Production of gradient ultrafine-grained hard alloys from powders obtained from scrap VK15 alloy dispersed in water and scrap VK8 alloy dispersed in oil

2021 ◽  
pp. 84-90
Author(s):  
M. I. Dvornik ◽  
E. A. Mikhaylenko
Keyword(s):  
Carbon Concentration ◽  
Low Cost ◽  
Tool Material ◽  
Sintered Alloy ◽  
Hard Alloys ◽  
Laboratory Unit ◽  
Hard Surface ◽  
Initial Carbon ◽  
Electrospark Dispersion ◽  
Vk15 Alloy

An experiment has been carried out aimed at producing a low-cost tool material which would have an extra hard surface and a crack resistant base phase. A double-layer gradient alloy was produced out of powders with excessive and insufficient carbon obtained from alloys VK8 and VK15 by electrospark dispersion. To obtain the initial powder, plates of the VK8 alloy scrap material initially containing 5.6% of carbon were dispersed in oil. This caused excessive carbon (3.1%), which was then partially reduced to 0.6% by CO2 heat treatment. The VK15 alloy with 5.3% of initial carbon was dispersed in water to achieve an insufficient carbon concentration (2.8 %) in it. It was then heat treated in the CO atmosphere to partially lower the carbon concentration to 0.7%. The dispersed powder was found to consist of spherical microparticles, as well as agglomerated nanoparticles obtained through crystallization of liquid and vapour phases. Mixing of tungsten and cobalt phases resulted in much smaller diameters of WC grains in the newly sintered alloy. This combination of deviations in the carbon concentration between the layers helped maintain the unequal concentration of cobalt (8 and 15%) and thus ensure an extra hard surface (1820HV) and a crack resistant base (14.2 MPa√m). Analysis was carried out to estimate the power costs, as well as the performance of the laboratory unit used for electrospark dispersion of hard alloys.

scholarly journals Mathematical Modeling of Carbon Flux Parameters for Low-Pressure Vacuum Carburizing with Medium-High Alloy Steel

Coatings ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1075
Author(s):  
Haojie Wang ◽  
Jing Liu ◽  
Yong Tian ◽  
Zhaodong Wang ◽  
Xiaoxue An
Keyword(s):  
Carbon Concentration ◽  
Carbon Flux ◽  
Carbon Fluxes ◽  
Low Pressure ◽  
Process Conditions ◽  
Flux Method ◽  
Vacuum Carburizing ◽  
Initial Carbon ◽  
Vacuum Carburization ◽  
And Diffusion

Low-pressure vacuum carburizing adopts a pulse process mode to improve the carburizing efficiency and reduces gas and energy consumption. Carbon flux is the key to accurately control the time of strong infiltration and diffusion in each pulse. In order to obtain the carbon fluxes with various materials under diffident carburizing process conditions, an evenly segmented carbon flux method is proposed. A systematic study with each model using different materials (12Cr2Ni4A, 16Cr3NiWMoVNbE, and 18Cr2Ni4WA represent different initial carbon concentrations and different alloy compositions), carburizing temperatures, and carburizing pressures to determine the effect of these conditions on carbon flux is conducted. Compared with traditional segmented carbon flux method, an evenly segmented carbon flux method can predict the actual carbon flux more precisely and effectively in order to finely control the pulse carburization process. The paper also indicates that carbon fluxes increase with the increase of pressure. The optimal carburization pressure for low-pressure vacuum carburization is 300 Pa. Raising the carburization temperature to 980 °C instead of 920 °C can increase effective carbon flux by more than 30%. Among the material compositions, alloy content has the biggest impact over the carbon, initial carbon concentration the second, and saturated carbon concentration the third biggest impact.

Study on Parameters Optimization of Ceramic Machining Process

2011 ◽  
Vol 418-420 ◽  
pp. 1338-1341
Author(s):  
Qiang Wang ◽  
Ying Ying Zeng ◽  
Xu Guang Min
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Cutting Speed ◽  
Tool Material ◽  
Parameters Optimization ◽  
Machining Process ◽  
Impact Factors ◽  
Surface Model ◽  
Optimal Parameters ◽  
Ceramic Machining

The response surface model is established through application of surface response method, then the main impact factors of ceramic machining are determined, and the process parameters are optimized. The mechanical machining technology of ceramic materials is analyzed, and the corresponding optimal parameters are proposed by cutting tool material, rake angle, clearance angle and edge angle, and three cutting elements as cutting speed, cutting depth and feed. Accord to the optimal parameters, high efficiency, good quality and low cost results can be achieved to machine ceramic parts.

The role of carbon in structural evolution during single step synthesis of nano tantalum carbide

RSC Advances ◽  
2016 ◽  
Vol 6 (110) ◽  
pp. 109174-109184 ◽  
Author(s):  
Loveleen K. Brar ◽  
Gourav Singla ◽  
O. P. Pandey
Keyword(s):  
Reaction Temperature ◽  
Carbon Concentration ◽  
Structural Evolution ◽  
Structural Features ◽  
Single Step ◽  
Tantalum Carbide ◽  
Initial Carbon ◽  
Carbon Coated

Carbon-coated nano TaC has been synthesized at 800 °C in single step from TaO2. Structural features of synthesized cubic TaC depend on the initial carbon concentration. The reaction analysis depicts the role of Mg in lowering the reaction temperature.

Comparative Evaluation of Efficiency of Metal-Cutting Tool by Method of Pendulum Scribing

2015 ◽  
Vol 798 ◽  
pp. 452-456 ◽  
Author(s):  
Boris Y. Mokritskii ◽  
Dmitriy A. Pustovalov ◽  
Alexey Anatolevich Vereschaka
Keyword(s):  
Material Properties ◽  
Comparative Evaluation ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Cost ◽  
Tool Material ◽  
Maximum Width ◽  
Tool Materials ◽  
Metal Cutting Tool ◽  
The Relationship

Method of pendulum scribing was investigated in terms of the possibilities of using this method as a simple-to-use way with a relatively low cost for rapid evaluation of tool material properties. It has been established that by using this method the conditions of loading of the tool material are closest to the real conditions in which the tool operates. Was revealed the relationship between the maximum width and length of the track pendulum scribing and physico-mechanical properties of tool materials. Application of the proposed methodology allows passing to predicting the performance properties of the tool, such as tool life under the specified conditions.

scholarly journals Production of Mo2NiB2 Based Hard Alloys by Self-Propagating High-Temperature Synthesis

2019 ◽  
Vol 38 (2019) ◽  
pp. 683-691 ◽  
Author(s):  
Sevinch Rahimi Moghaddam ◽  
Bora Derin ◽  
Onuralp Yucel ◽  
M. Seref Sonmez ◽  
Meltem Sezen ◽  
...  
Keyword(s):  
High Temperature ◽  
Low Cost ◽  
Absorption Spectrometry ◽  
Hard Alloys ◽  
X Ray Diffraction ◽  
Temperature Synthesis ◽  
High Temperature Synthesis ◽  
Modeling Software ◽  
Cast Alloys ◽  
Series Of Experiments

AbstractMo-Ni-B-Al as-cast alloys containing 35.5-58.7 wt% Mo, 23.0-57.6 wt% Ni, 3.3-5.2 wt% B, and 2.2-13.5 wt% Al were synthesized by Self-Propagating High-Temperature Synthesis (SHS) using a mixture of MoO3, NiO, B2O3 and Al powders in order to obtain low-cost Mo2 NiB2 containing hard materials. The first series of experiments were performed using 1.05 times the stoichiometric amount of Al. In the second series of experiments, FactSage thermochemical modeling software was used to minimize Al increasing the Mo2NiB2 formation in the as-cast alloys. The products were characterized by using atomic absorption spectrometry (AAS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and micro-hardness techniques.

Parameters Affecting the Postshock Wave Relaxation Zone in an Oxygen Carbon Particle Suspension

1986 ◽  
Vol 108 (3) ◽  
pp. 360-365 ◽  
Author(s):  
O. Igra ◽  
G. Ben-Dor ◽  
I. Elperin
Keyword(s):  
Shock Wave ◽  
Mach Number ◽  
Equilibrium State ◽  
Carbon Concentration ◽  
Carbon Particle ◽  
Particle Diameter ◽  
Relaxation Zone ◽  
Initial Carbon ◽  
State Changes ◽  
Shock Wave Mach Number

A parametric study was conducted regarding the effects of the initial carbon concentration, the initial carbon particle diameter, the shock wave Mach number and the preshock suspension pressure on the suspension behavior in the relaxation zone. The suspension was composed of oxygen gas seeded with small carbon particles. It was found that changing either the initial carbon concentration or the shock wave Mach number has a marked effect on the suspension behavior in the relaxation zone and on the eventually reached postshock equilibrium state. Changes in the initial carbon particle diameter (at a constant shock wave Mach number and carbon concentration) has no effect on the postshock equilibrium state, but it does affect the way in which the suspension reaches this equilibrium state. Changes in the preshock suspension pressure has only minor effects on the suspension behavior in the relaxation zone.

scholarly journals Production of Succinic Acid: Effects of C:N Ratio

2019 ◽  
Vol 7 (2) ◽  
pp. 31 ◽  
Author(s):  
Tatiane Araujo Gonzales ◽  
Lucielen Oliveira dos Santos ◽  
Beatriz Torsani Ubeda ◽  
Ranulfo Monte Alegre ◽  
Rosana Goldbeck
Keyword(s):  
Carbon Source ◽  
Succinic Acid ◽  
Carbon Concentration ◽  
Acid Production ◽  
C:N Ratio ◽  
Carbon Sources ◽  
Biomass Growth ◽  
Initial Carbon ◽  
Significant Difference ◽  
Succinic Acid Production

In this work, the effects of different carbon:nitrogen (C:N) ratios, carbon source and initial carbon concentration, in liquid medium used for submerged fermentation, on biomass growth, succinic acid production and yield of product in substrate (YP/S) were studied. It was used three carbon sources as substrate such as glucose, xylose and sucrose and the C:N ratios studied were in the range of 2.5-35. The succinic acid production was best at a C:N ratio of 12.5:1, as much for the succinic acid production as for the yield of product in relation to the substrate (YP/S). For the biomass growth the C:N ratios of 2.5:1, 5:1 and 10:1 had only presented significant difference with regards to the too much assays. The substrate that presents the best results was the glucose with succinic acid concentrations up to 7.5 g.L-1.

scholarly journals Influence of Initial Carbon Concentration on Nitride Layers

2015 ◽  
Vol 15 (5) ◽  
pp. 889-893 ◽  
Author(s):  
Miroslav Pospíchal ◽  
Renata Dvořáková ◽  
Zbyněk Studený ◽  
Zdeněk Pokorný
Keyword(s):  
Carbon Concentration ◽  
Initial Carbon ◽  
Nitride Layers

Analyzing the Mechanisms of Cutting Tool Wear during the Machining of Corrosion-Resistant Steels

2019 ◽  
Vol 973 ◽  
pp. 120-124
Author(s):  
Pham H. Trung ◽  
Juliy L. Chigirinskiy
Keyword(s):  
Chemical Composition ◽  
Wear Rate ◽  
Tool Wear ◽  
Thermophysical Properties ◽  
Cutting Tool ◽  
Tool Material ◽  
Cutting Conditions ◽  
Hard Alloys ◽  
Carbide Tool ◽  
Corrosion Resistant

The study analyzes physicomechanical and thermophysical properties of hard alloys with due regard to their chemical composition; reveals the dependence of both the cutting properties and regularities of carbide tool wear from cutting conditions and thermophysical properties of tool material; describes a significant impact of not only mechanical but, first and foremost, thermophysical properties of instrumental and structural materials on tool wear; and identifies ways to reduce the wear rate of a cutting tool.

scholarly journals Thermomechanical Processing of Cost-Affordable Powder Metallurgy Ti-5Fe Alloys from the Blended Elemental Approach: Microstructure, Tensile Deformation Behavior, and Failure

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1405
Author(s):  
Carlos Romero ◽  
Fei Yang ◽  
Shanghai Wei ◽  
Leandro Bolzoni
Keyword(s):  
Powder Metallurgy ◽  
Tensile Deformation ◽  
Thermomechanical Processing ◽  
Low Cost ◽  
Solution Treatment ◽  
Sintered Alloy ◽  
Blended Elemental ◽  
Β Phase ◽  
Tensile Deformation Behavior ◽  
Interesting Approach

The development of cost-affordable Ti alloys is key for the application of Ti in other industries like the automobile sector. Therefore, a combination of powder metallurgy (PM) and low-cost compositions is an interesting approach. In this article, a cost-affordable PM Ti-5Fe alloy is processed following the blended elemental route and extruded at high temperature to remove porosity. Different extrusion temperatures and heat treatments (i.e., solution treatment and aging, STA) are performed to obtain ultrafine microstructures, and their effect on the mechanical behavior is studied. For extrusions in the β phase, microstructures consist of coarse lamellar colonies, resulting in alloys with improved properties compared to the as-sintered alloy but still lacking toughness due to the failure happening just after necking onset. Extruding in the α + β phase results in a bimodal microstructure of fine elongated primary α and coarse lamellar colonies, and the alloy becomes tougher. STA with aging below the eutectoid temperature of 590 °C leads to a hard but brittle alloy, whereas STA with aging above it results in alloys with strength comparable to the as-extruded conditions and enhanced ductility.

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