METALLOGRAPHIC STUDY OF IRON ARTEFACTS FROM THE EASTERN TRANSVAAL,SOUTH AFRICA

The microstructures of two adzes, two hoes and a spear point from Iron Age settlement sites in the Kruger National Park have been examined. Electron microprobe analyses of the slag inclusions were also made. Some of the objects are made of high carbon steel while others have a highly variable carbon content. All appear to have been forged at relatively low temperature and then annealed at a low temperature near 700°C. None have been hardened by quenching and tempering. Some of the objects contain only traces of included slag while others have large slag inclusions. The slag compositions are quite different from those of medieval bloomery slags and are representative of African iron smelting practice in their high content of CaO, K₂ O and Na₂O. On the basis of the titanium content of the included slag, two of the objects are identified as made of the ore from Rooiwater and one from Phalaborwa ore.