The as cast microstructure and properties of lzqt600-3 ductile iron profile were studied. Firstly, according to GB / T 9441-2009 metallographic examination of nodular cast iron, the size and spheroidization grade of graphite ball were evaluated qualitatively. Then, the number of graphite balls, average shape factor of graphite balls, pearlite content in matrix and pearlite lamellar spacing in ductile iron profiles were calculated quantitatively by Image J software. Finally, the wear resistance and corrosion resistance of the samples in different parts were tested based on the change law of the microstructure in different parts. The main conclusions are as follows

(1) The results show that the average diameter of graphite balls increases from the edge, 1 / 2R to the center of lzqt600-3 ductile iron profile, and the spheroidization level decreases in turn: the number of graphite balls decreases from 318 / mm2 to 312 / mm2 and 303 / mm2; the average shape factor of graphite balls decreases from 0.724 to 0.672 and 0.660; the average straight diameter of graphite balls increases from 29.86 μ m to 26.78 μ m and 31.03 μ M.

(2) The amount of pearlite in lzqt600-3 ductile iron profile increases from 64.36% to 65.90% and 70.84% from 1 / 2R to the core, and the pearlite lamellar spacing increases from 274 nm to 286 nm and 316 nm.

(3) The friction coefficients of lzqt600-3 ductile iron profile from the edge, 1 / 2R to the center are 0.565, 0.612 and 0.611 respectively, and the wear rates are 3.373, 1.337 and 1.679, respectively. The wear degree of 1 / 2R is close to that of the center, which is better than that of the edge.

(4) Lzqt600-3 ductile iron profile has the best corrosion resistance at the edge, 1 / 2R is slightly lower than the edge, and the core is the worst.