scholarly journals INCREASE OF WEAR RESISTANCE OF CUTTING TOOLS FOR PROCESSING IRON-CARBON ALLOYS

2014 ◽  
Author(s):  
Larisa Andreevna Timofeeva ◽  
Anna Leonidovna Komarova
Keyword(s):  
Chemical Composition ◽  
Thermal Processing ◽  
High Performance ◽  
Cubic Boron Nitride ◽  
Cutting Tools ◽  
Thermal Spraying ◽  
Oxide Coatings ◽  
Surface Layers ◽  
Wear Process ◽  
Physico Chemical

The article considers the problem of the development of environmental-friendly technology of drawingof strengthening coatings on cutting tools for processing iron-carbon alloys.The studies have used methods for determining the tribological properties of the tool materialsdepending on the speed of sliding surfaces. In the work of the mechanism of wear process tool cubic boron nitride and metal ceramics. Proposedthe method of application of protective coatings.Given the nature and chemical composition of superhard materials and composite materials proposedand partially tested a method of chemical-thermal spraying of oxide coatings, the essence of which is theimpact (30...60 min) superheated (600 OC) vapour aqueous solution (3 %) of the various salts on the workingsurface of the tool.The technological process of causing of oxide coverages is tested in a laboratory stove, simple,inexpensive, high-performance, ecologically clean.In the future it is necessary to conduct a study of the diffusion and physico-chemical processesoccurring in the surface layers of cutting plates during chemical-thermal processing and as a result ofmechanical treatment. In addition, should continue studies towards a greater variation of the parameters ofthe process of chemical-thermal processing tool - temperature, chemical composition and concentration ofthe saturating environment. This will enable them optimization, as well as specify the chemical compositionof the coating. 

scholarly journals Development of actions on optimization of chemical composition of carburized steel grade 16MnCrS5 to eliminate the causes of the growth of large austenite grains

2019 ◽  
pp. 49-56 ◽  
Author(s):  
I. A. Kovaleva ◽  
I. A. Ovchinnikova ◽  
S. V. Stefanovitch
Keyword(s):  
Grain Size ◽  
Chemical Composition ◽  
High Performance ◽  
Internal Combustion Engines ◽  
Cutting Tools ◽  
Steel Grade ◽  
Fine Grained ◽  
Carburized Steel ◽  
Fine Grained Structure ◽  
Steel Grades

The problem of friction, wear of machine parts and cutting tools, the need to increase the life of machines makes the task of creating new high-performance, energy-saving technologies of hardening one of the main in engineering. In mechanical engineering, the problem of improving the physical, mechanical and operational properties in thin surface layers (~10 microns) of such parts as shafts, gears, measuring tools, drills, cylinders of internal combustion engines, etc. is important. Currently, these tasks are often solved by applying reinforcing coatings. Cementation is economical. The technology of cemented steels smelting, which is currently used by metallurgical plants, does not ensure stable production of fine-grained structure in products. At the same time, the capacity of machines and units are growing, and to obtain parts that can withstand higher loads while maintaining their overall dimensions, new steel grades are needed. The complexity of the configuration of gears with a thin tooth and a massive sleeve, and the need for minimal warping make heat treatment as difficult and responsible as a complex tool, such as shaped cutters. Therefore, for the manufacture of gears you want to assign steel with small hereditary grain size. In this article we will focus on the development and production of cemented steel in the conditions of OJSC «BSW – Management Company of Holding «BMC», in particular, the steel brand 16MnCrS5 commissioned by the European manufacturer of gearboxes and motors. To determine the grain size of the metal must be subjected to special types of processing for the manifestation of certain characteristics. These results allow us to draw conclusions about the need to adjust the chemical composition of steel grade 16MnCrS5 by introducing a system of modifying elements, which will reduce the tendency of steel to overheating, therefore, reduce the size of austenitic grains. On the basis of the revealed regularities on the influence of carbide-forming elements, a further system of steel modification is determined, which includes a complex of elements V, Nb, Ti.

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

Electrochemical Deposition of Polypyrrole Nanostructures for Energy Applications: A Review

2020 ◽  
Vol 16 (4) ◽  
pp. 462-477 ◽  
Author(s):  
Patrizia Bocchetta ◽  
Domenico Frattini ◽  
Miriana Tagliente ◽  
Filippo Selleri
Keyword(s):  
Lithium Batteries ◽  
High Performance ◽  
Relevant Literature ◽  
Chemical Parameters ◽  
Energy Devices ◽  
Energy Applications ◽  
Physico Chemical ◽  
Potential Applications ◽  
Template Free ◽  
Cathodic Polymerization

By collecting and analyzing relevant literature results, we demonstrate that the nanostructuring of polypyrrole (PPy) electrodes is a crucial strategy to achieve high performance and stability in energy devices such as fuel cells, lithium batteries and supercapacitors. In this critic and comprehensive review, we focus the attention on the electrochemical methods for deposition of PPy, nanostructures and potential applications, by analyzing the effect of different physico-chemical parameters, electro-oxidative conditions including template-based or template-free depositions and cathodic polymerization. Diverse interfaces and morphologies of polymer nanodeposits are also discussed.

scholarly journals Feasibility of Cobalt-Free Nanostructured WC Cutting Inserts for Machining of a TiC/Fe Composite

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3432
Author(s):  
Edwin Gevorkyan ◽  
Mirosław Rucki ◽  
Tadeusz Sałaciński ◽  
Zbigniew Siemiątkowski ◽  
Volodymyr Nerubatskyi ◽  
...  
Keyword(s):  
Cubic Boron Nitride ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Machined Surface ◽  
Powder Consolidation ◽  
Plasma Sintering ◽  
Cutting Inserts ◽  
Spark Plasma ◽  
And Performance ◽  
Nanostructured Tungsten Carbide

The paper presents results of investigations on the binderless nanostructured tungsten carbide (WC) cutting tools fabrication and performance. The scientific novelty includes the description of some regularities of the powder consolidation under electric current and the subsequent possibility to utilize them for practical use in the fabrication of cutting tools. The sintering process of WC nanopowder was performed with the electroconsolidation method, which is a modification of spark plasma sintering (SPS). Its advantages include low temperatures and short sintering time which allows retaining nanosize grains of ca. 70 nm, close to the original particle size of the starting powder. In respect to the application of the cutting tools, pure WC nanostructure resulted in a smaller cutting edge radius providing a higher quality of TiC/Fe machined surface. In the range of cutting speeds, vc = 15–40 m/min the durability of the inserts was 75% of that achieved by cubic boron nitride ones, and more than two times better than that of WC-Co cutting tools. In additional tests of machining 13CrMo4 material at an elevated cutting speed of vc = 100 m/min, binderless nWC inserts worked almost three times longer than WC-Co composites.

scholarly journals Biofoam of Spittlebug, Poophilus costalis (Walker): Preferential Sites, Temperature Regulation, Chemical Composition and Antimicrobial Activity

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 340
Author(s):  
Kitherian Sahayaraj ◽  
Balakrishnan Saranya ◽  
Samy Sayed ◽  
Loko Yêyinou Laura Estelle ◽  
Koilraj Madasamy
Keyword(s):  
Antimicrobial Activity ◽  
Chemical Composition ◽  
High Performance ◽  
Host Plants ◽  
Ground Level ◽  
College Campus ◽  
The Other ◽  
Mimosa Pudica ◽  
Ft Ir ◽  
Gas Chromatography Mass Spectroscopy

The foam produced by nymphs of Poophilus costalis on eleven different host plants belonging to eight families on St. Xavier’s College campus in India was studied over five months. The chemical composition and antimicrobial activity of these biofoams were investigated. The results revealed that P. costalis preferred Theporsia purpurea and Mimosa pudica for laying their eggs and producing foam, over the other tested plants. P. costalis produce their foam on either nodes or internodes on monocotyledons (30%) (p < 0.05), whereas on dicotyledons, they produce more foam on the stems (63.8%) than on the leaves (6.2%) (p < 0.01). The number of nymphs in each piece of foam from P. costalis varied from 1 to 3 (mean = 1.8 per plant). They produced their foam (5.7 to 45.2 cm) from the ground level on a plant. The length and breadth of a piece of foam ranged from 1.0 to 3.9 cm and 0.6 to 4.7 cm, respectively. The foam tended to be cooler than the environment. Qualitative profiling showed that the foam consists of carbohydrates, including maltose; trypsin; amino acids; protease. The foam was also analyzed using a spectrophotometer, Fourier transform infrared spectroscopy (FT-IR), gas chromatography–mass spectroscopy (GC-MS), and high-performance liquid chromatography (HPLC). The antimicrobial activity of the biofoam was the greatest against Staphylococcus aureus, the growth of which was reduced by 55.9 ± 3.9%, suggesting that the foam could be used as an antimicrobial product. However, no activities were observed against Fusarium oxysporum and Candida albicans.

scholarly journals Remaining Useful Life Prediction of Cutting Tools Using an Inverse Gaussian Process Model

2021 ◽  
Vol 11 (11) ◽  
pp. 5011
Author(s):  
Yuanxing Huang ◽  
Zhiyuan Lu ◽  
Wei Dai ◽  
Weifang Zhang ◽  
Bin Wang
Keyword(s):  
Surface Roughness ◽  
Failure Criterion ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Remaining Useful Life ◽  
Model Parameters ◽  
Inverse Gaussian ◽  
Wear Process ◽  
Useful Life ◽  
Dynamic Wear

In manufacturing, cutting tools gradually wear out during the cutting process and decrease in cutting precision. A cutting tool has to be replaced if its degradation exceeds a certain threshold, which is determined by the required cutting precision. To effectively schedule production and maintenance actions, it is vital to model the wear process of cutting tools and predict their remaining useful life (RUL). However, it is difficult to determine the RUL of cutting tools with cutting precision as a failure criterion, as cutting precision is not directly measurable. This paper proposed a RUL prediction method for a cutting tool, developed based on a degradation model, with the roughness of the cutting surface as a failure criterion. The surface roughness was linked to the wearing process of a cutting tool through a random threshold, and accounts for the impact of the dynamic working environment and variable materials of working pieces. The wear process is modeled using a random-effects inverse Gaussian (IG) process. The degradation rate is assumed to be unit-specific, considering the dynamic wear mechanism and a heterogeneous population. To adaptively update the model parameters for online RUL prediction, an expectation–maximization (EM) algorithm has been developed. The proposed method is illustrated using an example study. The experiments were performed on specimens of 7109 aluminum alloy by milling in the normalized state. The results reveal that the proposed method effectively evaluates the RUL of cutting tools according to the specified surface roughness, therefore improving cutting quality and efficiency.

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