The recrystallization process of highly oriented pyrolytic graphite (HOPG) surface bombarded by argon ions with an ion energy of 2.0-2.5 keV at doses of 2-5x10(16) ions/cm(2) was examined by scanning tunneling microscopy. The hillocks formed by the ion bombardment of HOPG coalesced to form larger grains with increasing annealing temperature. Three types of ringlike superstructures of (root 3 x root 3)R30 degrees of graphite were found on the curved surface of the grains after annealing in the temperature range of 1823-2673 K. The specimen surface became flat above 2773 K, where the ringlike superstructure disappeared and the triangular structure of graphite appeared in its place. The effect of the curved surface of the grains on the formation of the ringlike superstructure during graphitization is discussed.