Coercimetric Quality Testing of Steel Parts. Ural School of Coercimetry

NDT World ◽  
2015 ◽  
Vol 18 (4) ◽  
pp. 9-13
Author(s):  
Муриков ◽  
Sergey Murikov ◽  
Костин ◽  
Vladimir Kostin ◽  
Сташков ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Coercive Force ◽  
Hardened Layer ◽  
Scientific School ◽  
Deformation Degree ◽  
Practical Applications ◽  
Quality Testing ◽  
Hardened Layer Thickness ◽  
The Impact

The article shows the main areas of application coercimetric NDT method. The article presents historical information about the method founders who represents the Ural scientific school of magnetism. The main limitations of the method and practical applications of one-parameter and multiparameter coercimetric techniques are shown. Problems of magnetic quality inspection of quenched and tempered steels with different carbon contents and different degrees of alloying are considered. The possibility of monitoring the quality of steel products surface hardening with the use of external converters is demonstrated. Guidelines for external electromagnet size selection in dependence on a hardened layer thickness are presented. The brief analysis of the impact of current and residual stresses on the coercive force of steel products has been fulfilled. Problems of coercimetric inspection of stresses and steel plastic deformation degree are indicated; these problems are connected with varied behaviour of the coercive force under elastic extension and at high degrees of plastic deformation in the stage of pre-destruction. The originally developed technique for coercimetric quality control of forming rolls is presented. Information about modern coercimeters developed at the Institute of Metal Physics is provided.

scholarly journals Multiparameter method of surface hardening quality testing

2018 ◽  
Vol 224 ◽  
pp. 03016
Author(s):  
Vladimir Kostin ◽  
Olga Vasilenko ◽  
Alexander Byzov
Keyword(s):  
Coercive Force ◽  
Hysteresis Loop ◽  
Surface Hardening ◽  
Hardened Layer ◽  
Magnetic Characteristics ◽  
Software System ◽  
Residual Induction ◽  
Single Measurement ◽  
Measurement Results ◽  
Quality Testing

Measurements of the magnetic characteristics (coercive force, residual induction, induction of saturation) of objects that had different thicknesses of the hardened layer were made. The influence of an unstressed core on the measurement results, as well as the depth of the strengthened layer on the shape of the hysteresis loop, is investigated. The conclusion is made that it is possible to estimate the properties of a hardened layer by means of a single measurement with the help of the hardware-software system DIUS-1.15M

scholarly journals Selected Properties of the Surface Layer of C45 Steel Parts Subjected to Laser Cutting and Ball Burnishing

Materials ◽  
2020 ◽  
Vol 13 (15) ◽  
pp. 3429 ◽  
Author(s):  
Agnieszka Skoczylas ◽  
Kazimierz Zaleski
Keyword(s):  
Surface Layer ◽  
Residual Stresses ◽  
Laser Cutting ◽  
Experimental Studies ◽  
Hardened Layer ◽  
Ball Burnishing ◽  
Absolute Value ◽  
The Impact ◽  
Compressive Residual Stresses

In this article, we report the results of experimental studies on the impact of ball burnishing parameters on the roughness, microstructure and microhardness of the surface layer of laser-cut C45 steel parts. We also analysed the distribution of residual stresses generated in the surface layer of these parts. Laser-cut parts often require finishing to improve the quality of their surface. The tests performed in this study were aimed at assessing whether ball burnishing could be used as a finishing operation for parts of this type. Ball burnishing tests were performed on an FV-580a vertical machining centre using a mechanically controlled burnishing tool. The following parameters were varied during the ball burnishing tests: burnishing force Fn, path interval fw and the diameter of the burnishing ball dn. Ball burnishing of laser-cut C45 steel parts reduced the surface roughness parameters Sa and Sz by up to 60% in relation to the values obtained after laser cutting. Finish machining also led to the reorganization of the geometric structure of the surface, resulting in an increase in the absolute value of skewness Ssk. This was accompanied by an increment in microhardness (maximum microhardness increment was ΔHV = 95 HV0.05, and the thickness of the hardened layer was gh = 40 µm) and formation of compressive residual stresses in the surface layer.

scholarly journals Machine Learning for the Educational Sciences

2021 ◽  
Author(s):  
Sven Hilbert ◽  
Stefan Coors ◽  
Elisabeth Barbara Kraus ◽  
Bernd Bischl ◽  
Mario Frei ◽  
...  
Keyword(s):  
Machine Learning ◽  
Large Scale ◽  
Decisive Role ◽  
Quality Of Data ◽  
Practical Applications ◽  
Educational Sciences ◽  
Complex Relationships ◽  
The Impact ◽  
Analytical Approaches

Classical statistical methods are limited in the analysis of highdimensional datasets. Machine learning (ML) provides a powerful framework for prediction by using complex relationships, often encountered in modern data with a large number of variables, cases and potentially non-linear effects. ML has turned into one of the most influential analytical approaches of this millennium and has recently become popular in the behavioral and social sciences. The impact of ML methods on research and practical applications in the educational sciences is still limited, but continuously grows as larger and more complex datasets become available through massive open online courses (MOOCs) and large scale investigations.The educational sciences are at a crucial pivot point, because of the anticipated impact ML methods hold for the field. Here, we review the opportunities and challenges of ML for the educational sciences, show how a look at related disciplines can help learning from their experiences, and argue for a philosophical shift in model evaluation. We demonstrate how the overall quality of data analysis in educational research can benefit from these methods and show how ML can play a decisive role in the validation of empirical models. In this review, we (1) provide an overview of the types of data suitable for ML, (2) give practical advice for the application of ML methods, and (3) show how ML-based tools and applications can be used to enhance the quality of education. Additionally we provide practical R code with exemplary analyses, available at https: //osf.io/ntre9/?view only=d29ae7cf59d34e8293f4c6bbde3e4ab2.

Improvement of the Impact-Echo Method for the Higher Reliability in the Structural Integrity Assessment

2006 ◽  
Vol 321-323 ◽  
pp. 336-339 ◽  
Author(s):  
Mi Ra Cho ◽  
Ki Bong Kim ◽  
Sung Ho Joh ◽  
Tae Ho Kang
Keyword(s):  
Structural Integrity ◽  
Stress Wave Propagation ◽  
Layered Systems ◽  
Impact Echo ◽  
Practical Applications ◽  
Integrity Assessment ◽  
Excellent Method ◽  
The Impact ◽  
Impact Echo Method

The impact-echo method, which is to evaluate the integrity of concrete and masonry structures nondestructively, is an excellent method in practical applications, and provides a high quality of structural integrity assessment. However, in the case of multi-layered systems in which each layer has different stiffness, the impact-echo method may lack reliability in thickness evaluation, which demands improvement of the impact-echo method. This study was first dedicated to the understanding of stress-wave propagation in the impact-echo test, and secondly, the reliability of the impact-echo method was investigated through the numerical simulation of the impact-echo test. The investigation included the research on influencing factors such as stiffness contrast between layers and receiver location. Finally, the research in this paper led to the development of the phase-difference response (PDR) method, based on the frequency response between two receivers deployed in a line with an impact source.

Impact Deformation Model of Thin-Walled Shell Filled with Explosive under High Axial Shock Overload

2013 ◽  
Vol 455 ◽  
pp. 279-285
Author(s):  
Xiao Xia Sun ◽  
Wei Liu ◽  
Rui Qi Shen ◽  
Ying Hua Ye ◽  
Li Zhi Wu
Keyword(s):  
Plastic Deformation ◽  
Impact Damage ◽  
Plastic Deformation Zone ◽  
Deformation Model ◽  
Deformation Degree ◽  
Impact Stress ◽  
Gas Gun ◽  
Impact Deformation ◽  
Thin Walled ◽  
The Impact

The thin-walled shell axial impact deformation of one-leg electric detonator with different density charge was studied. The impact stress was analyzed, and on the basis of kinetic theory the impact deformation model was established for the thin-walled shell filled with explosive. The experiments were verified at 60 000g, 80 000g, 100 000g and 120 000g by gas gun. The results show that shell length decreases and the plastic deformation zone diameter increases after impact. Damage deformation degree decreases with increased shell strength, reduced shell and internal charging mass summation and reduced impact velocity square. The model calculated value agrees well with the test data. The deformation model can be used to predict overload damage deformation for such detonator.

scholarly journals Study on Automatic North-Seeking Key Technologies of Maglev Gyroscope

2013 ◽  
Vol 7 (1) ◽  
pp. 83-89 ◽  
Author(s):  
Shi Zhen ◽  
Yang Zhiqiang ◽  
Zhang Zhe
Keyword(s):  
Systematic Errors ◽  
Magnetic Suspension ◽  
Favorable Effect ◽  
Control Technology ◽  
Practical Applications ◽  
The North ◽  
Key Technologies ◽  
Magnetic Suspension System ◽  
The Impact

First, this paper proposes a static north-seeking mode based on the meridian seeking torque of gyroscope. We analyze the force situation and stability of the gyro magnetic suspension system in this mode and focus on the principle of torque balance feedback control technology. Two-position rotary control technology has been designed based on the sensitive state of the gyro rotor in four special north-seeking positions to reduce the impact of the systematic errors on the single position north-seeking. Later, we use the north-seeking data to simulate the real-time north-seeking process. Meanwhile, filter processing is used to improve the quality of the result. Finally, a comprehensive inspection is made to test the key technologies of the maglev gyro through the practice of an underground project. And it proves that these technologies have a favorable effect in practical applications.

Plastic Behavior of Laser Cladding Sample under Repeated-Impact Load

2010 ◽  
Vol 426-427 ◽  
pp. 294-298
Author(s):  
Shi Hong Shi ◽  
Ge Yan Fu
Keyword(s):  
Plastic Deformation ◽  
Impact Load ◽  
Base Material ◽  
Medium Carbon Steel ◽  
Plastic Behavior ◽  
Static Fatigue ◽  
Repeated Impact ◽  
Deformation Degree ◽  
Degree Of Deformation ◽  
The Impact

Low stress repeated impact experiments and test were carried out on medium carbon steel and stainless steel samples which is clad with high-strength Co-based or Ni-based alloy. The results showed that under low stress repeated impact load, which is much lower than the yield strength of material, plastic deformation will be occurred on the coating and part of its below base material. The average plastic deformation degree caused by each impact is increased at first, and then declined with the increase of impact times. Accumulated impact will lead to macroscopic plastic deformation and material hardening. The degree of deformation and the size of deformation area are related to the impact stress value and the material’s strength. The degree of deformation and hardening decline from the exterior to the interior, and only occur on the impact surface and a certain depth below, forming a ‘deformable area’. Based on our analysis, we consider that low stress repeated impact deformation is a kind of accumulative fatigue damage. The energy absorbed by material under repeated impact load, is larger than that absorbed at the same peak value of stress under static load or static fatigue load. Moreover, the energy absorbability is inversely proportional to the impact distance. Repeated impact may increase the movability of atom, reduce the critical shearing stress, that make the dislocation be initiated and increased easily.

scholarly journals The Impact of the COVID-19 Pandemic on the Quality of Educational Process: A Student Survey

2020 ◽  
Vol 17 (21) ◽  
pp. 7770 ◽  
Author(s):  
Maria-Crina Radu ◽  
Carol Schnakovszky ◽  
Eugen Herghelegiu ◽  
Vlad-Andrei Ciubotariu ◽  
Ion Cristea
Keyword(s):  
Educational Process ◽  
Assessment Process ◽  
Effective Teacher ◽  
Student Survey ◽  
Physical And Mental Health ◽  
Practical Applications ◽  
Teacher Student ◽  
The University ◽  
The Impact

The paper presents the results of a students’ survey carried out at “Vasile Alecsandri” University of Bacau, Romania, on the quality of educational process on online platforms in the context of the COVID-19 pandemic. The study was addressed to students from the Faculty of Engineering and the Faculty of Physical Education and Sports. The results of survey highlighted that most of students were satisfied with the measures taken by the university during the lockdown period and the way the teaching—learning-assessment process took place. However, some negative aspects were reported as: lack of an adequate infrastructure for some students, less effective teacher-student communication and interaction, impossibility of performing practical applications, lack of socialization, lack of learning motivation, less objective examination (e.g., possibility of cheating), possibility of physical and mental health degradation (e.g., too much time spent in front of screens, installation of a sedentary lifestyle). Consequently, for the new academic year, effective, and efficient measures must be implemented by the management of the university to remove, as much as possible, these negative issues and to improve the performance of online educational process.

The Impact of Mechanical Vibration on the Hardening of Metallic Surface

2012 ◽  
Vol 626 ◽  
pp. 90-94 ◽  
Author(s):  
Mohamed Amine Djema ◽  
Khaled Hamouda ◽  
Anatoly P. Babichev ◽  
Djamel Saidi ◽  
D. Halimi
Keyword(s):  
Plastic Deformation ◽  
Mechanical Vibration ◽  
Working Environment ◽  
Metallic Surface ◽  
Surface Fatigue ◽  
Relief Surface ◽  
Performance Functional ◽  
The Impact ◽  
Deformation Surface

One of functional parameters which have a big influence on the reliability of machine is the surface quality of mobile and immobile parts. The quality working ability of the surface in contact is depending of their surfaces strength. In this regard, we used vibro-mechanical treatment to increase the hardness of the contact surfaces which is considered as formed surface of plastic deformation. The formed plastic deformation surface is also a kind of micro relief surface, characterized by multitude closed and superimposed on each other traces of contact with the particles working environment cultivated surface. The quality of the surface resulting from the vibro-impact treatment, provide a sufficiently high wear parts. This paper presents experimental results of using the vibro-impact treatment on surface fatigue strength using samples of steels, aluminums and titans alloys. The objective of this study is to improve performance functional surfaces in contact by choosing optimal hardening parameters.

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