Research of the kinetics of thickness of the boundary layers of lubricating materials applied to drilling technology

2021 ◽  
pp. 115-120
Author(s):  
R.A. Ismakov ◽  
◽  
V.G. Konesev ◽  
F.N. Yangirov ◽  
G.L. Gaymaletdinova ◽  
...  
Keyword(s):  
Service Life ◽  
Boundary Layers ◽  
Friction Pair ◽  
Roller Bearing ◽  
Equipment Safety ◽  
Efficiency And Effectiveness ◽  
Drilling Technology ◽  
Resource Characteristics ◽  
Friction Surfaces ◽  
Kinetics Of

Improving the operational properties of lubricants increases the service life of the mechanisms and increase the durability of rubbing joints, which has a positive effect on the indicators of technical and economic efficiency and equipment safety. Therefore, great attention in tribology is paid to the analysis of the state of friction units in technology and the assessment of their resource characteristics, which makes it possible to increase their service life. The research aim is to study the general provisions on lubricants and lubricants, as well as the features of the boundary layers formation on friction surfaces and the observed patterns. Calculations of the boundary layers thickness using lubricating reagents at different energetic loading of the friction pair were carried out as applied to the roller bearing of a roller cone bit in the medium of cylinder oil 52 and DPS grease. The proposed research methodology made it possible to in-crease the efficiency and effectiveness of the means development for improving the tribotech-nical properties of drilling lubricants.

Wear Problems of Slide-Friction Pair

2015 ◽  
Vol 220-221 ◽  
pp. 361-366
Author(s):  
Guntis Springis ◽  
Janis Rudzitis ◽  
Anita Avišāne ◽  
Maris Kumermanis ◽  
Jevgenijs Semjonovs ◽  
...  
Keyword(s):  
Service Life ◽  
Sliding Friction ◽  
Friction Pair ◽  
Calculation Model ◽  
Surface Geometry ◽  
Wear Process ◽  
Layer Material ◽  
Wear Calculation ◽  
Form Deviation ◽  
Friction Surfaces

A number of different mechanisms and devices may involve sliding-friction surfaces. The issues of service life and its prediction for the details of such surfaces have always been of particular importance. The article determines the most suitable wear calculation model that allows considering the set of parameters necessary for calculating slide-friction pair. The offered model is based on the application of the theories of several branches of sciences. Since the wear process is variable and many-sided, it is influenced by numerous different parameters, for example, surface geometry (roughness, waviness, form deviation, etc.), physical and mechanical conditions of the upper layer, material components, wear regime, wear temperature, etc.

Estimation of Service Life of Mechanical Engineering Components

2019 ◽  
Vol 799 ◽  
pp. 71-76
Author(s):  
Oskars Linins ◽  
Ernests Jansons ◽  
Armands Leitans ◽  
Irina Boiko ◽  
Janis Lungevics
Keyword(s):  
Service Life ◽  
Service Time ◽  
Surface Texture ◽  
Mechanical Engineering ◽  
Friction Pair ◽  
Theory Of Elasticity ◽  
New Approach ◽  
Material Fatigue ◽  
Texture Parameters ◽  
3D Surface Texture

The paper is aimed to the methodology for estimation of service life of mechanical engineering components in the case of elastic-plastic contact of surfaces. Well-known calculation methods depending on physics, theory of probability, the analysis of friction pair’ shape and fit include a number of parameters that are difficult or even impossible to be technologically controlled in the manufacturing of mechanical engineering components. The new approach for wear rate estimation using surface texture parameters as well as physical-mechanical properties and geometric parameters of components is proposed. The theoretical part of the calculations is based on the 3D surface texture principles, the basics of material fatigue theory, the theory of elasticity and the contact mechanics of surfaces. It is possible to calculate the service time of the machine, but the process of running-in of the components is relatively short (less than 5%), therefore, the service time is mainly determined by a normal operating period, which also was used to evaluate this period. The calculated input parameters are technologically and metrologically available and new method for calculating the service time can be used in the design process of the equipment. The results of approbation of the method for estimation service time of mechanical engineering, which prove the applicability of mentioned method, are offered as well.

scholarly journals EVALUATION OF THE RESOURCE CHARACTERISTICS OF POLYCRYSTALLINE STRUCTURAL ALLOYS UNDER CYCLIC THERMOMECHANICAL LOADING

2021 ◽  
Vol 83 (4) ◽  
pp. 481-504
Author(s):  
I.A, Volkov ◽  
L.A. Igumnov ◽  
D.N. Shishulin ◽  
A.A. Belov
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Mechanical Characteristics ◽  
Stress Deviator ◽  
Thermomechanical Loading ◽  
Effective Stresses ◽  
Accumulation Of Damage ◽  
Resource Characteristics ◽  
Kinetics Of ◽  
Physical And Mechanical Characteristics

The main physical regularities of complex thermoviscoplastic deformation and accumulation of damage in structural materials (metals and their alloys) under various modes of cyclic combined thermomechanical loading and mathematical models of these processes are considered. A mathematical model of the mechanics of a damaged medium has been developed, which makes it possible to simulate the cyclic viscoelastoplastic behavior and determine the resource characteristics of polycrystalline structural alloys under the combined action of degradation mechanisms that combine material fatigue and creep. The model is based on the joint integration of equations describing the kinetics of the stress-strain state and damage accumulation processes. The final relation to the model is the strength criterion, the fulfillment of which corresponds to the formation of a macrocrack. The plasticity equations are based on the basic principles of the flow theory. To describe the creep process in the stress space, a family of equipotential creep surfaces of the corresponding radius and having a common center is introduced. The relationship between the creep equations and the thermoplasticity equations describing “instantaneous” plastic deformations is carried out at the loading stage through the stress deviator and the corresponding algorithm for determining and at the loading stage by means of certain relationships between “temporary” and “instantaneous” scalar and tensor quantities. At the stage of development of damage scattered throughout the volume, the effect of damage on the physical and mechanical characteristics of the material is observed. This influence can be taken into account by introducing effective stresses. In the general case, stresses, plastic strains, and creep strains are determined by integrating the thermal creep equations by the four-point Runge-Kutta method with correction of the stress deviator and subsequent determination of stresses according to the thermoplasticity equations, taking into account the average creep strain rate at a new time. The relationships that simulate the accumulation of damage are based on the energy approach to determining the resource characteristics. The kinetics of fatigue damage accumulation is based on the introduction of a scalar parameter of damage to a structural material and a unified model form for representing the degradation mechanism under fatigue and creep conditions. The influence of scattered damage on the physical and mechanical characteristics of the material is taken into account by introducing effective stresses. The results of numerical simulation of cyclic thermoplastic deformation and accumulation of fatigue damage in heat-resistant alloys (Haynes188) under combined thermomechanical loading are presented. Particular attention is paid to the issues of modeling the processes of cyclic thermoplastic deformation and the accumulation of fatigue damage for complex deformation processes accompanied by the rotation of the main areas of stress and strain tensors.

The Microstructure of 100CrMnSi6-4 Steel after Laser Hardening

2014 ◽  
Vol 604 ◽  
pp. 32-35
Author(s):  
Wojciech Napadłek
Keyword(s):  
Radiation Power ◽  
Friction Pair ◽  
Roller Bearing ◽  
Laser Hardening ◽  
Superficial Zone ◽  
Large Size ◽  
Micro Cracks ◽  
High Microhardness ◽  
Technological Opportunities ◽  
Geometric Surface

This paper presents analysis of the influence of the laser hardening bearing 100CrMnSi6-4 steel on the selected properties: hardness and microstructure. The best process parameters were selected by: radiation impulse length λ = 1064 nm, different radiation power density and repetition frequency, as well as different variants of geometric surface texture. The process was carried out in a air environment, mainly in the field of ablation texturing with "thermal effect." As a result of laser hardening, the obtained martensitic microcrystalline microstructure in the superficial zone and in the middle of the hardened zone, and martensitic - bainite and bainite in the transition zone. The microstructures with high microhardness in the range of 580 850 HV0.01 are resulting from ultrafast phase transformation occurring during the crystallization of the Fe-C-Cr-Mn-Si alloy from the liquid phase. The microstructures are in the area directly adjacent to the lubricant microchannels produced during laser texturing. It was clearly noticeable on highly fragmented microstructure and confirmed by increased microhardness. There were no micro-cracks on the surface layer, what promises great technological opportunities. The results are promising and may have a significant impact on improving the tribological associations friction pair: roller - large-size track roller bearing.

scholarly journals Technology to Increase Hydrocarbon Wear Resistance of Friction Units of Hydrogen Aggregates

2019 ◽  
Vol 297 ◽  
pp. 09001 ◽  
Author(s):  
Mikhail Shalygin ◽  
Sergei Kuznetsov
Keyword(s):  
Wear Resistance ◽  
Steel Surface ◽  
Friction Pair ◽  
Dehydration Process ◽  
Diffusion Capacity ◽  
Friction Units ◽  
Surface Irregularities ◽  
Friction Surfaces ◽  
Technological Methods ◽  
Wear Tests

The causes of hydrogen wear of the friction surfaces involved in hydrocarbon transfer and distillation processes are considered. Some technological methods for reducing the hydrogen wear of parts and friction units operating in hydrocarbon environment are given. A comprehensive technology for obtaining the properties of the surface layer is proposed, which provides an increase in the wear resistance of a friction pair and smoothing the surface roughness. The increase in wear resistance is based on several mechanisms: (1) decreasing biographical hydrogen due to the dehydration process; (2) smoothing surface irregularities by saturating the surface with silicon; (3) reducing the diffusion capacity of the steel surface caused by diffusion siliconizing; (4) reducing grain size of the material. Comparative wear tests were carried out, which showed the effectiveness of the proposed methods.

Power Loss of Slipper within Axial Piston Pump

2015 ◽  
Vol 779 ◽  
pp. 3-12
Author(s):  
Ze Bo Wang ◽  
Ji Hai Jiang ◽  
Yi Sun
Keyword(s):  
Power Loss ◽  
Friction Pair ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Factors Affecting ◽  
Friction Power ◽  
Swash Plate ◽  
Model Of Friction ◽  
Friction Surfaces ◽  
Axial Piston

The pair between slipper and swash-plate is an important friction pair in the axial piston pump. Due to quick relative velocity, alternating load, numerous slippers, and high contact pressure between the friction surfaces, the wear-out and fatigue failure constantly occurs, which is one of the key factors affecting reliability of the piston pump. It is of fundamental significance to investigate the mechanism of slipper power loss and to find an appropriate method to improve the lubrication of the slipper. Here, the model of friction power loss between slipper and swash-plate is established, and the friction power loss between slipper and swash-plate is solved and comparatively analysed. Finally, the correctness of theoretical analysis and simulation results are verified by experiments.

scholarly journals Justification of risk-based approach of operation of mobile agricultural equipment on example of details of separate units of tractors

2020 ◽  
Vol 11 (3) ◽  
pp. 173-179
Author(s):  
O. V. Voynalovich ◽  
◽  
S. M. Holopura ◽  
Keyword(s):  
Service Life ◽  
High Reliability ◽  
Limit State ◽  
Construction Materials ◽  
Flaw Detector ◽  
Agricultural Machinery ◽  
Acceptable Risk ◽  
Agricultural Equipment ◽  
Power Load ◽  
Kinetics Of

It is shown that in order to justify the extension of the service life of the machine beyond the resource set by the developers, it is necessary to focus on the allowable risks of accidents that can lead to accidents. After all, today for mobile agricultural machinery, the operation of which is associated with high-risk work, the concept of acceptable (acceptable) risk is not used, which does not allow to assess the danger of being on fields, farms and roads without machinery, with exhaustion of installed resources. The purpose of researches is to justify the permissible risk of exploitation of mobile agricultural machinery, in array of details and elements of constructions which have accumulated defects (damage). This paper analyzes the kinetics of accumulation of operational defects in the array of parts of individual components (systems) of tractors. MTZ-80 tractors (82) were chosen as the object of research, as one of the most common in Ukraine. To detect cracks, a developed eddy current flaw detector was used, the sensitivity of which allowed to find cracks several millimeters or larger in length without preparing the surface of the controlled parts. It is shown that the kinetic dependences of the accumulation of operational defects in the parts of tractor units in the analyzed range of service life are monotonically increasing, which can be described by exponential functions with a sufficiently high reliability. It is noted that the obtained dependences are similar to the kinetic dependences of the accumulation of static and dynamic (fatigue) damage obtained as a result of laboratory tests of samples of construction materials, which allows to use approaches to the criteria of the limit state of laboratory samples due to the power load to establish the boundary life of mobile agricultural machinery. However, the kinetics of the intensity of the occurrence of operational cracks in the array of tractor parts is not monotonous and has a maximum in the range of about 11-13 years of operation. This service life can be used as a criterion to stop the operation of the tractor, to carry out defectoscopy of parts and to replace defective parts. With such a long service life of the tractor, there is the greatest probability of sudden destruction of the tractor components and the creation of emergencies.

scholarly journals Improvement of the tribological properties of heavy-loaded friction units “Centre block-footstep bearing” of a freight car

2021 ◽  
Vol 2131 (5) ◽  
pp. 052033
Author(s):  
A Sychev ◽  
V Avilov ◽  
M Savenkova ◽  
E Luneva ◽  
A Sychev
Keyword(s):  
Service Life ◽  
Tribological Properties ◽  
Friction Unit ◽  
Inorganic Polymers ◽  
Adhesion Properties ◽  
Friction Units ◽  
Physical Chemical ◽  
Operational Tests ◽  
Freight Car ◽  
Friction Surfaces

Abstract Various problems and different approaches of solution of such a problematic unit as “centre block-footstep bearing” of freight cars are discussed in the paper. The methods of improving the tribological properties of this friction unit by means of material modification of friction surfaces and perfection of physical, chemical and tribological properties of the used lubricants were studied. Grease lubricants common for friction units of railway machinery were used after being modified with inorganic polymers based on double metaphosphates. Bench and operational tests of the developed additive of the polymeric double metaphosphates were carried out. This additive reduces wear and increases the service life of the friction unit, due to the better adhesion properties of this additive. The variants with a change in the geometry of the contact surface of the disk between the bolster and the “centre block-footstep bearing” arrangement of the car are considered. Simulation of the parameters of movement in curved sections is proposed.

Increasing the reliability of refrigerators used to produce green paste

2021 ◽  
pp. 48-53
Author(s):  
P. G. Krinitsin ◽  
A. G. Grinkevich ◽  
A. S. Yasinskiy
Keyword(s):  
Service Life ◽  
Thermal Effects ◽  
Corrosion Damage ◽  
Physical Parameters ◽  
High Alloy ◽  
High Alloy Steel ◽  
Metallic Structures ◽  
Steel Aisi ◽  
Oxidative Processes ◽  
Kinetics Of

The work is aimed at the oxidative processes occurring in the metallic structures of the universal refrigerators “UKHB 3/30” used to transport and cool calcined coke. The temperature of the coke entering the device reaches 1320 oC. As it moves along the device, chemical and thermal effects occur on unprotected metallic structures with the formation of erosion centers and through damage to the shells. The service life of refrigerators hot-cut metallic structures made of A284 Grade B (ASTM) is 1 year, which determines its repairs frequency. Experiments on the oxidative processes in real conditions of operation of refrigerators were conducted for samples made of carbon steel of the A284 Grade B (ASTM) brand and heat-resistant high-alloy steel AISI 301. Changes in the chemical composition and physical parameters were determined in the samples. The thermogravimetric method for estimating the corrosion kinetics based on the sample mass loss, spectrometric study of metal samples, and classical chemical “wet” analysis were used. According to the results, the degree of corrosion damage of samples after 1,5 hours is estimated. The kinetics of corrosion has been studied. The mechanism of decarburization of the surface layer in A284 Grade B (ASTM) steel and the accompanying deterioration of the metal mechanical properties are described. An economic analysis of the feasibility of using AISI 301 steel to increase the service life of refrigerators was carried out.

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