HIGH STRENGTH C/V GRAPHITE CAST IRON MATERIAL FOR MAIN CONTROL VALVE HOUSING

摘要

The present invention relates to a mono-block high strength C/V graphite cast iron material for a main control valve housing, which improves mechanic performance and strength of a conventional C/V graphite cast iron material for a main control valve housing, as demands for increasing the pressure, performance, and durability of a main control valve are increased. In particular, the C/V graphite cast iron material comprises: 3.5-3.70 wt% of C; 2.30-2.60 wt% of Si; 0.3 wt% or less of Mn; 0.030 wt% or less of P; 0.02 wt% or less of S; 0.6-0.9 wt% of Cu; 0.003-0.005 wt% of Bi; 0.018-0.025 wt% of Mg; and the balance consisting of Fe and other inevitable impurities. Here, a configuration factor of the C/V graphite ranges between 0.2 and 0.55. A matrix structure thereof has a matrix structure phase in which perlite and ferrite coexist, wherein a percentage of the perlite in the matrix structure is 50-80%. Therefore, the present invention has a higher strength (50-60kgf/mm^2) compared to a conventional grey cast iron material. Furthermore, the occurrence rate of a contraction defect is decreased compared to a spheroidal graphite cast iron material. Resultantly, the present invention provides excellent castability and high measurement precision.;COPYRIGHT KIPO 2019