Structure and properties of high-strength stainless steel 1Kh15N4AM3

Voznesenskaya, N.M.; Izotov, V. I.; Ul'yanova, Nina; Popova, L. S.; Potak, Ya. M.

doi:10.1007/bf00663775

Cited by 7 publications

(2 citation statements)

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“…1). However, in the range of T temp ≈ (400-650) ° C, the amplitude of the EMAT signal decreases considerably; this is probably due to the liberation of finely dispersed M 2 X-type chromium carbonitride from martensite, which occurs during tempering above 400 ° C and the inverse α γ conversion at tempering temperatures of about 650 ° C [6]. Tempering at 650-700 ° C is accompanied by the decomposition of austenite; as a result, the amplitude of the EMAT signal increases.…”

Section: Resultsmentioning

confidence: 91%

Utilization of electromagnetic acoustic conversion to estimate microstress in steels

Горкунов

Задворкин

Solomein

2004

Russ J Nondestruct Test

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Results of studies on the influence of microstress on the parameters of electromagneticacoustic transduction (EMAT) in thermally treated and cold-worked steels are presented. It is shown that in thermally treated steels, except high-alloy corrosion-resistant austenite-martensite steel 1Kh15N5AM3Sh, the amplitude of the EMAT signal decreases linearly with an increase in the microstress. In this situation, the propagation velocity of normal elastic waves also decreases monotonously; this is also the case for 1Kh15N5AM3Sh steel. In pearlitic steel that is cold-worked by drawing, the dependences of the EMAT amplitude and the propagation velocity are linear only at the initial stage of deformation. After that, the parameters of the EMAT are affected most strongly by the phenomena that occur during the drawing: the turning of ferrite and carbide plates and the decrease in the dispersion angle of the axial crystallographic structure.Acoustic methods are of considerable interest for monitoring the strain-stress state of engine and machinery parts [1]. However, it is often problematic to use acoustic methods due to the necessity of providing contacts for the emitter and receiver of elastic waves with the object being studied. The electromagnetic-acoustic transduction (EMAT) method is most convenient for practical implementation; it combines the advantages of acoustic investigation methods with the possibility of contactless excitation and recording of elastic waves in an object being studied, provided that the object has a noticeable electric conductance or ferromagnetic properties [2]. Moreover, since acoustic waves are not "injected" from outside but are generated by the object itself with participation of its electric, magnetic, and elastic subsystems, the EMAT makes it possible to obtain additional information about the properties and condition of an object. In this study, we present results of studies on the relationship between EMAT characteristics and microstress in thermally treated and cold-worked steels of different grades. SPECIMENS AND EXPERIMENTAL PROCEDURESpecimens of the following steels have been studied: carbon steels 25, 70, and U8; low-alloy high-carbon steel ShKh15; two batches of high-alloy high-carbon steel R6M5 with different amounts of alloying elements; and low-carbon nitrogen-containing high-alloy steel 13Kh15N5AM3ShKh. The chemical compositions of the specimens are presented in the table. Different microstress levels in the specimens were obtained by varying the temperature of annealing after quenching (specimens of steels U8, ShKh15, R6M5, and 13Kh15N5AM3Sh) or by cold plastic deformation (specimens of patented steels 25 and 70).Specimens of steels U8 and ShKh15 were quenched from 850 ° C, those of steel 13Kh15N5AM3Sh were quenched from 1070 ° C, and those of steel R6M5 were quenched from 1250 ° C. Quenching was followed by annealing of the specimens. After the thermal treatment, the specimens were ground, and the effect of mechanical treatment on the internal stress was eliminated by electroly...

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Section: Resultsmentioning

confidence: 91%

Utilization of electromagnetic acoustic conversion to estimate microstress in steels

Горкунов

Задворкин

Solomein

2004

Russ J Nondestruct Test

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“…The drawbacks of these steels are related to the fact that variations in the chemical composition within the steel grade (e.g., in C and Ti) can substantially change the mechanical properties in the aged state. In addition, the mechanical properties substantially depend on the concentration of residual austenite, its stability, and alloying [1,2]. Thus, the technological process is developed depending on the purpose of the items that are made of these steels, as a result of which the concentration of residual austenite in their microstructure is regulated within a rather narrow range; thus, the optimal combination of mechanical properties is reached.…”

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confidence: 99%

A magnetic method for determining the concentration of residual austenite in maraging steels

Сташков

Somova

Sazhina

et al. 2011

Russ J Nondestruct Test

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810Maraging steels are widely used in shipbuilding, the aviation industry, and rocket production. Their advantages are associated with high strength combined with sufficient plasticity and high corrosion resis tance, good weldability, and the property of hot and cold plastic deformation. The drawbacks of these steels are related to the fact that variations in the chemical composition within the steel grade (e.g., in C and Ti) can substantially change the mechanical properties in the aged state. In addition, the mechanical properties substantially depend on the concentration of residual austenite, its stability, and alloying [1,2]. Thus, the technological process is developed depending on the purpose of the items that are made of these steels, as a result of which the concentration of residual austenite in their microstructure is regulated within a rather narrow range; thus, the optimal combination of mechanical properties is reached. As the result, it becomes necessary to develop nondestructive methods for evaluating the concentrations of resid ual austenite in the microstructures of ready made items.As shown by Apaev [3], the most suitable parameter for controlling the concentration of residual aus tenite is saturation magnetization. For example, specialists of the Institute of Metal Physics (IMP) devel oped a differential magnetic device that was designed for determining the concentration of residual austenite based on the measurements of the magnetization close to saturation in hardened and tempered items from ShKh15 steel [4]. However, when using this method for evaluating the concentration of residual austenite in martensite aging steels, they found a substantial spread in the obtained magnetization values [5].The saturation magnetization M s is known to be a characteristic that is sensitive to phase and chemical steel composition; thus, the obtained spread in the obtained saturation magnetization values can be explained by two factors. First, depending on the type of thermal treatment, the time of exposure at the specified temperatures, and heating and cooling rates, the martensite and the residual austenite in steels of such grade will differ in the degree of their alloying. For example, the concentration of nickel in residual austenite may substantially exceed that in the chemical composition of steel. Second, precipitation of par ticles of the second phase (intermetallic compounds, etc.) is accompanied by depletion of martensite with iron and nickel atoms, which should yield a decrease in magnetization. The testing reliability in this case can be increased by selecting a corresponding reference. This is a very complicated problem [3] since at the assigned concentration of residual austenite, the saturation magnetization of the martensite phase of the reference and tested objects should have similar values.Kifer [6] proposed using the internal demagnetization coefficient N i for studying the porosities of pow dered materials. Since the particles of residual paramagnetic austenite can be considered as pore...

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