But carbon steel had been made long before either Kelly or Bessemer. One of the oldest and most sophisticated methods was that of the Haya people. They’re an African tribe in what is Tanzania today. The Hayas produced high-grade carbon steel for about 2000 years.The Hayas made their steel in a kiln shaped like a truncated upside-down cone about five feet high. They made both the cone and the bed below it from the clay of termite mounds. Termite clay makes a fine refractory material. The Hayas filled the
Source: No. 385: African Steel Making
