Computational Assessment of Thermal Conductivity of Compacted Graphite Cast Iron

Abstract

Two-dimensional FE models of CGI with different pearlite contents for thermal conductivity analysis were established according to the real metallographic images obtained by Pro/E and ANSYS. Meanwhile, thermal conductivity of CGI with different pearlite contents was tested through the laser flash method. It is indicated that the thermal conductivity of CGI declines with the increase of pearlite. When pearlite is increased from 10% to 80%, the experimental values decline from 46.63 W/m·K to 36.86 W/m·K, reducing by 21%. However, this declining tendency becomes gentle and slight when pearlite is more than 40%. In addition, the calculation results with the consideration of interfacial contact thermal conductance (ICTC) and pearlite are much close to experimental values; especially when pearlite is 80%, the difference between them is only about 2%. It can be concluded that the FE models are convenient and reasonable to analyze thermal conductivity of CGI.

A New Theoretical Method for Studying Effects of Microstructure on Effective Thermal Conductivity of Vermicular Graphite Cast Iron

“…The numerical simulation method can realize the control of a single microstructure variable. Previous studies, combining with experiments and 2-D or 3-D finite element analysis, reported the effects of vermicularity [ 18 ], pearlite content [ 19 ], interfacial contact thermal conductivity (ICTC) [ 20 ] and spatial connectivity [ 21 , 22 ] on the thermal conductivity of VGI, respectively. Nevertheless, finite element modeling of vermicular graphite is difficult considering graphite anisotropy.…”

“…Therefore, if several simplified graphite models with topological equivalence [ 31 , 32 ] are established according to the 2-D and 3-D morphological characteristics of three types of graphite and the ratio of the a-axis and c-axis, it is believed that the real vermicular graphite will be included. Finally, the effect of interface between graphite and matrix is not also negligible on thermal conductivity of VGI [ 19 , 20 ].…”

The damage mechanism of tension-tension fatigue interaction with creep damage of the compacted graphite cast iron alloy at high temperatures

“…The high power density (HPD) diesel engine is one of the advanced engines in the future. Compared with the traditional diesel engine, the volume and weight of HPD are reduced by more than 50%, but the rotation speed of the crankshaft and explosion pressure increase by 100% and 200%, respectively [1][2][3]. As an essential hightemperature component, the cylinder head made of compacted graphite cast iron (CGI) alloys is usually experiencing 400 °C-500 °C and 20-30 MPa explosion pressure [4][5][6].…”

Quantitative models for microstructure and thermal conductivity of vermicular graphite cast iron cylinder block based on cooling rate

“…Quantitative models for microstructure and thermal conductivity of vermicular graphite cast iron cylinder block based on cooling rate nonhomogeneous temperature distributions in service. Many researchers [8][9][10] have focused on the effects of microstructure including graphite morphology, graphite amount and pearlite fraction on thermal conductivity of cast iron. Matsushita et al [8] studied the influence of the nodularity on the thermal conductivity and corrected the traditional thermal conductivity model for ductile cast iron by changing the thickness of cuboid castings.…”

“…Ma et al [9] found that when the vermicularity (40%-90%) increased, the thermal conductivity of VGI increased, according to the numerical simulation by finite element software ANSYS. Wu et al [10] found that the thermal conductivity of VGI decreased with increasing pearlite content (10%-80%) by finite element numerical simulation. These studies provide a reference for studying the quantitative effect of microstructure on thermal conductivity of VGI cylinder blocks and heads.…”