Heat Resistant Cast Irons have been used in high temperature environment, so it must have excellent high temperature properties, such as high temperature tensile strength, high temperature fatigue strength and thermal shock resistance. The objective of this study is to investigate the high temperature strength property and thermal shock resistance of the heat resistant cast irons. The effects of matrix structure (ferrite, pearlite and austenite), graphite morphology (flake, compacted I vermicular, spheroidal) and alloying element (Cr,Ni) on the high temperature tensile strength and thermal shock resistance at different temperatures(1073 K 873 K and 673 K) of cast irons have been evaluated in this study. According to the results of this study know that, as a whole, the order of high temperature tensile strength for alloying element is that 0.5%Cr>20%Ni-2%Cr>none alloy addition at R.T., 673K, and 873K; but the order is that 20%Ni-2%Cr>0.5%Cr>none alloy addition at 1073K. The order of high temperature tensile strength for the matrix structures is that pearlite>austenite>ferrite; but the order is that austenite>pearlite>ferrite at 1073K. The order of high temperature tensile strength for various graphite morphology is that spheroidal>c I v>flake at various test temperature. For thermal shock resistance of cast irons, the order of thermal shock resistance for graphite morphology of cast iron is that spheroidal>c I v>flake. The order of thermal shock resistance for matrix is austenite>pearlite>ferrite. The order of thermal shock resistance for alloying element is that 20%Ni-2%Cr-0.5%Cr>none alloy addition. Quality Index of High Temperature Strength Property (Q{sub}(HTSP)) is obtained for evaluating the high temperature property of the heat resistant cast iron by analysis and evaluation. It is showed has high accuracy and can be used as an important index and reference. We also derive the regression equation of thermal shock cycle to shape factor (Fs) and matrix factor (Fm) for the heat resistant cast iron at 1073K by regression analysis method.
Heat resistant cast iron 'high temperature strength' thermal shock resistance quality index