Effect of Copper and Chromium Addition on the Mechanical and Wear Resistance of Tempered Hypoeutectic Grey Cast Iron used in Crusher Applications

In brickyard industry, smooth roll crusher is the most critical component in the brick production process. The main damage to the surface of the roll crusher comes from abrasion wear. Grey cast iron with a CE around 4.0 was chosen for the manufacture of these rolls crushers. Castings with various compositions in the basic Class 25 grey cast iron were cast with the combined effects of copper and chromium to study their effects on their castability, mechanical properties and wear. The casting parts were heated to 900 degrees C and quenched with forced air. Optical metallography, chemical analyses, Brinell hardness and Vickers microhardness, tensile tests and wear tests were used to characterize the ingots cast. All the cast irons made were hypoeutectoid with a microstructure consisting mainly of class A type graphite in a pearlitic matrix. The sensitivity of cast iron to the mass effect has been greatly reduced by appropriate and economical additions of copper and chromium. Normalization treatment, high cooling rate through the eutectoid transformation temperature interval and additions of Cu and Cr promote the formation of a finer and harder pearlite. All these factors contribute to increase the strength and hardness of alloyed hypoeutectic grey cast iron. The results showed that the quenched and tempered alloys had best wear resistance at 400 degrees C for alloyed grey cast iron (containing 0.62%Mn, 0.37%Cr, 1.21% Cu and 0.12%Mo).