In an aim to create a material with better characteristics than cast iron, hybridization of cast iron and ceramics was experimented. This process was carried out using ‘cast-in inserts’ of melted cast iron in an ceramic column. The temperature of the molten metal, pouring weight and pre-heating temperature of the ceramic etc. were varied, and the condition and outcome of the cast in insert were evaluated. The generation of cracks in the ceramic was also investigated.
  The generation of cracks in the ceramic was found to be preventable by pre heating the ceramic to a temperature of 1273 K or higher. In doing so, the ceramic still clung well to the cast-in inserts. Cracks in the alumina ceramics occur when the temperature inside the ceramics fluctuates as the cast iron ‘cast -in inserts’ are inserted. However, the ceramics will not crack if the temperature difference is less than 225 K. This can be achieved by pre-heating the ceramics to 1273 K or more.
  This was confirmed through calculation of non-steady state heat conduction and heat stress numerical analysis.

抄録全体を表示

  Spheroidal graphite cast iron welded joints were made by TIG using 5 Fe-Ni welding rods ; 83 Fe-10 Ni, 73 Fe-20 Ni, 63 Fe-30 Ni, 53 Fe-40 Ni and 43 Fe-50 Ni. By investigating the Vickers hardness and microstructure of the welded joints in the welded boundary layer, weldability is estimated. Then, to clarify the reliability of the welded joints, tensile and fatigue tests using the welded joints and base metal were also carried out, and the tensile strength and S-N curve obtained from these tests were compared. The results showed that the 5 Fe-Ni welding rods used are effective in preventing the formation of white cast iron during welding, and that the fatigue limit of the welded joint using the 73 Fe-20 Ni welding rod is equal to that of the base metal.

抄録全体を表示

  To improve the brake performance of cast iron shoes, presently steadite is precipitated as a hard phase in alloyed cast iron, shoes used for rolling stock. To generate other hard phases in cast iron, we designed and manufactured cast iron composites, including Silicon Carbide (SiC) and Partially Stabilized Zirconia (PSZ) ceramic filters, and examined how these hard phases and their compositions in cast iron affect frictional and wear performance.
  The hard phases in cast iron increase the frictional coefficient, decrease the wear of block and increase the wear of disc. Steadite and SiC have the same effect as hard phases. These effects increase when the two are used in combination. On the other hand, PSZ is less effective as hard phases, even when added to steadite.

抄録全体を表示

  This paper describes the advanced control of automatic pouring process, with focus on the liquid level control in a sprue cup. In order to realize the objective, the model of the liquid level process was analyzed, and the feedforward input was computed by control simulation. Furthermore, the control system was developed by two-degree-of-freedom control that combined the feedforward control with feedback control, in order to guarantee robustness for changes in the pouring situation. The effectiveness of the proposed system is shown through simulations and experiments.

抄録全体を表示

  Selective incorporation of reinforcing particles in a specific portion of composite components is strongly desired for the machining and recycling of these components, as well as for reducing reinforcement and processing costs, This paper presents a selective incorporation method of composite slurry through an electromagnetic process, especially effects of the slurry diameter, solidification rate and particle size on the particle segregation are discussed, The non-conductive oxide particles of MgAl₂O₁ are forced to segregate to the outer periphery by the application of electromagnetic buoyancy during solidification of the in situ composite slurry prepared from a SiO₂, Al-Mg system. The particle segregation is mainly governed by two factors : (a) the solidifying period of the slurry must be longer than the electromagnetic migration time of particles, (b) the ratio of composite slurry diameter (2γ₀) to the electromagnetic skin depth (δ), that is, 2γ₀/δ must be around 3, because the optimum upward recirculating flow is necessary for preventing the particles from sedimentation. Furthermore, the volume fraction in segregated zones becomes larger towards the outer periphery, and larger with composite slurry containing large particles.

抄録全体を表示

  Numerical simulation of the solidification of T-junctions of an aluminum alloy revealed that the locality in solidification is less apparent than in cast iron; e.g. , the cooling effect of a thin fin attached to a plate is more apparent and heating effect at a thick junction is less apparent. One typical result is that hot spots formed at a thick junction of the aluminum alloy can be eliminated by adding a thin fin, whereas they cannot be eliminated in cast iron by the same method. The increase in solidification time at a junction with the increase in the fillet radius is only half of that of cast iron. The range of cooling effects at the end of the plate is two times longer in the aluminum alloy than in cast iron.

抄録全体を表示

  Residual stress on the fire surface of gray cast iron cylinder heads was examined. The measurements were carried out on two types of cylinder head using the cutting methodology. One was the non-operated head and the other was the 500hr operated head.
  The residual stress on the surface of the non-operated head was found to be compression stress in the principal stress analysis. On the contrary, tensile residual stress occurred in the operated head. This was considered to be the effect of compression plastic deformation due to the high compression thermal stress resulting from repeated thermal load during engine operation. The residual stress distributions in the thickness direction of the fire surface were also investigated. The residual stress distribution in the operated head was relaxed as compared with non-operated head. Inserting the valve seat generated static tensile stress on the fire surface. This stress was a considerably large value.

抄録全体を表示

  As cast iron is opaque, it is difficult to grasp three-dimensional images of spheroidal graphite.
  In this study, a three-dimensional image of spheroidal graphite was constructed from cross-sectional images of spheroidal graphite. The cross sections of spheroidal graphite were photographed using a digital camera, and their images were processed using a personal computer. A new computer program for constructing the three dimensional images of spheroidal graphite was developed.
  Constructed spheroidal graphite images can be displayed by rotating around three axes.

抄録全体を表示