Tribological Study of Chisel Knives in Sandy Soil

Abstract

This paper presents the interaction system within the mechanical soil processing process, consisting of two large elements, the metal of the tool and the soil. Due to the two main forces acting on the chisel knives—friction and impact with the sandy soil—the wear of these chisel knives was determined. To determine the wear, a stand was used which allowed testing chisel-type knives in laboratory conditions by changing their functional parameters: working depth, angle of the knives to work the soil, working speed, humidity and granulation of the test environment. The present paper presents an application of the Archard-type wear law to the contact between a chisel-type knife and sandy soil (wet and dry sand). The theoretical model regarding the Archard wear coefficient considered three forms of surface damage (shake down, ratcheting and micro-cutting). The sand was considered spherical and rigid and the surface of the knife was flat. The experimental model considered real steel knives with different surface hardness and operation under controlled conditions of sand granulation, humidity, attack angle, depth of penetration and speed of sliding. The theoretical and experimental results highlight the wear behavior of chisel knives (Archard coefficient) in wet and dry sand.