Evolution of the Mechanical Properties of the Surface Layers of Aluminum Alloys under the Conditions of Sliding Friction

Mechanical properties of surface layers of aluminum alloys before and after friction tests are studied by nanoindentation. The influence of the composition of the alloys on these properties is analyzed. It is obtained that as a result of wear and tear, relatively compliant layer is formed on the surface of one of the alloys. Another sample demonstrates relatively rigid film at the surface of the friction path. Conclusions about different mechanisms of the wear and tear of alloys are made based on the analysis.

Influence of lubrication on the friction and wear of car rolling bearings

The goal of the work is to develop computational and experimental approaches to determine the wear resistance of friction units with internal contact of cylinders with slip. The scientific novelty consists in taking into account the slip for calculating the friction path and the wear of the cylinders with internal contact and the proposed method for identifying the parameters of the wear law based on the test results. Practical value is the proposed methods to account load, slip and lubrication conditions on the resource for the design of friction units. The dependences for determining the friction path for internal rolling of cylinders have been considered. The design of an experimental setup for studying friction and wear of cylinders with slip has been proposed. Experimental studies have been carried out: paths of friction; wear of surfaces both with a key and without a key; the effect of lubricants on wear has been studied. The form of the wear model is proposed to determine the effectiveness of methods for increasing wear resistance. The method for determining the parameters of the wear law has been implemented based on the test results. The results show the efficiency of copper powder as an additive to a lubricant. It has been established that the wear of cylinders with a key is greater than the wear of cylinders without a key due to different friction paths. A practical example of determining the wear of a car hub shaft using the wear patterns is presented.

Regression analysis of the influence of auger surface hardness on its wear during dehydration of solid waste in a garbage truck

The article is dedicated to the study of the influence of the surface hardness of the auger on its wear during dehydration of solid waste in the garbage truck. Using the method of regression analysis, the logarithmic dependencies of auger wear depending on the hardness of its surface for different values of the friction path are determined. Graphical dependences of augur wear depending on the hardness of its surface for different values of the friction path are made up, and it confirms sufficient convergence of the obtained dependencies. Carried out additional regression analysis allowed to obtain the dependence of wear of the auger depending on the hardness of its surface and the friction path, which showed that during two weeks of operation and wear of the auger during dehydration of solid waste in the garbage truck increasing the surface hardness of the auger from 2310 MPa to 10050 MPa reducing the rate of growth of energy consumption of solid waste dehydration from 16.7 % to 1.5 %, and, consequently, to reduce the cost of the process of their dehydration in the garbage truck. The graphical dependence of the reduction of energy consumption of dehydration of solid household waste due to the increase in the hardness of the auger surface during its two-week wear is presented. It was established the expediency of further research to determine the rational material of the auger and ways to increase its wear resistance

Assessment of wear resistance of hardened additive products made of electroerosive cobalt-chromium powder

Experimental studies of the wear resistance of hardened additive products made of electroerosive cobaltchromium powder obtained in alcohol are carried out. With a friction path of 500 m, the following was established: partial wear of the counterbody and adhesion of wear products of the sample to the counterbody; the size of the wear track of the sample; the depth of the profile of the wear groove of the sample surface; friction coefficient; wear of a counterbody made of steel and a hardened sample made of a cobalt-chromium alloy. Keywords: electroerosive cobalt-chromium powder, additive product, hardening, wear resistance. [email protected]

Investigation of the structure and properties of reinforced additive products obtained from electroerosive cobalt-chromium powder

The analysis of the wear resistance characteristics of samples sintered from high-chromium electroerosive powders obtained in kerosene on a friction path of 500 m is performed. It was established experimentally that: there is a partial wear of the counterbody and the buildup of the products of wear of the sample on centralo; the magnitude of the wear track of the sample is 383,1 µm to 473,5 mm; the depth of the profile grooves of the wear surface of the sample is 5 microns; the coefficient of friction of the surface of the sample is from 0,228 to 0,826; the wear rate of the counterbody made of Stainless Steel AISI 420 and the sample made of sintered steel 12X17 are 0.016 and 1.138, respectively.

Unifed indicator of the wear of plastics for different assessment methods

The possibility of describing the wear of plastics, determined according to international standards ISO 9352, ISO 4649, GOST 11012, DIN 52108, EN 295-3, using a unified wear indicator, which is the loss of the volume of the wear material per unit of friction path, has been studied. It is shown that different methods give close values of the unified indicator of wear resistance.

Tribotechnical characteristics of hard alloys in sliding friction units

The paper presents experimental data on the study of the friction parameters of hard alloys in sliding friction units, including the heating temperature, surface roughness, wear and friction coefficient, depending on the duration of the test and the friction path.

ANALYSIS OF CHARACTERISTICS OF WEAR RESISTANCE OF SINTERED ITEMS FROM ELECTROEROSION LEAD BRONZE OBTAINED IN KEROSIN LIGHT

The article presents the results of a study of the wear resistance of sintered samples of lead erosion bronze. Dispersed particles were obtained by electroerosive dispersion of BrS30 alloy waste in a carbon-containing medium - illuminating kerosene. Then, the obtained erosion materials were pressed using a Herzog TP 20 hand-held table press at a pressure of 1500 MPa and sintered in a Nabertherm GmbH RS 80/300/13 furnace for 2 hours at a temperature of 827 ° C in argon atmosphere. Then studied the surface roughness of the obtained samples, the friction coefficient and the wear factor of the samples. The friction coefficient and the wear rate of the surface of the samples and the counterbody were measured on an automated friction machine according to the standard ball-disk test scheme. The tests were carried out in air at a load of 2 N and a linear speed of 10 cm / sec, a radius of curvature of wear of 5-6 mm, the friction path was 200 meters. It was shown that the roughness by three measurements of the sample surface is Ra = 0.38 μm, the height of the profile irregularities at 10 points 𝑅𝑧 = 10.3. The arithmetic mean deviation of the profile of the sintered product corresponds to the 8th class of roughness of the parts. The height of the profile irregularities at 10 points corresponds to the 6th class of roughness of the parts. The friction coefficient was 0.395. The wear factor of the sample was 347x10 mm3Nm.

Analysis and Comparative Assessment of Basic Tribological Properties of Selected Polymer Composites

Phenomena occurring in the contact area between two mating bodies are characterised by high complexity and variability. Comparisons are usually made between parameters such as the coefficient of friction, friction force, wear and temperature in relation to time and friction path. Their correct measurement enables the proper evaluation of tribological properties of materials used in the friction pair. This paper concerns the measurements of basic tribological parameters in the friction of selected polymer composites. Knowing the tribological properties of these composite materials, it will be possible to create proper operating conditions for kinematic friction pairs. This study investigated the coefficients of friction, friction force and temperatures of six polymer composites: cast polyamide PA6 G with oil, PA6 G with MoS2, polyoxymethylene POM with aluminium, polyethylene terephthalate PET with polytetrafluoroethylene PTFE, PTFE with bronze, and PTFE with graphite. The friction surface was also examined using an optical system and computer software for 3D measurements. As a result, PA6-G with oil was found to be the best choice as a composite material for thin sliding coatings.

Analysis of the Influence of Blanking Clearance on the Wear of the Punch, the Change of the Burr Size and the Geometry of the Hook Blanked in the Hardened Steel Sheet

In this thesis, the results of an experimental analysis of blanking angled hooks with a punch of a sloping face in a thin steel sheet with a hardness of 55 HRC are presented. The blanking punch was made of K340 cold-work tool steel. Tests were carried out for three values of clearance, 5%, 10%, and 15% of sheet thickness. The results of the analysis of the influence of the number of cuts made by the punch on the growth of the burr at the sheet edge were presented. Moreover, the influences of the clearance on the initial values of burr (bh), deflection (Hb), and the bending radius (Rb) of the hook have been shown. The influence of the friction path on the intensity of degradation of working surfaces and the blanking edges of the punch was also demonstrated. The obtained results allow the selection of the proper clearance and new tool materials for blanking blades working in particularly difficult tribological conditions.