The Establishment of Casting Technologies for Heavy Section Ductile Irons Castings with Specified Low Temperature Impact Property

The primary purpose of this research is aimed at 2MW hub to establish the design of the hub mold and manufacturing, the design of gating system and filling and solidification simulation, furan molding, the optimal alloy design and casting condition for achieving the desired mechanical properties (tensile strength, yield strength, elongation and impact value under -20oC) of 2MW hub used in large-scale windmills. Establish the practical casting expertise of 2MW large-scale windmill hub and use the derived regression equations to inspect and verify the results of chemical compositions, microstructures and mechanical properties. On the other hand, the effect of resistance to corrosion (NSS and CASS salt spray test) of Zn-Al arc spraying coating on the specimens was also investigated in this study. The experimental results show that the cast-on specimens of 2MW hub can meet the specification of EN-GJS-400-18U-LT including microstructure (nodularity, nodule count and pearlite percentage) and mechanical properties. Also, the thickness of Zn-Al arc spraying over 200µm can pass the 120hr salt spray test.