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.

High-Pressure Synthesis of High-Purity and High-Performance Diamond and cBN Ceramics

2006 ◽  
Vol 45 ◽  
pp. 885-892 ◽  
Author(s):  
Hitoshi Sumiya
Keyword(s):  
High Pressure ◽  
Diffusion Process ◽  
High Purity ◽  
High Performance ◽  
High Efficiency ◽  
Cutting Tools ◽  
Polycrystalline Diamond ◽  
High Hardness ◽  
Secondary Phases ◽  
Fine Grained

High-purity, single-phase polycrystalline diamond and cBN have been successfully synthesized by direct conversion sintering from graphite and hBN, respectively, under static high pressure and high temperature. The high-purity polycrystalline diamond synthesized directly from graphite at ≧15 GPa and 2300-2500 °C has a mixed texture of a homogeneous fine structure (grain size : 10-30 nm, formed in a diffusion process) and a lamellar structure (formed in a martensitic process). The polycrystalline diamond has very high hardness equivalent to or even higher than that of diamond crystal. The high-purity polycrystalline cBN synthesized from high-purity hBN at 7.7 GPa and 2300 °C consists of homogeneous fine-grained particles (<0.5 μm, formed in a diffusion process). The hardness of the fine-grained high-purity polycrystalline cBN is obviously higher than that of single-crystal cBN. The fine microstructure features without any secondary phases and extremely high hardness of the nano-polycrystalline diamond and the fine-grained polycrystalline cBN are promising for applications in next-generation high-precision and high-efficiency cutting tools.

Structural Characterization of FeAl28Cr5 Alloy Deformed in the Hot Torsion Process

2016 ◽  
Vol 246 ◽  
pp. 43-46 ◽  
Author(s):  
Iwona Bednarczyk ◽  
Magdalena Jabłońska
Keyword(s):  
Plastic Deformation ◽  
Grain Size ◽  
Structural Changes ◽  
Al Alloys ◽  
Dynamic Processes ◽  
Fine Grained ◽  
Average Grain Size ◽  
Fine Grained Structure ◽  
Hot Torsion

Current research in the field of iron aluminides are directed towards to understand the structural phenomena occurring during plastic deformation of these alloys. The obtained results of the study and collected informations will be used to determine the description of the structural changes taking place during hot deformation of Fe ̶Al alloys. The article presents the results of the study of the alloy FeAl28Cr5 deformed by hot torsion in temperature range of 800÷1100°C and a strain rate of 0.1 s-1. The analysis of the structure of the alloy FeAl28Cr5 allowed to reveal changes caused by dynamic processes of deformation. The results of torsion tests show the possibility to obtain a fine-grained structure with of parameters of the processes (T=1000°C, 1100°C) and strain of ε=40. After deformation at strain of (ε=40) the structure consists of fine grains with a misorientation angle higher than 15°, and the average grain size diameter D=28.5 micrometers. Deformation at a temperature of T=1000°C and 1100°C is accompanied by superplastic flow effect.

Investigation of consequences of violation of technology of manufacture of individ-ual elements of BMP-2 track tape

2021 ◽  
pp. 61-68
Author(s):  
R. Kuzmenko ◽  
М. Kovba ◽  
O. Popovchenko ◽  
Т. Kovbasiuk ◽  
S. Shvachko
Keyword(s):  
Heat Treatment ◽  
Spectral Analysis ◽  
Chemical Composition ◽  
Materials Science ◽  
Density Measurement ◽  
Science Research ◽  
Steel Grade ◽  
Military Equipment ◽  
Steel Grades ◽  
The Military

The operation of the BMP-2 infantry fighting vehicle was accompanied by periodic failures of the tracked belts. This is due to the breakage of the fixing bolts of the track pins fastening bracket, and thus the military equipment became stationary. Establishing the causes of the destruction of the bolt fixing the staple of the track fingers of the tracked belt of military equipment was carried out using a complex of instrumental materials science research. In particular, the chemical composition of the material from which the bolts and staples were made was determined by the spectral analysis; the fracture surface of the fixing bolt was investigated by the macroanalysis; the microstructure of the bolts was examined using optical microscopy; the microhardness and density of the bolt material was measured. The bolts were made from steel grades 30XM and 33XC, and not from the recommended steel grade 38XC. The macrostructure of the broken bolt corresponds to the shearing structure. The microstructure showed rolling and heat treatment defects. Density measurement confirmed the presence of heat treatment defects. The imperfection of the applied heat treatment was confirmed by measuring the microhardness. A complex of metallurgical research has established the main cause of the destruction of the bolts. It consists in an unsuccessful design of bolts and brackets, an incorrectly selected steel grade with defects in rolling and heat treatment.

Influences of Pulse Current Density on the Characteristics of Ni-W-P-CeO2-SiO2 Composite Coatings

2011 ◽  
Vol 418-420 ◽  
pp. 856-860 ◽  
Author(s):  
Rui Dong Xu ◽  
Da Cheng Zhai ◽  
Shuang Li Hu
Keyword(s):  
Chemical Composition ◽  
Current Density ◽  
Pulse Current ◽  
Composite Coatings ◽  
Average Current Density ◽  
Fine Grained ◽  
Fine Grained Structure ◽  
Average Current ◽  
S Deposition ◽  
Microhardness Tester

Square-wave double pulse current was used to electrodeposit Ni-W-P-CeO2-SiO2composite coatings in fine-grained structure on the surface of carbon steel, influences of forward pulse average current density, +Jm, in the range of 5~25A/dm2on characteristics of the composite coatings were researched, and the chemical compositionSubscript texts, deposition rate, microhardness and microstructures were evaluated by EDX, SEM and Microhardness tester. The results show that the uniform composite coatings can be obtained at +Jmof 20A/dm2, which possess higher microhardness of 735Hv. The grains sizes of the composite coatings decrease when +Jmis increased from 5A/dm2to 20A/dm2, while the reappearance of large grains structure at 25A/dm2.

Compressive and Flexural Strength of Fine Grained Mortar Containing Rice Husk Ash: A Review

2014 ◽  
Vol 1051 ◽  
pp. 757-762 ◽  
Author(s):  
Zalipah Jamellodin ◽  
Mohd Saman Hamidah ◽  
Suraya Hani Adnan ◽  
Noor Shuhada Mohammad ◽  
Wan Yuslinda Wan Yusof
Keyword(s):  
Grain Size ◽  
Rice Husk ◽  
High Performance ◽  
Rice Husk Ash ◽  
Partial Replacement ◽  
Innovative Technology ◽  
Future Research ◽  
Binder System ◽  
Fine Grained ◽  
Pozzolanic Additives

Fine Grained Mortar (FGM) offers a new innovative technology binder system to strengthen or repair concrete structures. The innovative technique is achieved by using a small maximum grain size of 1 mm for the mortars. Therefore, less than 2 mm of mortar thickness would be fitted between the strengthened layers. FGM also has high binder contents, by adopting different pozzolanic additives and high performance of plasticizers. Recently, the utilisation of supplementary of cementing materials such as Fly Ash (FA) and Rice Husk Ash (RHA) has a become an important in concrete industry. It has demonstrated significant influence in improving the strength of mortar. Most of the previous studies have focused on the FA to be replaced in the FGM. There is still lacking of research of using other pozzolanas in making FGM. This paper presents an overview on the use of FA and RHA as partial replacement of cement in mortar and FGM as well as future research that will be conducted by the authors.

Microstructures and Strength of Hot-Rolled Mg-Zn-Y Alloys

2011 ◽  
Vol 291-294 ◽  
pp. 137-140
Author(s):  
Yao Min Zhu ◽  
Qiu Ran Gao ◽  
Feng Zhang Ren ◽  
Shi Jie Fang
Keyword(s):  
Grain Size ◽  
Tensile Strength ◽  
Hot Rolling ◽  
Rolling Process ◽  
Recrystallization Process ◽  
Fine Grained ◽  
Hot Rolling Process ◽  
Fine Grained Structure ◽  
Cast Alloys ◽  
Hot Rolled

The effects of the hot-rolling process on microstructures and strength were investigated for two kinds of magnesium alloy Mg-Zn-Y and Mg-Zn-Y-Nd. In comparison with the as-cast alloys, the tensile strength of Mg-Zn-Y and Mg-Zn-Y-Nd both increases 45%, whereas their elongation decreases 73%, 60% via hot-rolling process, respectively. The results show that the dynamic recrystallization process and the pining effect of I-phase during hot rolling contribute to the fine-grained structure formation. The hot-rolling process has refined the grain size greatly.

scholarly journals VECTOR CLOCK TRACING AND MODEL BASED PARTITIONING FOR DISTRIBUTED EMBEDDED SYSTEMS

2014 ◽  
pp. 324-332
Author(s):  
Robert Hoettger ◽  
Burkhard Igel ◽  
Erik Kamsties
Keyword(s):  
Performance Optimization ◽  
High Performance ◽  
Distributed Embedded Systems ◽  
Control Engineering ◽  
Fine Grained ◽  
Model Based ◽  
Optimal Load ◽  
Vector Clock ◽  
Fine Grained Structure ◽  
High Degree

Tracking, partitioning and tracing in modern dynamic high performance computing systems are three of the most innovative and important development aspects for performance optimization purposes and state-of-the-art advanced quality. This paper discusses these three aspects with respect to distributed systems and proposes new mechanisms for an advanced utilization of software in this domain. We present a specific tracking mechanism via vector clocks for model and code partitioning purposes and the determination of causality relations. Further, a tracing approach for an effective analysis and thereby utilization of code and the corresponding architecture is introduced. The combination of both approaches leads to a high degree of parallelism and a fine-grained structure of execution units, that further traced, supports a precise analysis of synchronous and asynchronous system’s behavior as well as an optimal load balancing. The mechanisms are introduced with respect to a model based control engineering tool and event diagrams.

STRUCTURAL PROPERTIES AND ABRASIVE- WEAR RESISTANCE OF BRINAR 400 AND BRINAR 500 STEELS

Tribologia ◽  
2017 ◽  
Vol 273 (3) ◽  
pp. 67-75 ◽  
Author(s):  
Łukasz KONAT ◽  
Jerzy NAPIÓRKOWSKI ◽  
Beata BIAŁOBRZESKA
Keyword(s):  
Wear Resistance ◽  
Abrasive Wear ◽  
Sandy Loam ◽  
High Strength ◽  
Abrasive Wear Resistance ◽  
Martensitic Steels ◽  
Fine Grained ◽  
Carbide Phases ◽  
Fine Grained Structure ◽  
Steel Grades

In the paper, microstructures and the examination results of abrasive-wear resistance of steel grades Brinar 400 and Brinar 500 are presented. It was found on the grounds of light and electron scanning microscopy that these steels are characterised by subtle differences in microstructures, influencing their mechanical and usable properties. In as-delivered condition, the steels have fine-grained structure with post-martensitic orientation, containing few particles of carbide phases. Such microstructures of Brinar steels and the performed chemical analyses indicate that their properties are formed during specialised operations of thermo-mechanical rolling. Generally, it can be said that the examined steels were designed according to the accepted standards of material engineering, related to low-alloy, high-strength, and abrasive-wear resistant martensitic steels. According to the above, the obtained results of structural examinations of Brinar 400 and Brinar 500 steels were referred to real abrasive-wear indices obtained by the spinning bowl method with use of various abrasive soil masses. The tests carried-out in light soil (loamy sand), medium soil (sandy loam), and in heavy soil (loam), as well as hardness measurements showed strict dependence of abrasive-wear indices on microstructures and the heattreatment condition of the examined steels. Examination results of abrasive-wear resistance of Brinar steels were compared with those of steel 38GSA in normalised conditions.

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. 

The Prediction of Hardenability using Neural Networks

2014 ◽  
Vol 59 (1) ◽  
pp. 133-136 ◽  
Author(s):  
M. Knap ◽  
J. Falkus ◽  
A. Rozman ◽  
K. Konopka ◽  
J. Lamut
Keyword(s):  
Neural Networks ◽  
Chemical Composition ◽  
Steel Grade ◽  
Chemical Compositions ◽  
Heterogeneous Database ◽  
High Quality ◽  
Model Predictions ◽  
Steel Grades ◽  
Improved Model ◽  
Influential Parameters

Abstract The objective of the research that has been presented was to model the effect of differences in chemical composition within one steel grade on hardenability, with a very broad and heterogeneous database used for studying hardness predictions. This article presents the second part of research conducted with neural networks. In the previous article [1] the most influential parameters were defined along with their weights and on the basis of these results, an improved model for predicting hardenability was developed. These developed neural networks were applied to model predictions of hardenability for three steel grades VCNMO150, CT270 and 42CrMoS4. The results proved that the correlation between the chemical composition differences within a chosen steel grade and the hardness changes can be modeled. If the database is big enough, predictions would be accurate and of high quality. But for a less comprehensive database, the differences in hardness predictions for various chemical compositions of the steel grade concernedwere observable.

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