Complex metallophysical studies of structural steels after two-component diffusion hardening based on boron

2021 ◽  
pp. 18-24
Author(s):  
V.M. Roshchupkin ◽  
Yu.V. Skripkina ◽  
V.N. Gadalov ◽  
O.M. Gubanov
Keyword(s):  
Brittle Failure ◽  
Structural Steels ◽  
Dynamic Effects ◽  
English Version ◽  
Surface Layers ◽  
Powder Mixtures ◽  
Wear Process ◽  
Two Component ◽  
Structure Phase ◽  
Boride Phases

The studies of the structure, phase composition and microhardness of 45; 40X13 and (25...30) CMT steels during hardening in mixtures containing boron, boron and silicon, as well as boron, silicon and aluminum, are presented. Boration was carried out at a temperature of 890°C for 3 hours. The results of the study show that as a result of boration, the layer thickness is greater than in the case of borosiliconizing and boro-alumino-siliconizing, however, the needles of the boride phases are sharper. By obtaining diffusive layers that differ in structure with different phase ratios FeB, Fe2 B, Fe3 Si, it is possible to significantly influence the resistance to brittle failure of the surface layers of parts that are operated under real conditions in friction pairs under periodic or constant shock effects. So, if the wear process proceeds without ever manifesting dynamic effects, then it is possible to recommend the use of the boration process – both for small-sized parts with CTR in powder mixtures using unpressurized containers, and large-sized parts - in coatings that are applied only to the wearing surfaces of the parts. If the wear occurs under conditions of a relatively low level of periodically manifested shock effects, it is possible to use the borosiliconizing process at (800...900)°C. English version of the article is available at URL: https://panor.ru/articles/complex-metal-physical-studies-of-structural-steels-after-twocomponent-boron-based-diffusion-hardening/69778.html

scholarly journals CHANGES IN FATIGUE RESISTANCE OF STRUCTURAL STEELS AT DIFFERENT LOADING SPECTRA

2019 ◽  
Vol 62 (10) ◽  
pp. 796-802
Author(s):  
V. V. Myl’nikov ◽  
D. I. Shetulov ◽  
O. B. Kondrashkin ◽  
E. A. Chernyshov ◽  
A. I. Pronin
Keyword(s):  
Fatigue Resistance ◽  
Resistance Index ◽  
Fatigue Curve ◽  
Cyclic Strength ◽  
Structural Steels ◽  
Experimental Results ◽  
Cyclic Behavior ◽  
Material Surface ◽  
Loading Frequency ◽  
Surface Layers

Fatigue strength of widely used engineering structural steels was  studied at various frequencies of loading according to the scheme of  cantilever bending of the rotating cylindrical samples. Fatigue resistance index is tangent of angle of inclination of fatigue curve to axis  of longevity. It is established that 40 and 45 steels belong to the group  of materials in which decrease in frequency of loading leads to cyclic  softening and decrease in fatigue resistance, which is numerically expressed by increasing slope of fatigue curve. Tests of the samples made  of 40X steel had shown that increase in frequency of loading cycles  leads to a noticeable decrease in slope of fatigue curve parameter, i.e.  to an increase in fatigue resistance. Decrease in fatigue resistance parameter is associated with an increase in hardening of material of the  samples (parts) surface layers which reduces fatigue damage to the  surface itself. Dependence of the fatigue curve slope tangent on surface damage at changing loading cycles frequency is shown and it is  stated that, regardless of frequency, damage of material surface layers  increases along the slope of fatigue curve. For each of these groups  mathematical relations are defined. The correlation coefficient providing degree of convergence of experimental results with the constructed fatigue curve was adopted as a criterion of cyclic behavior stability  of steels. It is revealed that increase in behavior stability of 40X steel  is observed with increase in cyclic deformation rate. Tests of 45  steel  have shown that decrease in cyclic strength with increase in loading  frequency does not affect fatigue stability of material. Increased dispersion of experimental results was observed in 40 steel at low loading  frequency, despite the high values of cyclic strength at given loading  frequency. On the basis of conducted experiments, dynamics of behavior of real machine parts and structures subjected to cyclic loads  operating was determined in the studied loading spectrum.

THE DENSITY OF PACKING OF TWO-COMPONENT POWDER MIXTURES

1965 ◽  
Vol 8 (15) ◽  
pp. 20-37 ◽  
Author(s):  
H. E. ROSE ◽  
D. J. ROBINSON
Keyword(s):  
Powder Mixtures ◽  
Two Component

scholarly journals Production and application of low-energy, high-current electron beams

2003 ◽  
Vol 21 (2) ◽  
pp. 157-174 ◽  
Author(s):  
G.E. OZUR ◽  
D.I. PROSKUROVSKY ◽  
V.P. ROTSHTEIN ◽  
A.B. MARKOV
Keyword(s):  
Electron Beams ◽  
Low Energy ◽  
Nonstationary Temperature ◽  
High Current ◽  
Surface Layers ◽  
Explosive Emission ◽  
Energy Density Distribution ◽  
Structure Phase ◽  
Current Electron ◽  
High Current Electron

This article reviews experiments on the production of low-energy, high-current electron beams (LEHCEB) and their use for surface modification of materials. It is shown that electron guns with a plasma anode and an explosive emission cathode are most promising for the production of this type of beams. The problems related to the initiation of explosive emission and the production and transportation of LEHCEBs in plasma-filled diodes are considered. It has been shown that if the rise time of the accelerating voltage is comparable to or shorter than the time it takes for an ion to fly through the space charge layer, the electric field strength at the cathode and the electron current density in the layer are increased. Experimentally, it has been established that the current of the beam transported in the plasma channel is 1–2 orders of magnitude greater than the critical Pierce current and several times greater than the chaotic current of the anode plasma electrons. Methods for improving the uniformity of the energy density distribution over the beam cross section are described. The nonstationary temperature and stress fields formed in metal targets have been calculated. The features of the structure-phase transformations in the surface layers of materials irradiated with LEHCEBs have been considered. It has been demonstrated that in the surface layers quenched from the liquid state, nonequilibrium structure-phase states are formed.

scholarly journals Application of a Dy3Co0.6Cu0.4Hx Addition for Controlling the Microstructure and Magnetic Properties of Sintered Nd-Fe-B Magnets

Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4235 ◽  
Author(s):  
Katerina Skotnicova ◽  
Pavel A. Prokofev ◽  
Natalia B. Kolchugina ◽  
Gennady S. Burkhanov ◽  
Alexander A. Lukin ◽  
...  
Keyword(s):  
New Technologies ◽  
Rare Earth Metals ◽  
Heavy Rare Earth ◽  
Powder Mixtures ◽  
The Core ◽  
Two Component ◽  
Blending Process ◽  
Hysteretic Properties ◽  
Microstructure And Magnetic Properties

The focus of new technologies on the formation of inhomogeneous distributions of heavy rare-earth metals (REMs) in hard magnetic Nd–Fe–B materials is of scientific importance to increase their functional properties, along with preserving existing sources of heavy REMs. This paper focused on the coercivity enhancement of Nd2Fe14B-based magnets by optimizing the microstructure, which includes the processes of grain boundary structuring via the application of a Dy3Co0.6Cu0.4Hx alloy added to the initial Nd–Fe–B-based powder mixtures in the course of their mechanical activation. We have studied the role of alloying elements in the formation of phase composition, microstructure, the fine structure of grains, and the hysteretic properties of hard magnetic Nd(R)2Fe14B-based materials. It was shown that the Dy introduction via the two-component blending process (the hydrogenated Dy3Co0.6Cu0.4 compound is added to a powder mixture) resulted in the formation of the core-shell structure of 2–14–1 phase grains. The efficient improvement of the coercivity of Nd(RE)–Fe–B magnets, with a slight sacrifice of remanence, was demonstrated.

Structure–phase state of the surface layers in rails subjected to differential hardening

2015 ◽  
Vol 2015 (13) ◽  
pp. 1094-1097
Author(s):  
V. E. Gromov ◽  
A. M. Glezer ◽  
K. V. Morozov ◽  
Yu. F. Ivanov ◽  
K. V. Volkov
Keyword(s):  
Phase State ◽  
Surface Layers ◽  
Structure Phase

Plasticity evaluation of structural steels by uniform tensile stage parameters

2021 ◽  
pp. 24-31
Author(s):  
Vladislav Khotinov ◽  
◽  
Vladimir Farber ◽  
Keyword(s):  
Mechanical Properties ◽  
Power Law ◽  
Phase State ◽  
Analytical Description ◽  
Structural Steels ◽  
Initial Structure ◽  
Strengthening Mechanisms ◽  
Wide Range ◽  
Structure Phase

Mechanical properties of specimens of Armco-Fe and a wide range of structural steels in various structural conditions have been studied. It has been found out that the use of different strengthening mechanisms leads to a decrease in plasticity parameters with different intensity at the uniform and localized tensile stages. Analysis of the tensile engineering and true curves showed that splitting a uniform stage into linear and power-law periods gave the best analytical description of experimental tensile curves with R2 = 0.99. The plasticity parameters on linear and power-law periods that are sensitive to changing the initial structure-phase state of the studied steels are proposed.

Structure and properties of titanium surface layers after electron beam alloying with powder mixtures containing carbon

2015 ◽  
Vol 355 ◽  
pp. 320-326 ◽  
Author(s):  
O.G. Lenivtseva ◽  
I.A. Bataev ◽  
M.G. Golkovskii ◽  
A.A. Bataev ◽  
V.V. Samoilenko ◽  
...  
Keyword(s):  
Electron Beam ◽  
Titanium Surface ◽  
Structure And Properties ◽  
Surface Layers ◽  
Powder Mixtures
Sign in / Sign up

Export Citation Format

Share Document