The influence of mechanochemically produced modifiers on the properties of cast iron at out-of-furnace modification has been studied. Short-term treatment in mechanochemical activators makes it possible to produce composite modifiers, which are wetted with iron melts, are uniformly distributed therein and effectively influence the crystallization processes. The effect of a modifier based on silicon carbide and chromium (as a protector metal) on the physical-mechanical properties of gray cast-iron and cast-iron with spheroidal graphite is considered. The introduction of SiC in the amount of 0.01-0.1 wt.% into gray cast iron causes the formation of mainly perlitic structure and, as a consequence, an increase in strength, hardness and wear resistance. For SiC content 0.1 wt.%, the tensile strength of GG-15 samples increased by 22.7%, GG-25 by 8%. The maximal increase in the hardness is observed for SiC concentration: for GG-15 – 0.1, for GG-25 – 0.01 wt.%. The GG-25 sample with 0.1 wt.% SiC exhibited the highest wear resistance. The introduction of SiC (0.01 – 0.1 wt.%) into cast iron with spheroidal graphite causes an increase in ferrite content, which promotes a substantial increase in impact viscosity and wear resistance (the highest wear resistance is observed with the introduction of 0.05 wt.% SiC).
Influence of Steel Scrap on Microstructure and Mechanical Properties of Spheroidal Graphite Cast Iron
