scholarly journals Dimensional effect when measuring Martens hardness

2021 ◽  
pp. 128
Author(s):  
Vasyl Moshchenok ◽  
Lyidmila Kostina ◽  
Denis Pluzhnikov
Keyword(s):  
Service Life ◽  
Functional Dependence ◽  
Test Method ◽  
Structural Defects ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
High Productivity ◽  
Dimensional Effect ◽  
Meyer Equation ◽  
Non Destructive

One of the most common methods of non-destructive testing, hardness testing, is used to evaluate the properties of materials. This is due to the ease of measurement and testing of the finished part, which will be used in the future, high productivity of the method, the ability to assess other mechanical properties of the material: elasticity, creep, tensile strength. An important aspect in the study of the hardness using in the range the Berkovich and Vickers indenters, which are more consistent with non-destructive testing, while the methods of Brinell and Rockwell leave quite large deformations, in our opinion, which further promote the development of structural defects and reduce the service life, which are not acceptable in critical products. Due to the improvement of product manufacturability, more and more manufacturers are trying to minimize the size of the part, while increasing their performance by applying a reinforced layer, which, in turn, should seek to reduce the thickness with increased service life. It is also impossible to study the hardness of very small products in the micro range due to the large mismatch between the dimensions of the product under test and the test method. In our opinion, the study of hardness by the Berkovich method in comparison with the Vickers method is more expedient for use with the same physicochemical properties of the material because of a larger scatter of hardness values between the compared methods, although they should be almost the same, with a small difference. An important omission to a certain year was the dimensional effect. Goal. The aim of the study is to assess the nature of the change in hardness with increasing load on the indenter, using the functional dependence of the hardness on the depth of the indenter. For this purpose, it is necessary to establish such connection for an indenter of various geometry. In this regard, we consider it appropriate to check the validity of the Meyer equation, which relates the load to the size of the imprint, for different indenters and materials. Results. When the hardness is calculated according to the Martens scales, the Vickers and Berkovich indenters are applied to the function of the surface area of the working part of the tip. An important factor of the consistency of the results in the increase in hardness is the small effect. The reasons for this can be very negligible. The sizeable effect is significantly infused into the results of increasing hardness, changing from 2,5 to 3,0 folds.

Comparison and Analysis of Effective Guided Wave Standards Between GB and ASTM

2019 ◽  
Author(s):  
Ju Ding ◽  
Min Zhang ◽  
Shu-hong Liu ◽  
Chen-huai Tang ◽  
Xu-chen Zhu ◽  
...  
Keyword(s):  
Thermal Power ◽  
Guided Wave ◽  
Test Method ◽  
Amplitude Curve ◽  
Non Destructive Testing ◽  
Ultrasound Guided ◽  
Destructive Testing ◽  
Wave Detection ◽  
Ultrasonic Guided Wave ◽  
Non Destructive

Abstract This paper discusses four different ultrasonic guided wave standards. Three of them are China’s national standards or industry standards: GB/T 31211-2014 “Nondestructive Testing Ultrasound Guided Wave Detection”, GB/T 28704-2012“Non-destructive testing—Test method for ultrasonic guided wave testing based on magnetostrictive effects”, and DL/T 1452-2015 “Thermal Power Pipeline Ultrasound Guided Wave Detection”. The another one is ASTM E2929:“Standard Practice for Guided Wave Testing of Above Ground Steel Piping with Magnetostrictive Transfusion”. Through six aspects in this article, including testing application scope, preliminary requirements, standard specimen and comparative specimen, distant amplitude curve and time gain curve, the existing difference between China and America is obvious and diversity. It is necessary to explore the underlying reasons for the connection of Chinese code and international code in the field of Non-destructive testing. During the standardization, anyone of the standard should be actually compared on the presentation of chart, and the verification and comparison of results, and lists the similarities and differences of each part based on GB31211. This paper provides reference for China to integrate with foreign standards in the field of ultrasonic guided wave detection of pressure vessel and pipelines.

scholarly journals Non-Destructive Diagnostic Methods for Fire-Side Corrosion Risk Assessment of Industrial Scale Boilers, Burning Low Quality Solid Biofuels—A Mini Review

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7132
Author(s):  
Tomasz Hardy ◽  
Amit Arora ◽  
Halina Pawlak-Kruczek ◽  
Wojciech Rafajłowicz ◽  
Jerzy Wietrzych ◽  
...  
Keyword(s):  
Diagnostic Techniques ◽  
Diagnostic Methods ◽  
Structural Defects ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Solid Biofuels ◽  
Low Emission ◽  
Increased Risk ◽  
Corrosion Risk ◽  
Non Destructive

The use of low-emission combustion technologies in power boilers has contributed to a significant increase in the rate of high-temperature corrosion in boilers and increased risk of failure. The use of low quality biomass and waste, caused by the current policies pressing on the decarbonization of the energy generation sector, might exacerbate this problem. Additionally, all of the effects of the valorization techniques on the inorganic fraction of the solid fuel have become an additional uncertainty. As a result, fast and reliable corrosion diagnostic techniques are slowly becoming a necessity to maintain the security of the energy supply for the power grid. Non-destructive testing methods (NDT) are helpful in detecting these threats. The most important NDT methods, which can be used to assess the degree of corrosion of boiler tubes, detection of the tubes’ surface roughness and the internal structural defects, have been presented in the paper. The idea of the use of optical techniques in the initial diagnosis of boiler evaporators’ surface conditions has also been presented.

scholarly journals The Defect Analysis of Carbonsteel Pipe Welding Connections Using Non-Destructive Testing with the Penetrant Test Method

2020 ◽  
Vol 5 (1) ◽  
pp. 38-47
Author(s):  
Nur Ichsan Sumardani ◽  
Ngainun Ibnu Setiawan ◽  
Bebeh Wahid Nuryadin ◽  
Dadan Sumardani
Keyword(s):  
Surface Defects ◽  
Welding Process ◽  
Test Method ◽  
Test Results ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Pipe Welding ◽  
Materials Used ◽  
Non Destructive ◽  
Penetrant Testing

In a welding process carried out on metallic materials is sometimes found defects in the material being tested, it is caused by many factors, such as the lack of good materials used and the lack of perfection of the welding process. At testing, it aims to know the surface defects in carbonsteel pipes to know the defects arising after welding. This test is performed with non-destructive tests (NDT) using Dye Penetrant testing method. This test uses 3 types of liquids, including; Cleaner, Penetrant, and developer. The results of these tests will then be observed whether defects occur after welding and what factors affect it. From the test, results there are known 10 locations defects on the surface of the carbonsteel pipe welding with a type of rounded indication of defects that are then followed up by re-welding on indications of such defects.

scholarly journals Identification of structural defects in composite materials by the thermal imaging non-destructive testing method

2019 ◽  
Vol 298 ◽  
pp. 00119
Author(s):  
Andrey Kokurov ◽  
Igor Odintsev ◽  
Boris Chichigin ◽  
Dmitry Subbotin
Keyword(s):  
Composite Materials ◽  
Polymer Composites ◽  
Thermal Imaging ◽  
Structural Defects ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Testing Method ◽  
Non Destructive ◽  
Layered Polymer Composites

The article discusses the practical aspects of applying the thermal imaging non-destructive testing method of layered polymer composites. The specific purpose of the work is to demonstrate the possibilities of detecting in material and geometric identification of initial defects such as debonding.

THE METHODS OF NON-DESTRUCTIVE TESTING OF POSITIONING OF METALLIC DOWEL BARS IN JOINTS OF RIGID PAVEMENTS

2021 ◽  
Vol 2021 (24) ◽  
pp. 72-83
Author(s):  
Tetyana Tereshchenko ◽  
Keyword(s):  
Standard Method ◽  
Test Method ◽  
Magnetic Pulse ◽  
Concrete Pavements ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Road Pavement ◽  
General Part ◽  
Dowel Bar ◽  
Non Destructive

Introduction. In the world-wide practice on construction of rigid road pavements significant attention has been given to jointed plain concrete pavements (JPCP) with transverse joints strengthened by dowel bars. Performance of JPCP is sufficiently affected by right alignment and location of dowel bars thereby the methods of non-destructive testing of dowel bar positioning have been gain in great importance. This paper represents analytical review of methods of non-destructive testing of dowel bar alignment and location emphasizing an attention on standard method using magnetic pulse induction which is applicable to testing of metallic bar position in concrete pavements. General Part. In the general part of this paper, several main aspects of reviewed test method were analyzed: the classification of dowel bars misalignment and their impact on pavement performance; the comparison of implemented methods of non-destructive testing of dowel bar positioning; possibilities of method of magnetic impulse induction and an approach to analytical evaluation of transverse joints dowel bar misalignment using magnetic image tomography; the usage of results of testing of transverse joints dowel bar position to eliminate dowel bars misalignment; examples of predictive estimation of results of testing of transverse joints dowel bar position and their impact on performance of JPCP. The reviewed method of testing and test results estimation concerns practice on application of two levels of performance (e.g. acceptable level and rejectable level) to evaluate the performance of each individual dowel bar or each doweled transverse joint and also a section of rigid road pavement with several consecutive transverse joints with restricted performance. Conclusions. 1. World-wide implemented standard method of non-destructive testing of dowel bar alignment and location allows to detect and to eliminate dowel bars misalignment thus ensuring required load transfer efficiency and international roughness index of rigid road pavements. The estimation of road pavement sections with several consecutive joints considering each joint performance allows to ensure the designed service life of road pavement. 2. Standard method of non-destructive testing of dowel bar alignment and location for transverse joints of rigid road pavement using magnetic pulse induction developed by American Society for Testing and Materials assures high precision of measurement of metallic bar position in doweled bar of concrete pavement joints and enables to detect five types of dowel bar misalignment. 3. In connection with the intensification of issues on construction of rigid road pavements in Ukraine as well as the high importance of the considering test method, an important task should be the development and implementation of an appropriate national standard.

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