Abrasive wear resistance of surface coatings on an excavating tip against a rock mass

Abstract

Abstract To study the possibility of increasing the wear life of ripper tips, several laboratory and field tests were executed to clarify the wear characteristics of the parent metal of the tip, and of sprayed or welded metal surface coatings. In general, the amount of wear of a metal specimen in the dry state is higher than when the tip is submerged in water. The relation between amount of wear of a metal specimen and contact pressure is expressed as an exponential function. For the parent metal and some surface coatings, the amount of wear increases rapidly with contact pressure due to a state of red heat and partial melting under high contact pressure. Among surface coatings, the welded metal of carbide composites shows the greatest wear resistance due to its highest initial hardness, to its resistance to softening by tempering, and to the high hardness and melting temperature of carbide composite grains containing vanadium, niobium, and tungsten. Also, a tip coated with welded metal maintains excellent ripping capability as the pointed end of the tip holds a sharp shape while it wears.