825 ◽  
pp. 23-26
Author(s):  
Pavel Klapálek ◽  
Lenka Melzerová

This article is focused on GLULAM (glued laminated timber) beams and determination of their properties by using non-destructive method. This text is mainly focused just on part of more complex research of glued laminated timber beams. This text is focused on non-destructive method, which is the method of spike that uses device called Pilodyn 6J for measurement. Results of this method are in form of Young ́s modulus of elasticity. This article will describe how the method of spike works, with basic description, describes the tested material and compare the results of testing. In the conclusion we discuss the results, make conclusions and describe the way of our further research of glued laminated timber beams.


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