Investigation of Structure and Properties of High-strength Bimetallic Materials Produced By Explosion Welding and Have Been Exploited in Arctic Climate

The paper presents the results of a comparative study of the structure, mechanical and magnetic properties of bimetallic materials obtained by explosion welding technology. The main layer of the studied bimetals is made of high-strength hull steel, and cladding – was performed by two corrosion-resistant steels with different degrees of austenite stability. According to the results of the shear test, it has been shown that explosion welding provides a solid one-piece connection with high values of the bond strength of the layers. Installed informative magnetic parameters could be used to develop non-destructive methods for assessing the changes occurring in the structure and phase composition of one of the bimetal layers under the action of plastic deformation.The work was partially supported by the RFBR, grant No 16-38-60027. The researchers used the equipment the “Plastometriya” collective use center

Eddy-current testing of fatigue degradation in additionally heat-treated gas powder laser clad NiCrBSi coating under contact fatigue loading

The paper studies the applicability of eddy-current technique to testing fatigue degradation in Ni-18.2Cr-3.3B-4.2Si coating, produced by gas powder laser cladding and subjected to additional high-temperature annealing at 1025 °C, under contact loading. It is demonstrated that eddy-current testing of fatigue degradation in Ni-18.2Cr-3.3B-4.2Si coating under contact loading after high-temperature annealing has certain limitations caused by the high brittleness of this coating. In this case, it is possible to test only a sharp increase in the sizes of contact damages, which occurs at 8×10 5 cycles under these loading conditions and results from the formation of a great number of peripheral ring cracks in the fracture zone; the eddy-current readings α decrease due to the increasing electrical resistivity of the coating. Testing can be performed by eddy-current measurements at high excitation frequencies of an eddy-current transducer (f=72-120 kHz), when the effect of the ferromagnetic steel base on the eddy-current readings α is minimum. © 2018 Author(s)

The effect of elastic deformation on the minor hysteresis loops of low carbon steel

The effect of elastic tensile deformations on the magnetic permeability of a structural low-carbon steel 20K (0.23 % C, 0.20 % Si, 0.46 % Mn) at various magnetic states was experimentally studied. To obtain these parameters, the measurements of minor hysteresis loops, which begin in the demagnetized state and in the remanent magnetization state, were carried out. The maximum tensile stress equal to 250 MPa that corresponds to 90 % of the conditional yield strength of studied steel. Stress dependences of the initial and reversible magnetic permeabilities as well as differential magnetic permeability along the descending branch of the minor hysteresis loop, which starts in the remanent magnetization state, are non-monotonic. They have extremums at σ = 50-70 MPa. However, stress dependences of the sums of those parameters are monotonic. The relative changes reach 25 % at tensile stresses of 250 MPa which make the promise of using the sums of magnetic permeabilities as parameters for assessing the magnitude of tensile stresses. © Published under licence by IOP Publishing Ltd.The research was funded by RFBR, project number 20-48-660035. The experiments were carried out with the use of the equipment of the Plastometriya collective use center affiliated to IES UB RAS

The influence of a combined strain-heat treatment on the features of electromagnetic testing of fatigue degradation of quenched constructional steel

The possibilities of the magnetic and eddy-current methods for testing fatigue degradation during low-cycle loading of quenched steel 50 (0.51% C) that was subjected to a combined strain-heat treatment according to an optimal regime that included friction treatment with subsequent tempering at T = 350 C, were investigated. It is shown that for steel that was subjected to a combined nanostructuring treatment, the accumulation of a plastic strain under "hard" cyclic loading can be tested using the coercimetric method and values of the residual magnetic induction on the major and minor magnetic-hysteresis loops, values of the maximum and initial magnetic permeabilities, and readings of an eddy-current instrument at a low excitation frequency of the eddy-current transducer. The appearance of surface fatigue cracks can be tested via eddy-current measurements at high frequencies, when the contribution of the crack formation in the hardened layer to the eddy-current characteristics is considerable. © 2013 Pleiades Publishing, Ltd

INVESTIGATION OF STRUCTURE AND PROPERTIES OF HIGH-STRENGTH BIMETALL MATERIALS PRODUCED BY EXPLOSION WELDING AND USED IN SEVERE ARCTIC CONDITIONS

This paper presets the results of the comparative investigation of structure, phase composition, mechanical and magnetic properties of the bimetal materials produced by means of explosion welding. The base metal is represented by high-strength hull steel and the cladding layer — by two corrosion-resistant steel with different stability of austenite. Investigations of structure and phase composition were carried out. According to the results of the shear tests, it has been shown that explosion welding provides a strength joint with high values of the bond strength of the layers. Informative magnetic parameters, allowing evaluating the changes occurring in individual layers of bimetal corrosion-resistant materials during plastic deformation were detected.В работе представлены результаты сравнительного исследования структуры, механических и магнитных свойств биметаллических материалов, полученных по технологии сварки взрывом. Основной слой — это корпусная высокопрочная сталь, плакирование выполнялось двумя коррозионностойкими сталями с разной степенью стабильности аустенита. Проведены исследования структуры и фазового состава. Результаты испытания на срез показали, что сварка взрывом позволяет получить прочное неразъемное соединение с высокими значениями прочности соединения слоев. Установлены информативные магнитные параметры, позволяющие оценивать изменения, происходящие в отдельных слоях биметаллических коррозионностойких материалов при пластическом деформировании.Работа выполнена при частичной поддержке гранта РФФИ 16-38-60027‑мол_а_дк. При выполнении работы использовано оборудование ЦКП «Пластометрия»

Eddy-current testing of fatigue degradation upon contact fatigue loading of gas powder laser clad NiCrBSi-Cr 3 C 2 composite coating

The possibilities of the eddy-current method for testing the fatigue degradation under contact loading of gas powder laser clad NiCrBSi-Cr 3 C 2 composite coating with 15 wt.% of Cr 3 C 2 additive have been investigated. It is shown that the eddy-current testing of the fatigue degradation under contact loading of the NiCrBSi-15%Cr 3 C 2 composite coating can be performed at high excitation frequencies 72-120 kHz of the eddy-current transducer. At that, the dependences of the eddy-current instrument readings on the number of loading cycles have both downward and upward branches, with the boundary between the branches being 3×10 5 cycles in the given loading conditions. This is caused, on the one hand, by cracking, and, on the other hand, by cohesive spalling and compaction of the composite coating, which affect oppositely the material resistivity and, correspondingly, the eddy-current instrument readings. The downward branch can be used to monitor the processes of crack formation and growth, the upward branch - to monitor the degree of cohesive spalling, while taking into account in the testing methodology an ambiguous character of the dependences of the eddy-current instrument readings on the number of loading cycles. © 2017 Author(s)

Structure and Properties of OCTG Pipe Cr–Mo Steel inTended for Operating in Sour Environment

При выполнении работы использовано оборудование ЦКП «Пластометрия».The paper presents the results of the study of microstructure, mechanical and corrosion properties of the economically alloyed Fe–Cr–Mo steel, designed for the production of OCTG to which the requirements are to provide increased strength and resistance to sulfide stress cracking (SSC) at the same time. The parameters that could be used for non-destructive testing methods developing to estimate the current state of structural elements during the operation conditions were established.Представлены результаты исследования структуры, механических, магнитных свойств экономнолегированной стали для нефтегазопромысловых труб, к которым предъявляются требования обеспечения повышенной прочности и стойкости к сульфидному растрескиванию под напряжением (СНР). Установлены параметры, которые в дальнейшем могут быть использованы при разработке методик неразрушающей диагностики состояния элементов конструкций из подобных материалов в процессе эксплуатации.Исследования выполнены в рамках работы по стипендии Президента РФ молодым ученым и аспирантам СП-150.2018.1

Magnetoelastic nonlinear metamaterials

We introduce the concept of magnetoelastic metamaterials with electromagnetic properties depending on elastic deformation. We predict a strong nonlinear and bistable response of such metamaterials caused by their structural reshaping in response to the applied electromagnetic field. In addition, we demonstrate experimentally the feasibility of the predicted effect.Comment: 4 pages, 5 figure