RESEARCH AND DEVELOPMENT OF HEAT AND WEAR RESISTANT MATERIALS

The purpose of this research project is to research and develop the new cast alloys combining heat resistance with abrasion wear resistance on the basis of richness in studies and experience for abrasion wear resistant high Cr cast irons(Fe-Cr-C alloy)and that of knowledge for super alloys.In order to improve the heat resistance of Fe-Cr-C alloy，Fe in the alloy was displaced by Ni in 25%，50%，70%of the total mass percent and in100%of Fe。Then，solidification structure，solidification process and high temperature characteristics were investigated on both the respective alloys of Fe-Ni-Cr-C systems.According to X-ray diffraction and EDS analysis，the precipitated phases that supported the wear resistance were found to be M I D27 I D 2 C I D 23 D 2 or Cr I D 27 D 2 C D 23 D 2 carbides.In the matrix，austenite(γ)was stabilized with an increase in Ni content。As Ni content increased up to 50%at any Cr levels，the eutectic C content was moved to a low C side and，in more Ni co…More ntent than 50%，it was shifted conversely to a high C side。Precipitation of graphite due to Ni addition was suppressed by designing the alloy combination of Cr and C.The softening of matrix due to the increase ofγwas compensated by addition of Al that formed a Ni Ii D23 I D 2 Al intermetallic compound and mostly dissolved into matrix.It is expected that these results can lead the improvement of strength and wear resistance of the alloys.The solidification of the Fe-Ni-Cr-C alloy was follows，L→primaryγ→(γ+M I D27I D2)eutectic in the hypo-eutectic composition and L→primary M I D27E D2→(γ+M I D27E D2)eutectic in the hyper-eutectic composition and L→primary M I D27E D2→(γ+M I D27E D2C)eutic in the hyper-eutic composic in the hyper-eutic the hyper-eutic composition and the hyper-in the hyper-eutic compositic the hyper-eutic composition and the hyper-eutic composition of the hyper-eutic composectic the hyper-eutic d2.Was largest in a eutectic alloy，followed by hyper-eutectic alloy，and smallest in a hypo-eutectic alloy。Under the same Ni content，the oxidation resistance was greatly improved as Cr content increase up to 30%.From above research results，the practical application of this alloy at elevated temperatures is considered to be possible under the adequate circumstances.Less：Less

The purpose of this research project is to research and develop the new cast alloys combining heat resistance with abrasion wear resistance on the basis of richness in studies and experience for abrasion wear resistant high Cr cast irons (Fe-Cr-C alloy) and that of knowledge for super alloys. In order to improve the heat resistance of Fe-Cr-C alloy, Fe in the alloy was displaced by Ni in 25%, 50%, 70% of the total mass percent and in 100% of Fe. Then, solidification structure, solidification process and high temperature characteristics were investigated on both the respective alloys of Fe-Ni-Cr-C and Ni-Cr-C systems.According to X-ray diffraction and EDS analysis, the precipitated phases that supported the wear resistance were found to be MィイD27ィエD2CィイD23ィエD2 or CrィイD27ィエD2CィイD23ィエD2 carbides. In the matrix, austenite (γ) was stabilized with an increase in Ni content. As Ni content increased up to 50% at any Cr levels, the eutectic C content was moved to a low C side and, in more Ni co … More ntent than 50%, it was shifted conversely to a high C side. Precipitation of graphite due to Ni addition was suppressed by designing the alloy combination of Cr and C. The softening of matrix due to the increase of γwas compensated by addition of Al that formed a NiィイD23ィエD2Al intermetallic compound and mostly dissolved into matrix. It is expected that these results can lead the improvement of strength and wear resistance of the alloys.The solidification of the Fe-Ni-Cr-C alloy was as follows, L→ primary γ→ (γ+MィイD27ィエD2CィイD23ィエD2) eutectic in the hypo-eutectic composition and L → primary MィイD27ィエD2CィイD23ィエD2 → (γ+ MィイD27ィエD2CィイD23ィエD2) eutectic in the hyper-eutectic composition.The oxidation resistance of the Fe-Ni-Cr-C alloy, as a high temperature or a heat resistant characteristics, was largest in a eutectic alloy, followed by hyper-eutectic alloy, and smallest in a hypo-eutectic alloy. Under the same Ni content, the oxidation resistance was greatly improved as Cr content increase up to 30%.From above research results, the practical application of this alloy at elevated temperatures is considered to be possible under the adequate circumstances. Less