ʻO ka hao hao ka mea nui o ke ala kaʻaahi.ʻO ka ʻāpana o ke kaʻaahi ma ke ʻano he I-like, i haku ʻia me ʻelua mau kaʻaahi like, a ʻoi aku ma mua o 35 mau ʻāpana kaʻa.ʻO nā mea nui ka carbon C, manganese Mn, silicon Si, sulfur S, phosphorus P. ʻO ka lōʻihi maʻamau o ke kila kila o Kina he 12.5m a me 25m, aʻo nā kiko'ī o ke kila kila he 75kg / m, 90kg / m, 120kg / m. .