WEAR TESTING OF BUTTONS IN BITS FOR BLASTHOLE DRILLING

Tribologia ◽  
2018 ◽  
Vol 278 (2) ◽  
pp. 13-19 ◽  
Author(s):  
Rafał DUDEK ◽  
Krzysztof WŁADZIELCZYK
Keyword(s):  
Abrasive Wear ◽  
Blast Hole ◽  
Operating Time ◽  
Operating Conditions ◽  
Wear Testing ◽  
Hole Drilling ◽  
Drilling Process ◽  
Rock Mining ◽  
Drilling Rigs ◽  
The Impact

The article presents the results of the wear testing of buttons in selected types of bits with the diameter of 95 mm used for blast hole drilling in a rock mining. The purpose of the testing was to determine the type of the wear of peripheral and frontal buttons in the actual operating conditions of bits and the impact of selected parameters of the drilling process and of sharpening the buttons on their durability. Tests of button wear were carried out by the blasthole drilling in deposits of the Devonian and Triassic dolomites. For the blast hole drilling with tested bits, drilling rigs HSB 500 and HBM 60, equipped with down-the-hole impact mechanisms VKP 95-2 from the company Permon were used. Tests on the wear of buttons were carried out according to the adopted methodology, taking into account both their abrasive wear and wear through crushing or falling out. During the drilling of holes, every effort was made to use fixed values of parameters of the drilling process, except for the value of drill stem rotation speed, because one of objectives of the research was to determine its impact on the abrasive wear of tested bits buttons. The obtained results of tests proved that the predominant type of wear of button bits for blast hole drilling is an abrasive wear of frontal buttons, and regular sharpening of the buttons allows increasing the operating time of rock bits by up to 35%.

scholarly journals Performance analysis of the working surface of the rails from test batches on the Test Loop of JSC “VNIIZhT”

2018 ◽  
Vol 77 (3) ◽  
pp. 141-148
Author(s):  
M. Yu. Khvostik ◽  
I. V. Khromov ◽  
O. A. Bykova ◽  
G. A. Beresten’
Keyword(s):  
Wear Resistance ◽  
Operating Time ◽  
Operating Conditions ◽  
Continuous Change ◽  
Wear Area ◽  
Railway Network ◽  
Operational Conditions ◽  
Rolling Surface ◽  
Test Loop ◽  
The Impact

The monitoring of railway rails damage on the railway network of the JSC “Russian Railways” as well as operational and polygon tests are conducted with the purpose of assessing the impact of operating conditions on the intensity of rails damage, obtaining initial data for forecasting rails failures. The increased intensity of rails wear on sites with a complex plan and profile leads to the fact that with a continuous change from the track, rails which have an underutilized service life of more than 20 % are retrieved. Polygon tests on the Test Loop of the JSC “VNIIZhT” near the Scherbinka station can provide the repeatability and reliability of the results, comparative tests are carried out under identical conditions and their duration is several times less than when tested at experimental sites under operational conditions. The results of the polygon tests of new differentially heat-strengthened rails did not reveal any advantages in the wear resistance of special purposed rails (laid in the recommended radius of the curve for its application) when comparing the rails of domestic manufacturers. Metal shelling out on the rolling surface of rails is the main reason for the removal of rails from test batches. The origin and development of defects of this kind is due to both violations of the technology of manufacturing rails, and because of violations of the current maintenance of the track. The metal stock in the area of the rail head of R65 type due to the increase in its dimensions positively affects the extension of the lifetime of the rails, reducing the cost of the life cycle and the rail itself, and the design of the track as a whole. When carrying out a separate study in order to obtain results characterizing the stability of high-quality rails to contact fatigue damage, it is advisable to optimize the conditions of the polygon tests, bringing them closer to operational ones. When forming the test results, it is necessary to expand the list of criteria for assessing the wear resistance of rails, supplementing it with the size of the wear area at the time of a certain operating time of the tonnage, with the introduction of this criterion into the appropriate methods for the polygon (operational) tests.

scholarly journals Effect of impact energy on wear behavior of high chromium white iron produced by liquid die forging

2018 ◽  
Vol 207 ◽  
pp. 03011
Author(s):  
B Qiu ◽  
S M Xing ◽  
Q Dong ◽  
H Liu
Keyword(s):  
Abrasive Wear ◽  
Impact Energy ◽  
Wear Behavior ◽  
Testing Machine ◽  
Wear Testing ◽  
Volume Loss ◽  
White Iron ◽  
High Chromium ◽  
Die Forging ◽  
The Impact

Impact abrasive wear behavior of high chromium white iron (HCWI) produced by liquid die forging process were investigated. the wear tests were performed with the MLD-10 abrasive wear testing machine, using SiO2 abrasive and with four impact energies of 1.5 J, 2.5 J, 3.5 J and 4.5 J for 120 min. The results indicated that the cumulative volume loss of HCWI sample increases with the growth of impact energy, and exhibits best wear resistance under low impact condition. For given impact energy, the volume loss increases with the increasing of wear time, which shown an approximately liner tendency. The macro-morphologies, SEM images of worn surface and cross-sectional images of wear samples were observed by optical microscope and SEM, and the wear mechanism and characteristics were analyzed. Results shown that the wear characteristics is mainly based on the shallow ploughing and accompanied by plastic deformation under lower impact energy, while the fatigue peeling and embedded abrasive become the most significant characteristics when the impact energy is higher.

Brush Seals Used in Steam Environments: Chronological Wear Development and the Impact of Different Seal Designs

2015 ◽  
Author(s):  
M. Raben ◽  
J. Friedrichs ◽  
J. Flegler ◽  
T. Helmis
Keyword(s):  
Abrasive Wear ◽  
Contact Force ◽  
Operating Conditions ◽  
Test Facility ◽  
Working Fluid ◽  
Two Stage ◽  
Blow Down ◽  
Frictional Contacts ◽  
Brush Seals ◽  
The Impact

During the last decades a large effort has been made to continuously improve turbomachine efficiency. Besides the optimization of the primary flow path, also the secondary flow losses have been reduced considerably, due to the use of more efficient seals. Brush seals, as a compliant contacting filament seal, have become an attractive alternative to conventional labyrinth seals in the field of aircraft engines as well as in stationary gas and steam turbines. The aim of today’s research related to brush seals is to understand the characteristics and their connections, in order to be able to make performance predictions, and to ensure the reliability over a defined operating period. It is known that inevitable frictional contacts lead to an abrasive wear on the rotor side as well as on the bristle side. The wear situation is essentially influenced by the resulting contact force at the seal-to-rotor interface during the operating time. This contact force depends on the seal’s blow down capability, which is mainly determined by the geometrical design of the bristle pack, e.g. the axial inclination of the investigated seal design, in combination with the design and material of the surrounding parts, as well as the thermal boundary conditions. For realistic investigations with representative circumferential velocities the TU Braunschweig operates a specially developed steam test rig which enables live steam investigations under varying operating conditions up to 50 bar and 450 °C. Wear measurements and the determination of seal performance characteristics, such as blow down and bristle stiffness, were enabled by an additional test facility using pressurized cold air up to 8 bar as working fluid. This paper presents the chronological wear development on both rotor and seal side, in a steam test lasting 25 days respectively 11 days. Interruptions after stationary and transient intervals were made in order to investigate the wear situation. Two different seal arrangements, a single tandem seal and a two-stage single seal arrangement, using different seal elements were considered. The results clearly show a continuous wear development and that the abrasive wear of the brush seal and rotor is mainly due to the transient test operation, particularly by enforced contacts during shaft excursions. Despite the increasing wear to the brushes, all seals have shown a functioning radial-adaptive behavior over the whole test duration with a sustained seal performance. Thereby, it could be shown that the two-stage arrangement displays a load shift during transients, leading to a balanced loading and unloading status for the two single brush seals. From load sharing and in comparison with the wear data of the tandem seal arrangement, it can be derived that the two-stage seal is less prone to wear. However, the tandem seal arrangement, bearing the higher pressure difference within one configuration, shows a superior sealing performance under constant load, i.e. under stationary conditions.

Resource calculation of weared equipment for electric trains of the ES2G series

2020 ◽  
pp. 43-50
Author(s):  
A. A. Vorob’ev ◽  
◽  
S.O. Zyazev ◽  
Keyword(s):  
Comparative Analysis ◽  
Wear Rate ◽  
Wear Surface ◽  
Mathematical Expectation ◽  
Operating Time ◽  
Operating Conditions ◽  
Wheel Pair ◽  
Rolling Surface ◽  
Flange Thickness ◽  
The Impact

The article discusses the impact of operating conditions on the wear of the wheels for ES2G electric trains. Thanks to the information on the controlled parameters of the wheel pairs (rolling, flange thickness and rim diameter) of ES2G electric trains operated by the MCC (Moscow Central Circle ) and the Oktyabrskaya Railway, a comparative analysis of the wear surface intensities of the rolling surfaces for seamless-rolled wheelsets has been performed. The analysis of the dependences of the mathematical expectation for the controlled parameter on the operating time showed that the wear rate of the rim for the electric trains operated by the MCC is 2,9 % higher than by the Oktyabrskaya Railway. Similar results were obtained for milling bar (2,33 % ) and the ridge thickness (24,3). Based on the results , it was concluded that the wheelsets wear of the ES2G series electric trains differs significantly in the two compared sections of circulation. Electric trains serving the Oktyabrsky direction has the intensity wheel pair wear lower than the trains serving the MCC. This will allow more time before turning to restore the profile of the rolling surface. The estimated value for the durability indicator of 90 % of the resource before changing the wheel pairs for the maximum wear of the rim is 2 million km at the MCC and 4.4 million km at the Oktyabrskaya Railway.

Analysis of Degradation Mechanisms of Gate Dielectrics Based on SiO2 in MOS Transistors

2020 ◽  
Vol 25 (6) ◽  
pp. 517-524
Author(s):  
D.A. Eliseeva ◽  
◽  
S.O. Safonov ◽  
◽  
Keyword(s):  
Mathematical Models ◽  
Gate Dielectric ◽  
Gate Dielectrics ◽  
Degradation Mechanism ◽  
Operating Time ◽  
Operating Conditions ◽  
Hole Injection ◽  
Operating Voltage ◽  
Mos Transistors ◽  
The Impact

Nowadays, the developed mathematical models, describing the degradation mechanism of the gate dielectric, permit to determine the value of the operating time to failure of a device depending on its internal properties and operating conditions. These models significantly reduce the time and material required for performing testing and processing of large amounts of experimental data. In the paper the gate dielectric gates based on SiO in n -and p -channel MOS transistors have been studied. It has been found that under the impact of the electric field the degradation of the gate dielectric with 5.3 nm thickness most likely occurs according to the thermochemical model ( E -model) and in case with 7 nm thickness dielectric- in accordance with the anode hole injection model (1/ E -model). The coefficients have been calculated and the analysis of the mathematical models, permitting to determine the service life gate dielectrics based on SiO with 7 nm thickness in n - and p -channel MOS transistors for different values, of their area, operating voltage and temperature, has been performed. This study can serve as a method for monitoring and determining the quality of the gate dielectrics of manufactured MOS transistors.

scholarly journals Model of Supplying Equipment System Based on the Assessment of the Residual Resource of Mining Drilling Rigs Components

2019 ◽  
Vol 105 ◽  
pp. 03006
Author(s):  
Fares Abu-Abed
Keyword(s):  
Simulation Model ◽  
Residual Life ◽  
Spare Parts ◽  
Operating Conditions ◽  
Drilling Process ◽  
Queuing Systems ◽  
Standard Values ◽  
Complex Mechanisms ◽  
Drilling Rigs ◽  
Equipment System

The structure of the rig includes many complex mechanisms -their wear, and the value of the residual life depending on it, directly depend on the operating conditions of the rig. In compliance with all the norms and technical conditions of drilling and the absence of abnormal situations in its process, all components must develop their resource, defined by technical conditions, after which they need to be replaced. When various types of complications and abnormal situations occur in the drilling process, the load on the drilling machinery mechanisms can increase dramatically, which does not necessarily lead to the drill failure, but it affects the residual life of those mechanisms and components, the loads that exceed the standard values. With subsequent occurrences of similar situations in the drilling process, this may lead to failure of the drill. The article presents the rationale for choosing a simulation model for organizing a system for supplying drilling rigs with spare parts and accessories based on the theory of queuing systems. The work is an integral part of previously published developments presented in the materials of articles in 2-nd and 3-rd International innovative mining symposiums (2017-2018).

scholarly journals Performance Analysis of a Solar Cooling System with Equal and Unequal Adsorption/Desorption Operating Time

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6749
Author(s):  
Farkad A. Lattieff ◽  
Mohammed A. Atiya ◽  
Jasim M. Mahdi ◽  
Hasan Sh. Majdi ◽  
Pouyan Talebizadehsardari ◽  
...  
Keyword(s):  
Cooling System ◽  
Operating Time ◽  
Operating Conditions ◽  
Solar Cooling ◽  
Overall Heat Transfer Coefficient ◽  
Experimental Findings ◽  
Solar Cooling System ◽  
Adsorption Desorption ◽  
The Impact ◽  
Adsorption Systems

In solar-thermal adsorption/desorption processes, it is not always possible to preserve equal operating times for the adsorption/desorption modes due to the fluctuating supply nature of the source which largely affects the system’s operating conditions. This paper seeks to examine the impact of adopting unequal adsorption/desorption times on the entire cooling performance of solar adsorption systems. A cooling system with silica gel–water as adsorbent-adsorbate pair has been built and tested under the climatic condition of Iraq. A mathematical model has been established to predict the system performance, and the results are successfully validated via the experimental findings. The results show that, the system can be operational at the unequal adsorption/desorption times. The performance of the system with equal time is almost twice that of the unequal one. The roles of adsorption velocity, adsorption capacity, overall heat transfer coefficient, and the performance of the cooling system are also evaluated.

Dynamics of Single-Hit Pneumatic Test Drill for Pulse-Shaping Analysis of Impacting Waves

2013 ◽  
Author(s):  
Jori Montonen ◽  
Erno Keskinen ◽  
Michel Cotsaftis ◽  
Juha Miettinen ◽  
Wolfgang Seeman
Keyword(s):  
Penetration Depth ◽  
Impact Energy ◽  
Pulse Shape ◽  
Model Updating ◽  
Blast Hole ◽  
Initial Pressure ◽  
Design Parameters ◽  
Drilling Process ◽  
Rod System ◽  
The Impact

Rock drilling is one of the elementary processes in mining industry. As larger diameter holes are drilled by hitting with units attached to the crone adapter down in the hole, the smaller blast holes are hit with units impacting the rod neck at rock surface. Key question in the performance and energy efficiency of the blast-hole drilling process is then, how completely the impact energy can be transmitted to the crone over the relatively long wave guide. There have been discussions about the effect of wave length and shape on to the penetration dynamics of rock drills. As the drilling process is a continuous set of hits following each other at relatively high constant period and the response is a random overlapped mixture of coming waves and returning reflected waves from multiple delayed hits, a detailed analysis of penetration dynamics is rather a complex problem. To overcome this difficulty, a full-scale half-manual test-drill has been designed and built to produce single hits for a systematic production and analysis of optimally shaped stress waves. The test-drill is an air-powered pneumatic gun, whose impact energy can be adjusted by setting the initial pressure level to correspond the desired end velocity of the piston. The design parameters, by which the pulse shape can be modified, are the length and the geometric profile of the piston body. The first problem to be faced is then to determine the optimal pulse shape for maximized penetration depth and the second one is to produce such desired shape by an optimal choice of the design parameters. The rig has been modelled using finite elements for the rod system and adiabatic state equations for the compressed and expanding air volumes. By modifying the design parameters, different penetration responses can be produced. In the first step, the model has been updated by means of experimental response measurements. The second step has been to modify the geometrical profiles of the piston body by starting from piece-vice linear and parabolic cross-sectional distributions. The output of the numerical analysis is to evaluate the penetration depth pro hit for different geometrical profiles. The most promising geometry has then been selected for the fabrication of the prototype piston. An experimental hitting test then completes the analysis, whose repeatability showed to be limited due to the random variation of the rock properties in the test bed. Test results obtained by using more regular concrete specimens exhibited reduced deviations in the responses, but the weakness in the test is the different damaging mechanism during the penetration. Another option is the use of an artificial load-sensing endsupport in order to produce a known boundary condition to replace the tool-rock resistance in the model-updating phase.

Microstructural Evolution and Wear Behavior Involving the K-Carbides Precipitation of a Fe-25Mn-6.6Al-1.3C Austenitic Steel

2018 ◽  
Vol 941 ◽  
pp. 668-673 ◽  
Author(s):  
Yi Fan Feng ◽  
Ren Bo Song ◽  
Zhong Zheng Pei ◽  
Lun Li
Keyword(s):  
Heat Treatment ◽  
Abrasive Wear ◽  
Austenitic Steel ◽  
Microstructural Evolution ◽  
Abrasion Resistance ◽  
Testing Machine ◽  
Solution Treatment ◽  
Aging Treatment ◽  
Wear Testing ◽  
The Impact

In this paper, the microstructural evolution and mechanical properties of the as-cast Fe-25Mn-7Al-1.3C austenitic steel after different heat treatment were investigated. After solution treatment and subsequent aging treatment, the κ-carbides with perovskite structure were found to precipitate coherently within the austenite matrix, which improved the initial hardness and mechanical strength. The experimental steel exhibited an optimal comprehensive performance after being solution treated at 1050 °C for 1 h and then aged at 550 oC for 2 h. The tensile strength was 751 MPa, the yield strength was 581 MPa, the elongation was 48%, the hardness was 252 HB, and the Charpy V-notch impact toughness was 168 J, respectively. The impact wear test was carried out on MLD-10 abrasive wear testing machine, and the worn out surfaces under different heat treatment were characterized by scanning electron microscopy (SEM). The results indicated that the abrasion resistance of the steel under the additional aging treatment was better than that of the as-solutionized steel. The optimal abrasion resistance was obtained after being soluted at 1050 °C for 1 h and then aged at 550 oC for 2 h. However, with the aging time increasing, the coarse κ-carbides precipitating around the grain boundaries would deteriorate toughness, which lead to increase of the abrasive wear volume loss. Besides, obvious micro-cracking and relatively larger peeling pit were observed.

scholarly journals Drill bit state-oriented drilling process classification with time-series data for wheeled drilling rigs

2021 ◽  
Vol 942 (1) ◽  
pp. 012010
Author(s):  
Bartłomiej Ziętek ◽  
Jacek Wodecki ◽  
Anna Michalak ◽  
Pawel Śliwiński
Keyword(s):  
Time Series Data ◽  
Pressure Level ◽  
Series Data ◽  
Measurement Unit ◽  
Hole Drilling ◽  
Drilling Process ◽  
Drill Bit ◽  
Feed Pressure ◽  
Drilling Rigs ◽  
Process Classification

Abstract This paper represents an analysis of the wheeled drilling rig’s drilling process. Thanks to data from the onboard measurement unit of the machine, the characteristics of the drilling process regarding state of the drill bit are identified and calculated. The aim of the work is to provide a comparison between different drill qualities and process classification using Threshold-based segmentation with feed pressure levels and duration of single hole drilling. Second methodology is hierarchical clustering to create cluster analysis. Thanks to these approaches, it is possible to detect the time when the drill bit should be changed. The obtained results state that the average drill time for a new drill bit is shorter approximately by 50% than for the worn-out bit in terms of average drilling duration. Moreover, these changes are visible in the subsystem pressure level of the machine under specific drilling regimes.

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