Effect of temperature on magnetic and impedance properties of Fe3BO6 of nanotubular structure with a bonded B2O3 surface layer

2018 ◽  
Vol 123 (9) ◽  
pp. 094101 ◽  
Author(s):  
Kalpana Kumari ◽  
S. Ram ◽  
R. K. Kotnala
Keyword(s):  
Surface Layer ◽  
Effect Of Temperature ◽  
Nanotubular Structure

scholarly journals Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools during Hot Die Forging

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 355
Author(s):  
Jakub Krawczyk ◽  
Paweł Widomski ◽  
Marcin Kaszuba
Keyword(s):  
Numerical Modeling ◽  
Surface Layer ◽  
Laboratory Tests ◽  
Complex Analysis ◽  
Nitrided Layer ◽  
Hot Forging ◽  
Thermal Softening ◽  
Effect Of Temperature ◽  
Destructive Effect ◽  
Forging Process

This article is devoted to the issues of thermal softening of materials in the surface layer of forging tools. The research covers numerical modeling of the forging process, laboratory tests of tempering of nitrided layers, and the analysis of tempering of the surface layer of tools in the actual forging process. Numerical modeling was supported by measuring the temperature inside the tools with a thermocouple inserted into the tool to measure the temperature as close to the surface as possible. The modeling results confirmed the possibility of tempering the die material. The results of laboratory tests made it possible to determine the influence of temperature on tempering at different surface layer depths. Numerical analysis and measurement of surface layer microhardness of tools revealed the destructive effect of temperature during forging on the tempering of the nitrided layer and on the material layers located deeper below the nitrided layer. The results have shown that in the hot forging processes carried out in accordance with the adopted technology, the surface layer of working tools is overheated locally to a temperature above 600 °C and tempering occurs. Moreover, overheating effects are visible, because the surface layer is tempered to a depth of 0.3 mm. Finally, such tempering processes lead to a decrease in the die hardness, which causes accelerated wear because of the abrasion and plastic deformation. The nitriding does not protect against the tempering phenomenon, but only delays the material softening process, because tempering occurs in the nitrided layer and in the layers deeper under the nitrided layer. Below the nitrided layer, tempering occurs relatively quickly and a soft layer is formed with a hardness below 400 HV.

Effect of temperature on the condition of niobium carbide surface layer during external friction

1974 ◽  
Vol 7 (4) ◽  
pp. 418-420
Author(s):  
M. S. Koval'chenko ◽  
Yu. G. Tkachenko ◽  
D. Z. Yurchenko ◽  
L. A. Klochkov
Keyword(s):  
Surface Layer ◽  
Niobium Carbide ◽  
External Friction ◽  
Effect Of Temperature

Study of Environmental Corrosion Behavior and Mechanism of the Carbon/Epoxy Composite

2007 ◽  
Vol 539-543 ◽  
pp. 913-918
Author(s):  
Xiao Fei Li ◽  
Qi Zhang ◽  
Jun Hua Xu
Keyword(s):  
Surface Layer ◽  
Composite Materials ◽  
Environmental Factors ◽  
Absorption Rate ◽  
Epoxy Composite ◽  
Advanced Technology ◽  
Advanced Materials ◽  
Effect Of Temperature ◽  
Corrosion Failure ◽  
Test Parameters

Polymer composite materials, as advanced materials have been widely used worldwide, especially in the advanced technology field, due to their outstanding properties. Nowadays, a growing attention has been paid to the environmental corrosion failure of composites. Since it is environment related corrosion, the test parameters selected were temperature, humidity and ultraviolet. Among all the environmental factors, the temperature, especially acts with humidity, is the most affective factor. In order to get detailed information, the weight gains of the samples tested were measured regularly during the test. By the comparison, it can be seen that the water absorption rate had been affected remarkably due to the salt existence or the temperature change. The observation of the sample microstructure showed that there were many holes on the surface, indicating that the surface of the samples was destroyed by the test, and that there were some interactions between the surface layer and the absorbed component. It is that only the effect of temperature and humidity was discussed in this paper, the effect of the rest environmental factors will be discussed in following paper.

scholarly journals Advanced Complex Analysis of the Thermal Softening of Nitrided Layers in Tools During Hot Die Forging

2020 ◽  
Author(s):  
Jakub Krawczyk ◽  
Paweł Widomski ◽  
Marcin Kaszuba
Keyword(s):  
Numerical Modeling ◽  
Surface Layer ◽  
Laboratory Tests ◽  
Complex Analysis ◽  
Nitrided Layer ◽  
Thermal Softening ◽  
Effect Of Temperature ◽  
Destructive Effect ◽  
Forging Process ◽  
Influence Of Temperature On

This article is devoted to the issues of thermal softening of materials in the surface layer of forging tools. The research covers numerical modeling of the forging process, laboratory tests of tempering of nitrided layers and the analysis of tempering of the surface layer of tools in the actual forging process. Numerical modeling was supported by measuring the temperature inside the tools with a thermocouple inserted into the tool to measure the temperature as close to the surface as possible. The modeling results confirmed the possibility of tempering the die material. The results of laboratory tests made it possible to determine the influence of temperature on tempering at different surface layer depths. Numerical analysis and measurement of surface layer microhardness of tools revealed the destructive effect of temperature during forging on the tempering of the nitrided layer and on the material layers located deeper below the nitrided layer.

The Effect of Temperature on Wear Mechanism of the AlCrN Coated Components

2016 ◽  
Vol 674 ◽  
pp. 233-238 ◽  
Author(s):  
Michał Michalak ◽  
Remigiusz Michalczewski ◽  
Edyta Osuch-Słomka ◽  
Demófilo Maldonado-Cortés ◽  
Marian Szczerek
Keyword(s):  
Wear Resistance ◽  
Surface Layer ◽  
High Temperature ◽  
Oxide Layer ◽  
Wear Mechanism ◽  
Room Temperature ◽  
Optical Microscope ◽  
Effect Of Temperature ◽  
High Wear Resistance ◽  
Protective Oxide

The aim of the paper was to investigate the temperature effect on the wear mechanism of AlCrN coated components. The coating was deposited by Physical Vapour Deposition process (PVD) on WC/Co substrate. Tribological tests were performed in sliding conditions using high temperature T‑21 tribotester, produced by ITeE-PIB Radom. The tests were performed in a ball-on-disc configuration (Si3N4 ceramic ball), under dry friction conditions at room temperature, 600°C and 750°C. An optical microscope, interferometer, and scanning electron microscope were used to analyse the worn surfaces. Following this study, it was found that wear resistance of the coating AlCrN tribosystem depended on the temperature. The biggest wear was reported at room temperature. At 600°C the intensity of wear of the coating was 4-fold lower, and at 750°C wear was 6-fold lower that at room temperature. High temperature wear resistance of AlCrN coating involves creating protective oxide layer. Performed analysis of structure the surface layer, showed a much higher content of oxygen in wear scar than outside. At high temperatures, friction additional intensified oxidation process thus the amount of oxygen in surface layer increased with temperature. Oxide layer, Al2O3 and Cr2O3 probably, created at high temperature was a barrier to further oxidation of the coating and had very high wear resistance at high temperature.

Electrochemical Properties of Ferrite and Cementite in Relation to Stress Corrosion of Mild Steels in Nitrate Solutions

CORROSION ◽  
1968 ◽  
Vol 24 (3) ◽  
pp. 66-69 ◽  
Author(s):  
J. A. S. GREEN ◽  
R. N. PARKINS
Keyword(s):  
Surface Layer ◽  
Electrochemical Properties ◽  
Stress Corrosion ◽  
Cathodic Polarization ◽  
Iron Electrode ◽  
Effect Of Temperature ◽  
Corrosion Reaction ◽  
Current Densities ◽  
Polarization Studies ◽  
Nitrate Solutions

Abstract Polarization studies were carried out both at an iron electrode and an iron electrode having a surface layer of cementite. Anodic and cathodic polarization curves were com-pared in nitrate and chloride solutions and the effect of temperature and the addition of acid was examined also. The Fe3C electrode was found to undergo relatively little cathodic polarization at low current densities and the cementite was thought to be acting as an efficient site for cathodic discharge during the corrosion reaction.

scholarly journals Factors Affecting the Wear Resistance of Forging Tools

2017 ◽  
Vol 62 (3) ◽  
pp. 1567-1576 ◽  
Author(s):  
M. Zwierzchowski
Keyword(s):  
Surface Layer ◽  
Working Conditions ◽  
Laboratory Tests ◽  
Effect Of Temperature ◽  
Laboratory Studies ◽  
Fem Modeling ◽  
Factors Affecting ◽  
Flat Surfaces ◽  
Mechanical Fatigue ◽  
Diffusion Layers

AbstractThe durability of forging tools is a function of many variables: tool heat treatment, surface quality, temperature, pressure, number of forgings, diffusion layers (nitriding) and many others. The objective of study was to analyze and compare the working conditions of forging tools. For the analysis of selected flat surfaces of tools. Analyzed forging dies subjected to normal use. Presented results of laboratory tests . The effect of temperature and time on the properties of the surface layer of forging tools. The results were compared with the literature data. This article shows the results of microhardness tests for forging dies which have forged the corresponding number of forgings. The results of laboratory studies on microhardness of hot working steel 1.2344 in the furnace at various temperatures and time are also presented. The working conditions of the forging tools are very complex. The most often described in the literature are: thermal fatigue, abrasive wear, mechanical fatigue and cracks. The article discusses the effects of increased temperature on the surface properties of forging tools. Forging dies were made of hot work tool steel 1.2344. FEM modeling of changes in the surface layer should take into account changes in tool hardness as a function of time (number of forgings).

The oxidation of Inconel alloy MA754 at low oxidation potential

1983 ◽  
Vol 41 ◽  
pp. 218-219
Author(s):  
D. N. Braski ◽  
P. D. Goodell ◽  
J. V. Cathcart ◽  
R. H. Kane
Keyword(s):  
Surface Layer ◽  
Oxidation Potential ◽  
Metal Interface ◽  
Elevated Temperature Strength ◽  
Surface Conditions ◽  
Inconel Alloy ◽  
Inco Alloy ◽  
Resistance To Oxidation ◽  
Oxide Particles ◽  
Cold Worked

It has been known for some time that the addition of small oxide particles to an 80 Ni—20 Cr alloy not only increases its elevated-temperature strength, but also markedly improves its resistance to oxidation. The mechanism by which the oxide dispersoid enhances the oxidation resistance is being studied collaboratively by ORNL and INCO Alloy Products Company.Initial experiments were performed using INCONEL alloy MA754, which is nominally: 78 Ni, 20 Cr, 0.05 C, 0.3 Al, 0.5 Ti, 1.0 Fe, and 0.6 Y2O3 (wt %).Small disks (3 mm diam × 0.38 mm thick) were cut from MA754 plate stock and prepared with two different surface conditions. The first was prepared by mechanically polishing one side of a disk through 0.5 μm diamond on a syntron polisher while the second used an additional sulfuric acid-methanol electropolishing treatment to remove the cold-worked surface layer. Disks having both surface treatments were oxidized in a radiantly heated furnace for 30 s at 1000°C. Three different environments were investigated: hydrogen with nominal dew points of 0°C, —25°C, and —55°C. The oxide particles and films were examined in TEM by using extraction replicas (carbon) and by backpolishing to the oxide/metal interface. The particles were analyzed by EDS and SAD.

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