Технологія синтезу термітних антифрикційних чавунів

Abstract

Розроблено технологію синтезу термітних антифрикційних чавунів у результаті алюмінотермічних реакцій. Встановлено технологічні особливості синтезу. Досліджено хімічний склад отриманих антифрикційних матеріалів. Виявлено вплив температури на силу та коефіцієнт тертя, вплив швидкості обертання на коефіцієнт тертя та режими роботи пари тертя з термітних антифрикційних чавунів − аналогів за хімічним складом промисловим маркам АС4-1, АС4-2 та АВ4-1, АК4-1. Проведено порівняння службових властивостей різних матеріалів − бронзи, бабіту, антифрикційного чавуну.

Antifriction cast irons are used for production of different parts, which operate as friction pairs (e.g. bearings) in the presence of lubricants to prevent the contact of friction surfaces. Taking into account the fact that cast iron is in 3,3...18 times cheaper than other antifriction materials (except rubber) it can be well promising in use. From the antifriction theory point of view the properties of materials are considered mainly taking into account their interaction with the contacting surfaces. Therefore antifriction materials must provide: high enough durability; good breaking-in, high static and dynamic strength at high temperatures, good oil soakage and adhesion retaining of oil on the surface, high strength of the oil film on the surface of alloys, geometric structure of the surface, which should improve the retaining and feeding of oil on the area of friction. In the presented paper the combining of thermite antifriction cast iron advantages with metal thermal methods of their production is proposed. The advantages of metal thermal synthesis methods include: self-contained manufacturing process, independence of energy sources, simplicity of equipment, high-performance process, short time of synthesis and easy transition from experimental research to industrial production. All these resulted in the need to develop the proposed technology of synthesis the thermite antifriction cast irons caused by the aluminothermal reactions and establishment of manufacturing peculiarities of synthesis. At the first phase of the study the chemical composition of the synthesized antifriction cast irons АС4-1, АС4-2, АС4-3, АВ4-1, АК4-1 were found. Further the influence of temperature on the strength and the coefficient of friction, impact of velocity on the coefficient of friction of the thermite antifriction cast irons similar in their chemical composition to the industrial brands of antifriction cast alloys “AC4-1”, “AC4-2” and “AB4-1”, “AK4-1” have been found. The operations modes of friction pair components made of thermite antifriction cast iron were determined. Comparison of the operating properties of different types of materials, synthesized antifriction cast iron, bronze, babbit in particular, has been carried out.