scholarly journals Verification of the working life of a ploughshare renovated by surfacing and remelting in the operation

2014 ◽  
Vol 60 (Special Issue) ◽  
pp. S98-S103 ◽  
Author(s):  
I. Kováč ◽  
N. Vanko ◽  
M. Vysočanská
Keyword(s):  
High Hardness ◽  
Working Life ◽  
Operating Conditions ◽  
Inert Gas ◽  
Material Surface ◽  
Chemical Heat Treatment ◽  
Functional Area ◽  
Chemical Heat ◽  
Coated Electrodes ◽  
Suitable Environment

The most common way of renovation of the working parts of agricultural machinery is surfacing by hardfacing coated electrodes and piped hardfacing wires. Another way to prolong the working life of the machinery is the chemical heat treatment of the material surface by nitriding. By nitriding, high hardness is obtained of the surface affected by a suitable environment and by raised temperature. This paper deals with the possibilities of increasing the lifetime of the functional area of a ploughshare by the surfacing piped wire and hardfacing electrodes and reshaping the surface layer in an argon and nitrogen environment by using a welding rectifier and the Tungsten Inert GAS method, and by validation of these methods of renovation in operating conditions.

Increase of Tool Steel Durability in Abrasion Wear Conditions

2014 ◽  
Vol 611 ◽  
pp. 424-429 ◽  
Author(s):  
Martin Orečný ◽  
Peter Frankovský ◽  
Petra Lacková ◽  
Marián Buršák
Keyword(s):  
Heat Treatment ◽  
Wear Resistance ◽  
Abrasive Wear ◽  
Tool Steel ◽  
High Hardness ◽  
Chemical Heat Treatment ◽  
Chemical Heat ◽  
Saw Dust ◽  
Abrasion Wear ◽  
Materials Used

The article proposes possible increase of durability of tool steel X210Cr12 as regards working conditions under consideration of abrasive wear. From such steel tools are made for pressing wooden briquettes and saw dust waste. In practical environment a condition is held that if a material should work in abrasive wear conditions, it should have high hardness and should contain carbides in the structure. The proposed paper deals with the heat and chemical-heat treatment (nitriding) of tool steel which is working in hard abrasive wear conditions. From the obtained results it is not easy to conclude a definitive conclusion or to set the boundaries between the factors that are responsible for wear resistance. It is shown that the chemical-heat treatment can in the last step of the heat treatment lead to an increase or even to a decrease in the abrasive wear resistance of the material. The aim of the paper is to set a proper heat treatment of materials used for pressing in abrasion wear conditions.

Microstructural Effects between AHSS Dissimilar Joints Using MIG and TIG Welding Process

2015 ◽  
Vol 1766 ◽  
pp. 29-35 ◽  
Author(s):  
G.Y. Pérez Medina ◽  
M. Padovani ◽  
M. Merlin ◽  
A.F. Miranda Pérez ◽  
F.A. Reyes Valdés
Keyword(s):  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
High Hardness ◽  
Inert Gas ◽  
Mechanical Degradation ◽  
Low Alloy Steels ◽  
Dissimilar Joints ◽  
Lap Shear ◽  
Welding Processes

ABSTRACTGas tungsten arc welding-tungsten inert gas (GTAW-TIG) is focused in literature as an alternative choice for joining high strength low alloy steels; this study is performed to compare the differences between gas metal arc welding-metal inert gas (GMAW-MIG) and GTAW welding processes. The aim of this study is to characterize microstructure of dissimilar transformation induced plasticity steels (TRIP) and martensitic welded joints by GMAW and GTAW welding processes. It was found that GMAW process lead to relatively high hardness in the HAZ of TRIP steel, indicating that the resultant microstructure was martensite. In the fusion zone (FZ), a mixture of phases consisting of bainite, ferrite and small areas of martensite were present. Similar phase’s mixtures were found in FZ of GTAW process. The presence of these mixtures of phases did not result in mechanical degradation when the GTAW samples were tested in lap shear tensile testing as the fracture occurred in the heat affected zone. In order to achieve light weight these result are benefits which is applied an autogenous process, where it was shown that without additional weight the out coming welding resulted in a high quality bead with homogeneous mechanical properties and a ductile morphology on the fracture surface. Scanning electron microscopy (SEM) was employed to obtain information about the specimens that provided evidence of ductile morphology.

scholarly journals Carbonitration of a Tool for Pressing Stainless Steel Pipes

2020 ◽  
Vol 7 (2) ◽  
pp. C17-C21
Author(s):  
I. V. Ivanov ◽  
M. V. Mohylenets ◽  
K. A. Dumenko ◽  
L. Kryvchyk ◽  
T. S. Khokhlova ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Thermal Treatment ◽  
Heat Resistance ◽  
Alkali Metals ◽  
Matrix Ring ◽  
High Hardness ◽  
Operating Conditions ◽  
Matrix Rings ◽  
Conventional Heat Treatment ◽  
The Stability

To upgrade the operational stability of the tool at LLC “Karbaz”, Sumy, Ukraine, carbonation of tools and samples for research in melts of salts of cyanates and carbonates of alkali metals at 570–580 °C was carried out to obtain a layer thickness of 0.15–0.25 mm and a hardness of 1000–1150 НV. Tests of the tool in real operating conditions were carried out at the press station at LLC “VO Oscar”, Dnipro, Ukraine. The purpose of the test is to evaluate the feasibility of carbonitriding of thermo-strengthened matrix rings and needle-mandrels to improve their stability, hardness, heat resistance, and endurance. If the stability of matrix rings after conventional heat setting varies around 4–6 presses, the rings additionally subjected to chemical-thermal treatment (carbonitration) demonstrated the stability of 7–9 presses due to higher hardness, heat resistance, the formation of a special structure on the surface due to carbonitration in salt melts cyanates and carbonates. Nitrogen and carbon present in the carbonitrided layer slowed down the processes of transformation of solid solutions and coagulation of carbonitride phases. The high hardness of the carbonitrified layer is maintained up to temperatures above 650 °C. If the stability of the needle-mandrels after conventional heat treatment varies between 50–80 presses, the needles, additionally subjected to chemical-thermal treatment (carbonitration) showed the stability of 100–130 presses due to higher hardness, wear resistance, heat resistance, the formation of a special surface structure due to carbonitration in melts of salts of cyanates and carbonates. Keywords: needle-mandrel, matrix ring, pressing, heat treatment, carbonitration.

Comparative Analysis of Novikov and Involute Gearing in the ANSYS Workbench Software Package

2021 ◽  
pp. 16-21
Author(s):  
S.I. Karatushin ◽  
D.A. Khramova ◽  
N.A. Bildyuk
Keyword(s):  
Heat Treatment ◽  
Comparative Analysis ◽  
Software Package ◽  
Strain State ◽  
Gear Ratio ◽  
Geometric Parameters ◽  
Chemical Heat Treatment ◽  
Chemical Heat ◽  
Additional Hardening ◽  
Ansys Workbench

The paper introduces the results of studying the stress-strain state of the Novikov gearing in comparison with the involute gearing, similar in geometric parameters. In both versions, the wheel and gear are selected in size and gear ratio in accordance with the most common recommendations without additional hardening by chemical heat treatment. The zone of multiple contact of mated profiles is analyzed: changes in the geometry of contacts, pressure in the contact and stresses in various phases of gearing.

Chemical-heat treatment influence on thermal stability of microstructure, mechanical properties and fracture features of V-Cr-Ta-Zr alloy

2021 ◽  
pp. 36-42
Author(s):  
I.V. Smirnov ◽  
◽  
K.V. Grinyaev ◽  
A.N. Tyumentsev ◽  
A.D. Korotaev ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Thermal Stability ◽  
Structural Phase ◽  
Strength Properties ◽  
Chemical Heat Treatment ◽  
Chemical Heat ◽  
High Level ◽  
Fracture Features ◽  
Zr Alloy

A study of the features of structural-phase state, thermal stability, mechanical properties characteristics and fracture features of V-Cr-Ta-Zr alloy after chemical-heat treatment by the method of nonequilibrium internal oxidation has been carried out. It has been established that, in contrast to chemical-heat treatment in a defect state, the effect of oxygen when introduced into a material with a stabilized structure is observed only at high concentrations. At such oxygen concentrations, which ensure the maximum binding of Zr into particles based on ZrO2, the alloy under study demonstrates a high level of thermal stability and strength properties. These effects are associated with the implementation of disperse strengthening according to the Orowan mechanism by nanosized ZrO2 particles characterized by high thermal stability. The concentration and nature of the distribution of oxygen predetermine the spatial distribution of nanosized ZrO2 particles formed during chemical-heat treatment, which manifests itself in fracture features of the material at different temperatures.

Residual Compressive Stresses and Defects of Layers Hardened by Chemical Heat Treatment

Metallurgist ◽  
2013 ◽  
Vol 57 (7-8) ◽  
pp. 629-632
Author(s):  
I. P. Banas ◽  
L. V. Morozova ◽  
E. N. Korobova ◽  
O. V. Sedov
Keyword(s):  
Heat Treatment ◽  
Chemical Heat Treatment ◽  
Chemical Heat ◽  
Compressive Stresses

scholarly journals Laser alloying of bearing steel with boron and self-lubricating addition

2016 ◽  
Vol 36 (1) ◽  
pp. 7-11 ◽  
Author(s):  
Mateusz Kotkowiak ◽  
Adam Piasecki ◽  
Michał Kulka
Keyword(s):  
Wear Resistance ◽  
Calcium Fluoride ◽  
High Hardness ◽  
Bearing Steel ◽  
Operating Conditions ◽  
High Wear Resistance ◽  
Laser Alloying ◽  
Amorphous Boron ◽  
Rolling Bearings ◽  
Borided Layer

Abstract 100CrMnSi6-4 bearing steel has been widely used for many applications, e.g. rolling bearings which work in difficult operating conditions. Therefore, this steel has to be characterized by special properties such as high wear resistance and high hardness. In this study laser-boriding was applied to improve these properties. Laser alloying was conducted as the two step process with two different types of alloying material: amorphous boron only and amorphous boron with addition of calcium fluoride CaF2. At first, the surface was coated with paste including alloying material. Second step of the process consisted in laser re-melting. The surface of sample, coated with the paste, was irradiated by the laser beam. In this study, TRUMPF TLF 2600 Turbo CO2 laser was used. The microstructure, microhardness and wear resistance of both laser-borided layer and laser-borided layer with the addition of calcium fluoride were investigated. The layer, alloyed with boron and CaF2, was characterized by higher wear resistance than the layer after laser boriding only.

Application of In Situ 3D Computed Tomography during PVT Growth of 4H-SiC for the Study of Source Material Consumption under Varying Growth Conditions

2016 ◽  
Vol 858 ◽  
pp. 49-52 ◽  
Author(s):  
P.J. Wellmann ◽  
Lars Fahlbusch ◽  
Michael Salamon ◽  
Norman Uhlmann
Keyword(s):  
Growth Parameters ◽  
Growth Conditions ◽  
Source Material ◽  
Gas Pressure ◽  
Inert Gas ◽  
Material Surface ◽  
Growth Interface ◽  
Axial Temperature ◽  
The Stability

2D and 3D in-situ X-ray visualization was applied to study the behavior of the SiC source material during PVT growth under various growth conditions. Experiments were carried out in two growth chambers for the growth of 3 inch and 4 inch crystals. Growth parameters were varied in the gas room in terms of axial temperature and inert gas pressure. The study addresses the stability of the SiC source material surface. It is shown that a higher inert gas pressure (e.g. 25 mbar) inhibits an unintentional upward evolution of the SiC feedstock that interferes with the crystal growth interface. The latter is related to a suppression of a pronounced recrystallization inside the SiC source. For a low inert gas pressure (e.g. 10 mbar) it is concluded that the axial temperature gradient inside the source material needs to be decreased to less than ca. 10 K/cm.

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