scholarly journals Coercimeter for non-destructive control of solid alloys

2021 ◽  
Vol 2131 (5) ◽  
pp. 052042
Author(s):  
I K Tsybriy ◽  
N S Koval ◽  
I A Topolskaya

Abstract The widespread use of solid-alloy tools in modern engineering makes it necessary to ensure and maintain quality in the process of their production. The use of hard alloy plates of inadequate quality results in the instability of the mechanical processing and, as a consequence, the quality of the processed products in the batch is reduced. Heterogeneity of structure and properties is a significant disadvantage of products of cermet solid alloys as a product of powder metallurgy. They must therefore be subject to 100 per cent quality control. Today, various methods are used in order to control the physical and mechanical properties of products, such as hardness and microhardness of the surface and surface layer. Non-destructive control methods, one of which is a magnetic method based on measurement of the coercive force of an article, are of high priority and potential. A coercimeter instrument is proposed to implement this method. This research gives a description of the principle of its work, the functions performed by individual nodes, their electrical circuits and possibilities.

Materials ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 2930 ◽  
Author(s):  
Michał Landowski ◽  
Aleksandra Świerczyńska ◽  
Grzegorz Rogalski ◽  
Dariusz Fydrych

This study presents results of experimental tests on quality of dissimilar welded joints between 316L austenitic and 2304 lean duplex stainless steels, welded without ceramic backing. Fiber laser welded butt joints at a thickness of 8 mm were subjected to non-destructive testing (visual and penetrant), destructive testing (static tensile test, bending test, and microhardness measurements) and structure observations (macro- and microscopic examinations, SEM, element distribution characteristics, and ferrite content measurements). Non-destructive tests and metallographic examinations showed that the welded joints meet the acceptance criteria for B level in accordance with EN ISO 13919–1 standard. Also the results of the destructive tests confirmed the high quality of the joints: specimens were fractured in base material with lower strength—316L austenitic stainless steel and a 180° bending angle was obtained confirming the high plasticity of the joints. Microscopic examination, SEM and EDS analysis showed the distribution of alloying elements in joints. The microhardness of the autogenous weld metal was higher by about 20 HV0.2 than that of the lean duplex steel. Ferrite content in the root was about 37% higher than in the face of the weld. The Schaeffler phase diagram was used to predict the phase composition of the welded joints and sufficient compliance with the magnetic method was found. The presented procedure can be used for welding of 316L–2304 stainless steels dissimilar welded joints of 8 mm thickness without ceramic backing.


Author(s):  
I. A. Shibaev ◽  
V. A. Vinnikov ◽  
G. D. Stepanov

Geological engineering often uses geomechanical modeling aimed to enhance efficiency of mining or performance of structures. One of the input parameters for such models are the static elastic moduli of rocks. This article presents the studies into the physical and mechanical properties of rocks-limestone of non-metamorphic diagenesis. The precision measurements of Pand S-waves are carried out to an accuracy of 0.2% by laser ultrasonics. The static moduli of elasticity and the deformation characteristics of rocks are determined in the uniaxial compression tests by the standards of GOST 21153.2-84 and GOST 28985-91, respectively. The correlation dependence is found between the static and dynamic elasticity moduli in limestone samples. The found correlation allows drawing the conclusion that the static modulus of elasticity can be estimated in non-destructive tests, which largely simplifies preliminary diagnostics of samples in case of limited number of test core.


2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.


2020 ◽  
Vol 16 (3) ◽  
pp. 303-311
Author(s):  
Qi Huang ◽  
Chunsong Cheng ◽  
Lili Li ◽  
Daiyin Peng ◽  
Cun Zhang

Background: Scutellariae Radix (Huangqin) is commonly processed into 3 products for different clinical applications. However, a simple analytical method for quality control has rarely been reported to quickly estimate the degree of processing Huangqin or distinguish differently processed products or unqualified Huangqin products. Objective: To study a new strategy for quality control in the processing practice of Huangqin. Methods: Seven kinds of flavonoids that mainly exist in Huangqin were determined by HPLC-DAD. Chromatographic fingerprints were established to study the variation and discipline of the 3 processed products of Huangqin. PCA and OPLS-DA were used to classify differently processed products of Huangqin. Results: The results showed that baicalin and wogonoside were the main components in the crude and the alcohol Huangqin herb while baicalein and wogonin mainly existed in carbonized Huangqin. The results of mathematical statistics revealed that the processing techniques can make the quality of medicinal materials more uniform. Conclusion: This multivariate monitoring strategy is suitable for quality control in the processing of Huangqin.


Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1142
Author(s):  
Peter Pokorný ◽  
Štefan Václav ◽  
Jana Petru ◽  
Michaela Kritikos

Components produced by additive technology are implemented in various spheres of industry, such as automotive or aerospace. This manufacturing process can lead to making highly optimized parts. There is not enough information about the quality of the parts produced by additive technologies, especially those made from metal powder. The research in this article deals with the porosity of components produced by additive technologies. The components used for the research were manufactured by the selective laser melting (SLM) method. The shape of these components is the same as the shape used for the tensile test. The investigated parts were printed with orientation in two directions, Z and XZ with respect to the machine platform. The printing strategy was “stripe”. The material used for printing of the parts was SS 316L-0407. The printing parameters were laser power of 200 W, scanning speed of 650 mm/s, and the thickness of the layer was 50 µm. A non-destructive method was used for the components’ porosity evaluation. The scanning was performed by CT machine METROTOM 1500. The radiation parameters used for getting 3D scans were voltage 180 kV, current 900 µA, detector resolution 1024 × 1024 px, voxel size 119.43 µm, number of projections 1050, and integration time 2000 ms. This entire measurement process responds to the computer aided quality (CAQ) technology. VG studio MAX 3.0 software was used to evaluate the obtained data. The porosity of the parts with Z and XZ orientation was also evaluated for parts’ thicknesses of 1, 2, and 3 mm, respectively. It has been proven by this experimental investigation that the printing direction of the part in the additive manufacturing process under question affects its porosity.


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