熱応力解析による超硬合金鋳ぐるみ多合金白鋳鉄の割れおよび変形に対する予測手法の検討

抄録

  The wear loss of some steel materials is known to increase significantly under high temperatures than under room temperature. We, therefore, focus on the cast-in insertion casting method which gives materials great functionality. In previous researches, we reported that the combination of cast iron and hard carbide by this method improves heat and wear resistant characteristics. However, some of cemented carbide cast-in insertion specimens were found to crack or deform after solidification. Thus, in this study, we conducted thermal stress analysis using the finite element method, and established a prediction method for the cracks and deformations of cemented carbide cast-in insertion multi-component white cast irons after solidification. Analysis was carried out on the cooing process, from solidification temperature (1423 K) to room temperature (298 K). Multi-component white cast iron was selected for the base metal of the cast-in insertion specimens and cemented carbide (WC and TiC) for the cores. The dimensions of the analyzed model were 50 × 235 × 20 mm, and cuboidal cores (□10 × 235 mm) were placed at bottom and central position. TT

  The results of the thermal stress analysis showed that the specimens in which the WC core is placed at the base curved downward due to the difference in the base metal volume between the upper side and the lower side. This enabled reproducibility of the deformation tendency of cast-in specimens after solidification. In addition, thermal stress during cooling significantly reduced when the core was changed from WC to TiC, which is thought to reduce the damage of cast-in specimens by thermal stress. These results suggest that the TiC specimen placed at the center is suitable to reduce thermal stress and deformation.