INVESTIGATION OF THE POSSIBILITIES OF ULTRASONIC TESTING OF CAST IRON WITH LAMELLAR GRAPHITE USING STANDARD NORMAL PROBE

2020 ◽  
pp. 4-18 ◽  
Author(s):  
V. N. Danilov ◽  
L. V. Voronkova
Keyword(s):  
Cast Iron ◽  
Ultrasonic Testing ◽  
Signal To Noise Ratio ◽  
Calculation Model ◽  
Normal Probe ◽  
Two Samples ◽  
Standard Normal ◽  
Lamellar Graphite ◽  
Comparison Of The Results ◽  
Physical Phenomena

Computer simulation of acoustic paths for medium – cast iron with lamellar graphite for standard normal probe of several types was carried out in order to study the effect of such medium on the characteristics of transmitted and received signals during ultrasonic testing. In the course of studies to calculate the attenuation coefficient of longitudinal waves in cast iron with lamellar graphite, due to their Rayleigh and phase scattering by graphite inclusions, the previously developed model was used. Comparison of the results of calculations of spectra and pulses of the recorded signals for two samples of cast iron with lamellar graphite confirmed the possibility of using the developed calculation model for a description of real physical phenomena adequate for the practice of ultrasonic testing. The ratio of the recorded signal and structural noise levels for different models of transducers, reflectors and characteristics of the controlled cast iron is estimated. Shown that increased attenuation of the longitudinal wave in cast iron in comparison with steel as a result of scattering by inclusions leads to higher level of this noise and can greatly reduce the signal-to-noise ratio in the detection of the reflected from the defect signals.

INVESTIGATION OF THE SPECIFICITY OF ULTRASONIC TESTING OF CAST IRON WITH GLOBULAR GRAPHITE USING LONGITUDINAL ELASTIC WAVES

2020 ◽  
pp. 6-25 ◽  
Author(s):  
V. N. Danilov ◽  
L. V. Voronkova
Keyword(s):  
Cast Iron ◽  
Ultrasonic Testing ◽  
Rayleigh Scattering ◽  
Frequency Spectra ◽  
Longitudinal Waves ◽  
Globular Graphite ◽  
Useful Signal ◽  
Two Samples ◽  
Standard Normal ◽  
Experimental Values

On the basis of the previously developed model for estimating the attenuation coefficient of elastic longitudinal waves in cast iron due to their Rayleigh scattering on graphite inclusions, the influence of such attenuation for cast iron with globular graphite on the characteristics of signals with frequency spectra of different widths depending on the nominal pulse frequencies, cast iron models and the distance traveled by the ultrasonic wave is studied. Computer modeling acoustic channel for environment – cast iron with globular graphite for standard normal probes of two types for studying influence of such environment on characteristics real transmitting and registered signals at the ultrasonic testing. Comparison of results of calculations of spectrums and pulses of registered bottom signals with their experimental values for two samples of cast iron with globular graphite has shown an opportunity of use of the applied settlement model for description of the actual physical phenomena quite adequate for practice. Influence of attenuation of longitudinal waves in cast iron with globular graphite on the directivity characteristic of their radiation is shown on model of cast iron and duration of a pulse. The estimation of the relation of levels of a registered signal and structural noise for various reflectors and characteristics of controllable cast iron has shown performance of recommendations by I. N. Ermolov on reliable detection of a useful signal on a background of noise for thickness, before established experimentally. Features of DGS-diagrams for cast iron with globular graphite, caused by higher, than in steel, attenuation of longitudinal waves and a little smaller speeds of their distribution are marked.

Morphology and mechanism of cavitation degradation of gray cast iron surfaces with lamellar graphite

2021 ◽  
Author(s):  
Eduard Riemschneider ◽  
Ilare Bordeasu ◽  
Ion Mitelea ◽  
Ion Dragos Utu ◽  
Corneliu Marius Crăciunescu
Keyword(s):  
Cast Iron ◽  
Gray Cast Iron ◽  
Gray Cast ◽  
Lamellar Graphite

Theory of Graphite Nucleation in Lamellar Graphite Cast Iron

2009 ◽  
Vol 3 (4) ◽  
pp. 39-47 ◽  
Author(s):  
A. Sommerfeld ◽  
B. Tonn
Keyword(s):  
Cast Iron ◽  
Graphite Cast Iron ◽  
Lamellar Graphite

Der Dauerbruch in perlitischem Gußeisen mit Lamellengraphit / Fatigue Fracture in Pearlitic Cast Iron with Lamellar Graphite

1975 ◽  
Vol 12 (11) ◽  
pp. 578-586
Author(s):  
Hermann Klingele ◽  
Bodo Böhlken ◽  
Vera Leidenroth
Keyword(s):  
Cast Iron ◽  
Fatigue Fracture ◽  
Lamellar Graphite

scholarly journals Modeling and Optimization for Fault Diagnosis of Electromechanical Systems Based on Zero Crossing Algorithm

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Qing Chen ◽  
Tao Liu ◽  
Xing Wu ◽  
Hua Li
Keyword(s):  
Fault Diagnosis ◽  
Feature Recognition ◽  
Signal To Noise Ratio ◽  
System Modeling ◽  
Industrial Process ◽  
Research Direction ◽  
Calculation Model ◽  
Electromechanical Systems ◽  
Zero Crossing ◽  
Characteristic Model

The demand of system security and reliability in the modern industrial process is ever-increasing, and fault diagnosis technology has always been a crucial research direction in the control field. Due to the complexity, nonlinearity, and coupling of multitudinous control systems, precise system modeling for fault diagnosis is attracting more attention. In this paper, we propose an improved method of electromechanical systems fault diagnosis based on zero-crossing (ZC) algorithm, which can present the calculation model of zero-crossing rate (ZCR) and optimize the parameters of ZC algorithm by establishing a criterion function model to improve the diagnosis accuracy and robustness of ZC characteristic model. The simulation validates the influence of different signal-to-noise ratio (SNR) on ZC feature recognition ability and indicates that the within-between distance model is effective to enhance the diagnose accuracy of ZC feature. Finally, the method is applied to the diagnosis of motor fault bearing, which confirms the necessity and effectiveness of the model improvement and parameter optimization and verifies the robustness to the load.

Investigation of Grey Cast Iron Microstructure Influence on its Heat Resistance

2018 ◽  
Vol 284 ◽  
pp. 332-337 ◽  
Author(s):  
Konstantin N. Vdovin ◽  
M.V. Shubina ◽  
I.G. Shubin
Keyword(s):  
Cast Iron ◽  
Heat Resistance ◽  
Thermal Cycling ◽  
Grey Cast Iron ◽  
Matrix Composition ◽  
Compact Graphite ◽  
Grey Cast ◽  
Lamellar Graphite ◽  
Materials Used ◽  
Graphite Inclusions

Grey cast iron is one of the most common engineering materials used to make castings which work in thermal cycling. Under thermal cycling conditions, heat resistance is an important operational property of grey cast iron, which depends to the greatest extent on its structure – size and shape of the graphite inclusions, as well as the metal matrix composition. In this paper, the heat resistance of unalloyed grey cast iron with lamellar and compact graphite distributed in perlitic and perlitic-ferritic metal matrices was determined. The tests were carried out at temperatures of 500 – 800 °C. The results of the studies showed an insignificant difference of perlitic and perlitic-ferritic grey cast iron with lamellar graphite heat resistance. The heat resistance of perlitic ferritic grey cast iron with compact graphite is 16 – 48 % higher than the heat resistance of perlitic ferritic grey cast iron with lamellar graphite. Thus, when the shape of the graphite inclusions changed from lamellar to compact, a significant increase in the heat resistance of unalloyed grey cast iron occurred.

A Calculation Model of Carbon Diffusion Coefficient in the Austenite for Spheroidal Graphite Cast Iron

2014 ◽  
Vol 789 ◽  
pp. 593-598
Author(s):  
Hong Liang Zheng ◽  
Lin Li ◽  
Xin Xin Yuan ◽  
Xue Lei Tian
Keyword(s):  
Diffusion Coefficient ◽  
Cast Iron ◽  
Carbon Content ◽  
Cooling Rate ◽  
Nodular Cast Iron ◽  
Carbon Diffusion ◽  
Calculation Model ◽  
Spheroidal Graphite ◽  
Atom Diffusion ◽  
Graphite Cast Iron

This paper presents the relationship between the carbon atom diffusion coefficient in the austenite and the temperature during the nodular cast iron solidification under different cooling rates or with different carbon contents. Pouring the wedge-shaped casting explores the influence of cooling rate on the diffusion coefficient. The other part explores the change of the diffusion coefficient with different carbon contents by water quenching to save the organization in the solidification. Results show that both the cooling rate and the carbon content can affect the diffusion coefficient, and it decreases as the cooling rate increases. More attempts were also done to correlate the diffusion coefficient with the temperature in different carbon content. It has been found that the diffusion coefficient decreases as the temperature increase.

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