Evaluation of the Heat Resistance of the Fe-Cr-Al System Coatings

2021 ◽  
Vol 410 ◽  
pp. 525-530
Author(s):  
Vitaliy P. Kulevich ◽  
Oleg V. Slautin ◽  
Valentin O. Kharlamov
Keyword(s):  
Surface Layer ◽  
Chemical Composition ◽  
Corrosion Rate ◽  
Heat Resistance ◽  
Oxidation Rate ◽  
Chromium Content ◽  
Aluminum Melt ◽  
Heat Resistant ◽  
Aluminide Coatings

The influence of the chemical composition of aluminide coatings of the Fe-Cr-Al system on their heat resistance at 1100 °C was investigated. It is shown that the lowest oxidation rate is possessed by the coating obtained by aluminizing the Cr15Al5 alloy in the silumin melt, for which the depth of corrosion penetration after 500 h at 1100 °C did not exceed 2.5 μm. The depth of corrosion penetration after 500 h at 1100 °C in coatings with a higher chromium content (23 at.%) reaches 8.9 μm. A decrease in the content of chromium (up to 5 at.%) or aluminum (up to 10 at.%) in the surface layer is accompanied by a critical increase in the corrosion rate. The longest time of retention of heat-resistant properties at 1100 °C is possessed by the coating obtained by aluminizing the Cr23Al5 alloy in an aluminum melt.

scholarly journals THE INFLUENCE OF THE FE-CR-AL SYSTEM COATINGS CHEMICAL COMPOSITION ON THEIR HEAT RESISTANCE

2021 ◽  
pp. 7-12
Author(s):  
V. G. Shmorgun ◽  
A. I. Bogdanov ◽  
O. V. Slautin ◽  
V. P. Kulevich ◽  
S. A. Kuznecov
Keyword(s):  
Surface Layer ◽  
Chemical Composition ◽  
Corrosion Rate ◽  
Heat Resistance ◽  
Oxidation Rate ◽  
Aluminum Content ◽  
Chromium Content ◽  
Kinetics Of

The influence of the chemical composition of the Fe-Cr-Al system coatings on their heat resistance at 1100 °C was investigated. It is shown that the lowest oxidation rate is possessed by the coating obtained by aluminizing the Cr15Al5 alloy in the silumin melt, for which the depth of corrosion penetration after 500 h at 1100 °C was 2.5 μm. The depth of corrosion penetration in coating with a higher chromium content (23 at.%) reaches 8.9 μm. A decrease in the chromium content (up to 5 at.%) or aluminum (up to 10 at.%) in the surface layer is accompanied by a critical increase in the corrosion rate. Based on the kinetics of changes in the aluminum content in the surface layer, it was established that the coating obtained on the Cr23Al5 alloy has the highest heat resistance.

scholarly journals The influence of chemical composition on the heat resistance of casted structural steel

2021 ◽  
Vol 97 (1) ◽  
pp. 38-52
Author(s):  
Y.G. Aftandiliants ◽  
Keyword(s):  
Chemical Composition ◽  
Heat Resistance ◽  
Temperature Stress ◽  
Elevated Temperatures ◽  
Relative Elongation ◽  
Operating Time ◽  
Structural Steels ◽  
Operating Conditions ◽  
Structural Defects ◽  
Heat Resistant

The paper presents the results of the study of the influence of chemical composition, temperature, stress and operating time on the creep and durability of structural steels. It is shown that the efficiency of structural steels in conditions of elevated temperatures and loads depends on the chemical composition, stress level, operating time and temperature. The influence of alloying elements is associated with the inhibition of the process of weakening of heat-resistant steels due to the reduction of their diffusion mobility and intensity of redistribution between the ferrite and secondary phases, their coagulation and reduction of structural defects. Mathematical models of relative elongation and fracture time in the process of creep from operating conditions and degree of alloying of steel are constructed. It is established that the efficiency of heat-resistant structural steels depends on 61 - 64% of the degree of alloying, 18 - 21% - the value of external stress, 7 - 18% - temperature and 11% of operating time. It is shown that the coagulation of carbides and nitrides in steels doped with nitrogen and vanadium is slower than carbides in steels doped with molybdenum, which more effectively shifts the softening process of heat-resistant steel in the region of higher temperatures and time. Keywords: steel, heat resistance, chemical composition, temperature, stress, creep, durability.

Oxidation Rate of Advanced Heat-Resistant Steels for Ultra-Supercritical Boilers in Pressurized Superheated Steam

2001 ◽  
Vol 123 (3) ◽  
pp. 391-397 ◽  
Author(s):  
Yong-Sun Yi ◽  
Yutaka Watanabe ◽  
Tatsuo Kondo ◽  
Hiroshi Kimura ◽  
Minoru Sato
Keyword(s):  
Activation Energy ◽  
Chemical Composition ◽  
Oxidation Rate ◽  
Superheated Steam ◽  
Steam Pressure ◽  
Testing Temperature ◽  
Heat Resistant ◽  
Negative Effect ◽  
Major Factors ◽  
Heat Resistant Steels

Oxidation kinetics of recently developed ferritic heat-resistant steels, HCM12A, NF616, and HCM2S, were investigated in a superheated steam to evaluate the effects of chemical composition of the steels, testing temperature (560–700°C), steam pressure (1–10 MPa), and degrees of microstructural evolution by aging on oxidation. The contribution of alloyed Cr to oxidation resistance was pronounced above 600°C, while no material dependency was found at 600°C or lower. The apparent activation energy of the oxidation rate clearly changed at around 600°C for NF616 and HCM12A. In contrast, HCM2S showed single activation energy over the range of temperatures. Although temperature and chemical composition were the major factors, steam pressure also showed a clear negative effect on the oxidation rate in the lower temperature range, 570–600°C.

scholarly journals Molecular Physiological Characterization of a High Heat Resistant Spore Forming Bacillus subtilis Food Isolate

2021 ◽  
Vol 9 (3) ◽  
pp. 667
Author(s):  
Zhiwei Tu ◽  
Peter Setlow ◽  
Stanley Brul ◽  
Gertjan Kramer
Keyword(s):  
Bacillus Subtilis ◽  
Heat Resistance ◽  
Dipicolinic Acid ◽  
Laboratory Strain ◽  
High Heat ◽  
High Heat Resistance ◽  
Vegetative Cells ◽  
Heat Resistant ◽  
Food Isolate ◽  
Wet Heat

Bacterial endospores (spores) are among the most resistant living forms on earth. Spores of Bacillus subtilis A163 show extremely high resistance to wet heat compared to spores of laboratory strains. In this study, we found that spores of B. subtilis A163 were indeed very wet heat resistant and released dipicolinic acid (DPA) very slowly during heat treatment. We also determined the proteome of vegetative cells and spores of B. subtilis A163 and the differences in these proteomes from those of the laboratory strain PY79, spores of which are much less heat resistant. This proteomic characterization identified 2011 proteins in spores and 1901 proteins in vegetative cells of B. subtilis A163. Surprisingly, spore morphogenic protein SpoVM had no homologs in B. subtilis A163. Comparing protein expression between these two strains uncovered 108 proteins that were differentially present in spores and 93 proteins differentially present in cells. In addition, five of the seven proteins on an operon in strain A163, which is thought to be primarily responsible for this strain’s spores high heat resistance, were also identified. These findings reveal proteomic differences of the two strains exhibiting different resistance to heat and form a basis for further mechanistic analysis of the high heat resistance of B. subtilis A163 spores.

scholarly journals Properties of nickel-based superalloys of equiaxial crystallization

2021 ◽  
pp. 19-23
Author(s):  
O. Glotka ◽  
V. Olshanetskii
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Regression Models ◽  
Computational Prediction ◽  
Integrated Approach ◽  
Experimental Data Processing ◽  
Predictive Regression ◽  
Heat Resistant ◽  
First Time ◽  
Thermodynamic Processes

Purpose. The aim of the work is to obtain predictive regression models, with the help of which, it is possible to adequately calculate the mechanical properties of nickel-based superalloys of equiaxial crystallization, without carrying out preliminary experiments. Research methods. To find regularities and calculate  the latest CALPHAD method was chosen, and modeling of thermodynamic processes of phase crystallization was performed. Results. As a result of experimental data processing, the ratio of alloying elements Kg¢ was proposed for the first time, which can be used to assess the mechanical properties, taking into account the complex effect of the main alloy components. The regularities of the influence of the composition on the properties of heat-resistant nickel alloys of equiaxial crystallization are established. The analysis of the received dependences in comparison with practical results is carried out. The relations well correlated with heat resistance, mismatch and strength of alloys are obtained. Scientific novelty. It is shown that for multicomponent nickel systems it is possible with a high probability to predict a mismatch, which significantly affects the strength characteristics of alloys of this class. The regularities of the influence of the chemical composition on the structure and properties of alloys are established. A promising and effective direction in solving the problem of predicting the main characteristics of heat-resistant materials based on nickel is shown Practical value. On the basis of an integrated approach for multicomponent heat-resistant nickel-based alloys, new regression models have been obtained that make it possible to adequately predict the properties of the chemical composition of the alloy, which made it possible to solve the problem of computational prediction of properties from the chemical composition of the alloy. This allows not only to design new nickel-based alloys, but also to optimize the composition of existing brands.

scholarly journals INFLUENCE OF VACUUM ACTIVATED DIFFUSION CHROMING ON MECHANICAL PROPERTIES OF THE SURFACE OF STEEL 25X1MF

2020 ◽  
pp. 132-138
Author(s):  
S.G. Rudenkyi ◽  
V.I. Zmij ◽  
N.F. Kartzev ◽  
A.A. Korneev ◽  
A.V. Kunchenko ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Layer ◽  
Sodium Chloride ◽  
Abrasive Wear ◽  
Steel Surface ◽  
Chromium Content ◽  
Chromium Plating ◽  
Untreated Material

In the work, the surface of samples made of 25X1MF steel was saturated with chromium. For this, the method of vacuum activated diffusion chromium plating was used. In this process, sodium chloride was used as an activator. It was found that vacuum activated diffusion chromium plating of samples made of 25Kh1MF steel leads to the formation of a surface layer containing from 87 to 97 wt.% of this element. It was found that an increase in the temperature of the process and its duration leads to an increase in the chromium content on the surface of the samples. The tests showed that in the case of cavitations-erosion effects on the surface of chrome-plated samples of steel 25X1MF they have higher resistance. With abrasive wear, the resistance of the chrome-plated steel surface is 1.8 to 3 times higher compared to untreated material.

scholarly journals The laboratory tests of hybrid layers combining hardfacing and nitriding dedicated to increase the durability of forging tools in hot forging processes

2019 ◽  
Vol 91 (2) ◽  
Author(s):  
Paweł Widomski ◽  
Zbigniew Gronostajski ◽  
Marcin Kaszuba ◽  
Jagoda Kowalska ◽  
Mariusz Pawełczyk
Keyword(s):  
Surface Layer ◽  
Chemical Composition ◽  
Laboratory Tests ◽  
Hot Forging ◽  
Composition Analysis ◽  
Wear Resistant ◽  
Gas Nitriding ◽  
Use Wear ◽  
Different Types ◽  
Hybrid Layers

In response to the growing need to use wear-resistant layers that increase durability of tools in forging pro-cesses, hybrid layers have been proposed that combine hardfacing with nitriding treatment. This article presents the results of laboratory tests of surface wear-resistant layers made with a new hybrid technology Gas-Shielded Metal Arc surfacing (hardfacing) with ZeroFlow gas nitriding. Specimens made with hardfacing or nitriding were prepared and examined. Analysis covered the thorough microstructure study, EDX chemical composition analysis and microhardness analysis. In experiment, 3 different types of nitrided layers were proposed for alpha, gamma prim and epsilon nitrides in the surface layer. The results of metallographic research in the surface layer was presented. The analysis of chemical composition in the particular overlay welds was performed to determine the content of alloying elements in the particular overlay welds. The susceptibility to nitriding of used weld materials as well as the ability to form particular types of nitrides on selected welded substrates was also tested.

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