Coefficient of mutual overlap in metal-polymer tribosystems

The polymer hybrid material under study is used as an antifriction coating of the friction contact surface. The experimental studies have been carried out on a special test bed with a reciprocating motion of the tribosystem in conditions of a mutual overlap coefficient less than one. The influence of the most important operational parameters, such as temperature, operating wear and wear rate, has been studied. The temperature was determined in the area of fixing the coating on a metal substrate, since the adhesive strength of the coating ensures the operability of this tribosystem. In addition, for the maximum friction modes, such standard parameters as the wear intensity and service life have been calculated. The wear resistance class has been set.

Increasing the life of the center plate-center bowl friction unit of a freight car by applying a combined coating formed by electrospark alloying

An increase in the operational reliability of friction units of railway transport by applying antifriction combined coatings formed by electrospark alloying, which ensures their greater strength and adhesion to metal, is considered. Keywords: electrospark alloying combined antifriction coating, strength, adhesion. [email protected]

INFLUENCE OF TECHNOLOGICAL FACTORSFOR THE QUALITY

The article contains a study of the influence of technological factors on the formation of a film antifriction coating when applied to parts of cars and cars. The article presents a methodology and results of calculating the adhesion strength of a film coating with a steel base. The equipment used to determine the adhesion strength is presented. The technique of using the specified equipment is described. The dependence of the adhesion strength on the modes of film coating is established and described. Recommendations have been developed for the selection and method of applying film antifriction coatings during the maintenance and repair of motor vehicles.

Study of operational properties of steel friction pairs with antifriction coating from copper alloys produced by electric spark alloying

Improving the reliability, durability and safety of operation of heavily loaded friction units is an urgent problem in physics, chemistry and surface mechanics. The tribotechnical characteristics of coatings made of bronzes BrAZhMts10-3-1.5 and BrMtsF3-6, applied by electrospark alloying on bushings made of structural steel 30KhGSN2A for operation under conditions of high contact pressure under friction without lubrication, have been investigated. Modes of coating deposition from the standpoint of tribology (the value of the electric discharge current in a pulse, the value of the longitudinal electrode feed per one rotation of the part, the rotation speed of the workpiece, the number of passes during processing, finishing of the coating) have been developed. It was found that when applying bronze BrMtsF3-6 to obtain a high-quality coating, the process must be performed in a protective atmosphere of argon to prevent phosphorus burnout. The tribotechnical efficiency of coatings when working under dry friction conditions is shown. For the steady-state wear mode, the friction coefficient is 0.10 – 0.13 at a pressure of 200 – 250 MPa, the wear resistance of coated steel is doubled. Steel with a bronze coating BrAZhMts10-3-1.5 has a higher bearing capacity, with BrMtsF3-6 coating — a higher antifriction. The ways of increasing the service life of steel-coated steel friction pair are analyzed.

Repair technologies using polyamides

A new method is proposed and equipment is developed for applying a polyamide antifriction coating to worn surfaces of parts. Its use with a machine tool with NC implements the principle of additive technology. The composition of the polyamide composition was selected for the restoration of permanent joints, which ensure their protection against fretting corrosion and the required strength. Keywords: polyamide coating, additive technology, fretting corrosion, inner surface, modification. [email protected]

COMPARATIVE ANALYSIS OF METHODS FOR STUDYING THE ADHESION OF ANTIFRICTION COATINGS FOR FRICTION UNITS OF AUTOMOTIVE TECHNOLOGY AND TECHNOLOGICAL MACHINES

The article presents a study of the adhesive strength of adhesion of thin solid antifriction coatings. A brief analysis of existing methods for determining the adhesive strength of thin anti-friction coatings is performed. The method is described and experiments are carried out using a universal-purpose breaking machine with an electronic force meter IR5047-50 and a portable ad-hesive meter of the «Constant A» model. A number of quantitative estimates of the adhesion strength of the antifriction coating with the base are obtained. Conclusions are made about the adhesion strength of the coating and methods for determining its adhesion. Recommendations on the application of methods for determining the adhesive strength of thin solid antifriction coatings are given.

INFLUENCE OF FORCE OF INERTIA ON COATING CLUTCH WITH EXTERNAL SURFACE OF ROTATION BODIES WHEN COATING

A paper is dedicated to the investigation of inertia impact upon coating adherence with the outer surface of revolution solids during coating application. The work purpose is a qualitative and qualitative assessment of factors of antifriction coating application affecting the parts of friction units of machines and units. The relevance is substantiated with that the strength increase of coating applied ensures life, reliability and power effectiveness of machines and mechanisms. The work novelty consists in the application of fundamental dependences and laws to actual manufacturing operations. Adhesion is a basic parameter charactering quality of the coating applied. Adhesion, in its turn, is characterized with adhesion strength and porosity of the coating applied. The material presented shows the impact of inertia acting upon particles of the coating applied at their falling on the outer surface of rotation. There are defined theoretical dependences describing the process mentioned. The analysis of these dependences shows that inertia can carry out both the positive and negative action during the application of antifriction coatings. To confirm the theoretical results obtained there were carried out experimental investigations. In the experiment took part some sets of samples upon which PRNH17SR4 antifriction coating was applied. Coating application was carried out with the aid of the Iskra-1 burner with the further fusing. For the qualitative and quantitative strength assessment of adhesion of the coating applied there was used a method for a shear test. The samples prepared were pressed through a matrix on the GMS-50 universal rupture-test machine. As a result of tests carried out there are obtained dependences characterizing adhesion of antifriction coating applied. The dependences obtained show efficient factors impacting the adhesion strength of coatings. By the results of theoretical and experimental investigations there are formulated qualitative and quantitative assessments of factors influencing the process of antifriction coating application on parts.

Modeling and research of the process of preparing the surface of a part for thermal spray coating

The article presents an analysis of ways to increase the adhesive strength of antifriction coating. A rational method for the mechanical formation of surfaces is proposed. The calculation of the workpiece based on the finite element method has been carried out. The theoretical dependences of metal lifting on the depth of the rolling roller are obtained. The results of a field experiment are presented. A comparative analysis of theoretical and practical results of the research has been carried out. Recommendations are given for the further use of the net rolling method with a pre-cut “ragged thread”.