ʻO nā paipu hao hao nodular he mau paipu hao ductile, nona ke ʻano o ka hao a me nā waiwai o ke kila, no laila ko lākou inoa. ʻO ka graphite i loko o nā paipu hao ductile aia ma ke ʻano spherical, me ka nui maʻamau o 6-7 mau māka. Ma keʻano o ka maikaʻi, pono e hoʻomaluʻia ka pae spheroidization o nā paipu hao hao ma nā pae 1-3, me ka nui o ka spheroidization o ≥ 80%. No laila, ua hoʻomaikaʻi ʻia nā ʻano mechanical o ka mea ponoʻī, nona ke ʻano o ka hao a me nā waiwai o ke kila. Ma hope o ka annealing, ʻo ka microstructure o nā paipu hao ductile he ferrite me kahi liʻiliʻi o ka pearlite, nona nā waiwai mechanical maikaʻi, no laila ua kapa ʻia ʻo ia he paipu kila hao.