한국주조공학회

The purpose o f this study was to investigate the effects o f silicon and nickel additions that influenced the impact and tensile properties o f heavy section as-cast ductile irons for wind mill. Based on the results o f the metallographic analysis and the mechanical testing on the 2.0 wt.%Si (LS group) and 2.4 wt.%Si (HS group) ductile irons，which contains 0.0, 0.3，0.6 and 0.9 wt.%Ni, respectively, the following conclusions could be obtained. The nickel additions increased the tensile properties, the microhardness o f pearlite, and the pearlite fraction o f matrix for the specimen with the same silicon content. The mechanical properties o f LS group specimen were in the range o f the specification for the ductile iron wind m ill castings. The LS group specimens showed higher absorbed impact energy at room temperature and -20°C than that o f the HS group specimens. However, the absorbed impact energy at -20°C for the HS group specimens was observed to be sharply decreased under 10 J by addition o f the nickel.

Ductile Iron, Wind miU, Silicon and nickel additions, Impact energy.