Methods for determining the bearing capacity and extreme pressure properties of lubricants used in heavy-loaded tribodynamic couplings of metallurgical machines and units

To solve contact problems related to the study of the interaction between a lubricated or non-lubricated friction pair, we used standard equipment - friction machines and tribometers. However, the use of factory-made research equipment does not always allow us to accurately answer the questions concerning the tribotechnical characteristics of friction and wear processes under specific operating conditions. A review of the literature on the technical capabilities of testing machines showed that their main drawback is the inability to programmatically set the modes of acceleration of the tribological system and tracking slippage in real-time. The study revealed the need to develop a methodology for investigating the extreme pressure properties of liquid lubricants in the tribocoupling acceleration mode, which is caused primarily by the effect of high contact loads acting in the contact areas of friction pairs, e.g. gears, rolling bearings, etc. when technological machines and equipment start and reach the operating speed. The paper considers a modernized friction machine capable of programmatically setting acceleration modes and investigating tribodynamic processes of lubricated frictional couplings. We developed a technique that makes it possible to evaluate the efficiency of a liquid lubricant during acceleration and its effect on the wear of a lubricated contact based on the use of the modernized friction machine.

TO ESTIMATE AND PREDICT TRIBOTECHNICAL PARAMETERS OF FRICTION PAIRS FROM SINTERED POWDER FRICTION MATERIAL WITH DIFFERENT STEEL COUNTERFACES FOR DISK FRICTION DEVICE

Approximating dependencies of tribotechnical parameters of friction pairs sintered powder friction material and different steel counterfaces of disk friction device on sliding speeds, obtained by results of tests on friction machine and intended for selection of materials of friction pairs, are given.

Leveling Out the Effect of Sample Runouts on Wear when Testing on the SMT-1 Friction Machine

The research is aimed at improving the quality of testing the tribotechnical characteristics of materials on the SMT-1 friction machine. Testing the bearing materials according to the disc-pad model may be incorrect due to sample runouts. The aim of this work was to level out the influence of sample runouts on wear and other tribotechnical characteristics of friction units.

OPTIMIZATION OF THE MINERAL COMPOSITION OF FRICTION GEOMODIFIERS

The article considers the rationale for the optimal mineral composition of friction geomodifiers for improving the tribological properties of friction surfaces. The practice of maintenance and repair of automotive equipment can be significantly supplemented by non-traditional tribotechnics for the non-selective restoration of worn-out friction interfaces and prevention of new equipment. The use of friction geomodifiers as an additive to lubricants dramatically changes the friction conditions. (Research purpose) The research purpose is in developing a methodology for selecting the optimal mineral composition for friction geomodifiers to the technologies of maintenance and repair of machinery and equipment. (Materials and methods) The article describes a study of 27 minerals for tribo-compositions using the ii5018 friction machine using the traditional method. (Results and discussion) A statistical analysis of the results of tribo-tests of different mineral compositions was performed to assess the effect of the petrocomposition on the effectiveness of friction geomodifiers...

Friction and wear tester

A compact and simple in design device (friction machine) for testing materials for friction and wear is developed. The device is intended for determination of the wear resistance and friction coefficient of structural, frictional and antifriction materials, as well as the tribological characteristics of lubricants. The measurement system of the device includes spring helical and flat spiral elastic elements, combined in one node and designed to measure the normal force and friction torque, respectively. Metal-cutting machines can be used as an external drive of the device. The friction machine was tested when measuring the wear rate and the value of the friction coefficient of the samples of cast iron SCh20, brass L63, technical aluminum A7, as well as modified aluminum A7 with improved mechanical characteristics. The materials were tested in tandem with a counter-sample made of hardened steel 95Kh18 according to the ball-ring scheme in dry friction mode and in boundary lubrication mode using I-20A industrial oil at a normal load of 50 N and a linear velocity in the contact zone of 0.5 m/sec. The wear degree was estimated by the weight loss. The obtained results are characterized by the sufficient accuracy and reproducibility. A severe wear of brass is observed at a given testing load. Tests of the aluminum samples modified with ultrafine diamond-graphite powder UDP-AG obtained from explosives showed an increase in the tribological characteristics by 10 – 18%.

A TECHNIQUE FOR MONITORING THE INTEGRITY OF THE COATING AND DEVICE FOR ITS IMPLEMENTATION

The developed methodology for monitoring the integrity of the protective coating is designed to control dielectric and high-resistance coatings. The control technique consists in measuring the resistance of the signal conductor located between the base of the part that is dielectric insulated from each other and the protective coating. By changing the resistance of the signal conductor, the integrity of the protective coating is judged. A friction machine that implements this technique allows testing the wear resistance of a coating according to GOST 30480–97 with simultaneous monitoring of coating integrity. The results of a joint test of a friction machine and methods during testing for wear of different coatinges are also demonstrated.

A machine for real-time estimation of the tribological characteristics of materials

A reciprocating friction machine Tribal-T intended for automated quality control of the rubbing surfaces of tribopairs is described. The distinctive feature of the machine consists in implementation of the forced relative motion due to the frictional interaction of the rubbing surfaces fixed on the drive and conjugate platforms. Continuous processing of the signals from displacement sensors is carried out under conditions of continuous recording of mutual displacements of loaded tribopairs using classical approaches of the theory of automatic control to identify the tribological characteristics. The machine provides consistent visual real time monitoring of the parameters. The MATLAB based computer technologies are actively used in data processing. The calculated tribological characteristics of materials, i.e., the dynamic friction coefficient, damping coefficient and measure of the surface roughness, are presented. The tests revealed that a Tribal-T reciprocating friction machine is effective for real-time study of the aforementioned tribological characteristics of materials and can be used for monitoring of the condition of tribo-nodes of machines and mechanisms.