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

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.

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.

Structure and Properties of the Surface Layer of a Wear-Resistant Coating on Martensitic Steel after Electron-Beam Processing

2017 ◽  
Vol 906 ◽  
pp. 101-106 ◽  
Author(s):  
Sergey V. Konovalov ◽  
V.E. Kormyshev ◽  
Yu.F. Ivanov ◽  
V.E. Gromov ◽  
I.A. Komissarova
Keyword(s):  
Surface Layer ◽  
Electron Beam ◽  
Layer Structure ◽  
Niobium Carbide ◽  
Young Modulus ◽  
Structural Elements ◽  
Cored Wire ◽  
Pulsed Electron Beam ◽  
Electron Beam Processing ◽  
Modified Surface

The paper reports electro-contact welding on Hardox 450 steel with С-V-Cr-Nb-W flux-cored wire. Supplementary irradiation by intense pulsed electron beam was carried out to improve mechanical properties. Micro-and nanohardness, Young modulus and tribological parameters of the modified surface were tested mechanically. It is pointed at the significant increase in the friction coefficient because the surface layer fractures and particles of the surfaced layer are involved in the process of friction. Using the methods of optical and scanning microscopy a great number of micro-pores were detected both on the irradiated surface and through the surfaced layer modified by intense pulsed electron beam. It is demonstrated that electron-beam processing of the deposited layer surface is the reason for occurrence of multi-layer structure. According to measurements it was determined that the modified (surface and transition) layers are 0.3 to 0.5 μm on overage. It was also found out that irradiation of the surfaced metal leads to significant refining of structural elements because of ultrahigh speeds of crystallization and further cooling down of the modified layer. The phase composition of the surfaced metal modified by pulsed electron beam is explored. Niobium carbide (NbC) is reported to form in the surface 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.

Calculation of the Amount of the Reduction Required for the Formation of Compound Layers during Cold Rolling of Bimetals

2016 ◽  
Vol 870 ◽  
pp. 328-333 ◽  
Author(s):  
A.V. Shaparev ◽  
I. Savin
Keyword(s):  
Plastic Deformation ◽  
Surface Layer ◽  
Cold Rolling ◽  
External Friction ◽  
Geometric Shapes ◽  
Strip Tension

Calculated values of joint plastic deformation for forming a connection layer of the bimetal during cold rolling. Deflection of the primary setting of the bimetal layers depends on the thickness and sizes of destruction blocks, the ratio of the geometric shapes of the blocks of the surface layer destruction, the external friction during rolling, the strip tension, the diameter of the rolls, the thickness of the bimetallic billet.

Sign in / Sign up

Export Citation Format

Share Document