scholarly journals Factors Affecting the Wear Resistance of Forging Tools

2017 ◽  
Vol 62 (3) ◽  
pp. 1567-1576 ◽  
Author(s):  
M. Zwierzchowski
Keyword(s):  
Surface Layer ◽  
Working Conditions ◽  
Laboratory Tests ◽  
Effect Of Temperature ◽  
Laboratory Studies ◽  
Fem Modeling ◽  
Factors Affecting ◽  
Flat Surfaces ◽  
Mechanical Fatigue ◽  
Diffusion Layers

AbstractThe durability of forging tools is a function of many variables: tool heat treatment, surface quality, temperature, pressure, number of forgings, diffusion layers (nitriding) and many others. The objective of study was to analyze and compare the working conditions of forging tools. For the analysis of selected flat surfaces of tools. Analyzed forging dies subjected to normal use. Presented results of laboratory tests . The effect of temperature and time on the properties of the surface layer of forging tools. The results were compared with the literature data. This article shows the results of microhardness tests for forging dies which have forged the corresponding number of forgings. The results of laboratory studies on microhardness of hot working steel 1.2344 in the furnace at various temperatures and time are also presented. The working conditions of the forging tools are very complex. The most often described in the literature are: thermal fatigue, abrasive wear, mechanical fatigue and cracks. The article discusses the effects of increased temperature on the surface properties of forging tools. Forging dies were made of hot work tool steel 1.2344. FEM modeling of changes in the surface layer should take into account changes in tool hardness as a function of time (number of forgings).

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.

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.

Laboratory Tests on Engineering Properties of Wind-Blown Sand

2012 ◽  
Vol 170-173 ◽  
pp. 706-709
Author(s):  
Zhao Lin Jia ◽  
Shu Wang Yan ◽  
Zhi Liang Huo
Keyword(s):  
Water Content ◽  
Laboratory Tests ◽  
Fine Sand ◽  
Engineering Properties ◽  
Grain Composition ◽  
Factors Affecting ◽  
Compaction Curve ◽  
Main Factors ◽  
Dry And Wet Conditions ◽  
Compaction Properties

By means of laboratory tests and theoretical calculation, the physical, mechanical properties and compaction mechanism of the wind-blown sand are studied to deal with the problem of how to use the wind-blown sand as roadbed materials. It is revealed that water content doesn’t affect the compressibility and the shear strength of the wind-blown sand obviously and the wind-blown sand can be compacted both in dry and wet conditions. The compaction curve of the ordinary fine sand is consistent with that of wind-blown sand and the main factors affecting the compaction properties are the grain composition, water content and compaction work.

Results of the experimental bits bench test, equipped with the compound built-up layers

2020 ◽  
pp. 52-56
Author(s):  
V.N. Gadalov ◽  
V. M. Brodsky ◽  
E.A. Filatov ◽  
A.V. Filonovic
Keyword(s):  
Tungsten Carbide ◽  
Laboratory Tests ◽  
Bench Test ◽  
Laboratory Studies ◽  
Induction Method ◽  
Gas Flame ◽  
Flame Method ◽  
Drilling Bit ◽  
Pilot Tests

The article shows the results of performance laboratory studies of compound built-up layers, as well as benches of the pilot tests of the drilling bit rolling cutters, equipped on the bit gage surface of the compound built-up layer; the hardening layers were located along the gage teeth contour. The cast tungsten carbide building-up welding on experimental bits was carried out using a gas-flame method. The induction method of building-up welding was implemented on the rolling cutters of the serial bits. The article shows the results of comparative indicators of serial and experimental bits when their processing on the bench. It was found that experimental bits were more efficient than the serial ones. The estimation of the performance laboratory tests results was confirmed by tests on the bench under pilot conditions of the rolling cutter bits drilling, equipped on the bit gage surface by the compound built-up layer.

Stresses in the Surface Layer and Hydrogen Absorption and Diffusion in Cavitation Condition

2014 ◽  
Vol 225 ◽  
pp. 131-138
Author(s):  
Jarosław Chmiel ◽  
Jolanta Baranowska ◽  
Roman Jędrzejewski ◽  
Arkadiusz Rzeczycki
Keyword(s):  
Surface Layer ◽  
Stress State ◽  
Hydrogen Absorption ◽  
Surface Layers ◽  
Fem Modeling ◽  
And Diffusion

Cavitation attack in liquids generated a various states of stresses in surface layers of metals. Differences in stress state effects on hydrogen absorption activated by the cavitation implosion. Results of XRD investigation and FEM modeling shows on inhomogenity of process.

scholarly journals Laboratory studies of homing orientation in the eastern red-spotted newt, Notophthalmus viridescens

1987 ◽  
Vol 131 (1) ◽  
pp. 215-229 ◽  
Author(s):  
J. B. Phillips
Keyword(s):  
Water Temperature ◽  
Laboratory Tests ◽  
Notophthalmus Viridescens ◽  
Magnetic Orientation ◽  
Laboratory Studies ◽  
Navigational System ◽  
South Axis ◽  
Magnetic North ◽  
Migratory Period ◽  
East West

The orientation behaviour of adult male eastern red-spotted newts (Notophthalmus viridescens) was studied in laboratory tests. Newts were collected from ponds located 10–30 km from the laboratory, and housed in water-filled, all-glass aquaria located in a greenhouse or outdoors adjacent to the laboratory building. The aquaria were aligned on the magnetic north-south axis. Newts were tested in a dry, enclosed arena in four magnetic fields: the ambient magnetic field (magnetic north at North) and three altered fields (magnetic north rotated to East, West or South). Newts tested during January-March exhibited weak bimodal magnetic orientation along the axis of the holding tank. However, during the spring migratory period (April until early May), the bimodal response shifted to coincide with the direction of the pond from which the newts had been collected. Much stronger unimodal orientation was elicited by elevating the water temperature to 33–34 degrees C immediately prior to testing. If newts were held in a training tank with an artificial shoreline at one end and exposed to elevation of water temperature after several days of stable water temperatures, they exhibited unimodal shoreward orientation and did not show the seasonal switch to homing behaviour observed in the earlier tests. If, however, the elevation of water temperature followed a period of fluctuating water temperature (over a 20 degrees C range), the newts exhibited strong unimodal orientation in the direction of the pond from which they had been collected. These results suggest that newts possess a navigational system that enables them to home from distances in excess of 20 km. Moreover, these experiments provide the first opportunity to examine the sensory basis of navigational ability in any animal under controlled laboratory conditions.

scholarly journals Factors that affect employee motivation at Bentre Import Export Joint- stock Corporation (Betrimex)

2020 ◽  
Vol 5 (1) ◽  
pp. first
Author(s):  
Huỳnh Thanh Tú ◽  
Ung Hoàng Khang
Keyword(s):  
Regression Analysis ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Working Conditions ◽  
Work Performance ◽  
Employee Motivation ◽  
Factors Affecting ◽  
Research Results ◽  
Exploratory Data ◽  
Stock Corporation

The research on factors that affect employee motivation at Bentre Import Export Joint- stock Corporation (Betrimex) has special significance in motivating employees, attracting and retaining talent, thereby helping the Corporation improve work performance. During the research, 300 employees working at Betrimex were surveyed and 250 employees with valid answer sheets were selected, survey data was processed with the SPSS software and the research model through scale reliability analysis, exploratory data analysis, correlation analysis and multiple regression analysis was tested. The research results have shown 07 factors affecting employee motivation at Betrimex, measured through 37 observed variables and including the pay, bonuses, benefits, allowances, working conditions, relationships with colleagues and relationships with superiors. Where the pay (b = 0.403) is the factor that has the most powerful influence on employee motivation and working conditions (b = 0.171) have the least influence on employee motivation. The results of multiple regression analysis have also showed that the adjusted R2 is 0.732. Thus, 07 independent variables can explain 73.2% of the variations of the dependent variables. Also, the research results have tremendous implications for developing strategies and plans for human resources development of Betrimex in the future.

scholarly journals Sanitary and hygienic assessment of working conditions of civil aviation pilots

2021 ◽  
Vol 100 (10) ◽  
pp. 1084-1094
Author(s):  
Igor V. Bukhtiyarov ◽  
Evgeny V. Zibarev ◽  
Nicolay N. Kuryerov ◽  
Oksana V. Immel
Keyword(s):  
Working Conditions ◽  
Statistical Treatment ◽  
Civil Aviation ◽  
Work Intensity ◽  
Local Vibration ◽  
Factors Affecting ◽  
Separate Form ◽  
Legislative Framework ◽  
Aviation Pilots

Introduction. The analysis of working conditions of pilots of civil aviation aircraft has been carried out according to the data of sanitary and hygienic characteristics (SHC). The non-compliances with hygiene standards for several factors have been established at the same time in all SHC. Materials and methods. The 220 SHC of pilots, who had been examined in the clinic of FSBSI RIOH due to suspicion of occupation disease from 2015 to 2019, conducting flights by plane (49%) and helicopter (51%) were analyzed. The methods of account of acoustic load, hygiene assessment and classification of working conditions, peer review methods, and statistical treatment methods have been used. Results. The working conditions, according to the criteria of the Guide R 2.2.2006-05, are assigned to the following classes: 3.2 - in 26%; 3.3 - in 41%; 3.4 - in 33%. Exceeding the permissible equivalent noise levels was recorded at 92% of workplaces. According to SHC, the exceedances were from 1.2 dB to 34.5 dB (class 3.1-3.4). In assessing the work intensity in 83% of cases from 5 to 11 indicators of class 3.2 were recorded. It has determined class 3.3 of work intensity. The levels of general vibration exceeded hygiene standards in 48% of cases (class 3.1- 3.2), local vibration - in 8% (class 3.1-3.2), microclimate parameters - in 67% (class 3.1-3.2), labour severity - in 22% (class 3.1-3.3), less often there were discrepancies in light (6%) and chemical factor (2%). Conclusion. According to a combination of factors, the overall assessment of working conditions of the pilots of civil aviation aircraft in 74% of cases is assigned to classes 3.3-3.4. However, the disadvantages and errors in filling out the SHC can underestimate the degree of harmfulness of the work. To improve the procedure of establishing the connection between the disease, and the profession it is necessary to amend the legislative framework to obtain objective information about the levels of factors affecting pilots, develop a separate form of SHC of working conditions of pilots, detailed instructions about the rules of filling out SHC.

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