Influence of two-body abrasion and heat intensity on metal and non-metal materials used in agriculture

Abstract

Valášek P., Kejval J., Müller M., Cieslar J. (2015): Influence of two-body abrasion and heat intensity on metal and non-metal materials used in agriculture. Res. Agr. Eng., In the agro-complex, as well as in other sectors, the use of polymeric materials is one possible way forward in the innovation and development of machines and their parts. However, machine products place high demands on the materials from which they are made. Polymeric materials are currently able to compete in certain areas where metallic material would traditionally be used; however, one of their limiting characteristic is their ability to withstand elevated temperatures. This paper describes the hardness of polymeric materials when influenced by heat, generated during the double body abrasion. The paper also describes the abrasive wear of both polymers and polymeric composite systems, as well as cast iron, used in agricultural production. Heat intensity during the two-body abrasion results in a 28% fall of the composite systems hardness, to 18% fall of the Polyamid 6 hardness and to 13% fall of the Murtfeld hardness.Keywords: abrasive wear; composite systems, epoxy resin, polymers; temperature In recent years, industry has seen an increase in the production of plastic products in an attempt to replace the conventionally used metallic materials. One of these sectors is agriculture. The use of polymers have considerable advantages to the agricultural industry, they are easy to mould, resistant to corrosion and environmental deterioration. They have an ability to temper vibrations, low density and are cost-effective. In a specific application of various materials, particularly polymeric materials, it is necessary to consider the considerable dependence on temperature (Parry, Tabor 1973).Abrasive wear occurs when a specimen comes into contact with the abrasive material. The motion of the specimen on the abrasive material creates friction and part of this mechanical energy is converted into heat. The effects of heat at varying intensity can affect the characteristics and composition of many materials.Polymeric materials predominantly transfer heat through the vibratory motion of atoms while metallic materials transfer heat through the kinetic energy of electrons. It is for this reason that polymeric materials are usually of lower thermal conductivity, increasing temperatures create a downward effect on the yield strength of thermoplastic materials. This is evident, although not so obvious, in metallic materials. The prevailing characteristic of chemical bonds in polymeric materials results in their higher thermal expansion compared with metallic materials (Vojtěch 2010).