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Rasouli A, Hejebri Nobari A, Khamseh H. The Technology of Metal Objects in the North and Northwest of Iran during the Iron Age based on Metallographic Experiments. JRA 2019; 5 (2) :105-115
URL: http://jra-tabriziau.ir/article-1-145-en.html

In archaeological survey of Iron Age of North and Northwest of Iran, the study of metal objects is of great importance because of their technical values. Based on archaeological findings of the first millennium BC, the use of metals in the plateau of Iran and other neighboring areas was spread dramatically. As in the Iron Age, a new phase in manufacturing of metal objects was emerged, recognizing the production methods are the important issues in the archaeology of this period. In fact, this Age is associated with the advancement of metal melting furnaces and the manufacturing of metal objects with fairly sophisticated methods. In the sites of Iron Age of Northwest of Iran, the metallurgy was carried out at an advanced level; while the development of the metallurgy tradition Age can be seen in different part of Iran. This diversity is based on metal objects and metal melting molds from the Iron Age sites of Northwest of Iran, especially from Hasanlu and Ziwiyeh, where most of them have high motifs and manufacturing technology, and also based on the metal objects in the Iron Age sites of Mazandaran region, where most of them have a simple shape and no decoration. It can be said that there is more complexity and diversity in the methods of making metal objects in the Iron Age sites of Northwest of Iran compared to that of the North regions of Iran. This research was done based on the analytical methods as well as the field and laboratory studies. The metal objects used in this research were collected from the archaeological excavation, kept in the store of national museum of Iran. After sampling for metallurgical testing, the samples were sent to the metallurgy and materials laboratory of Sharif University of Technology, where they have been studied by Scanning Electron Microscopy (SEM) In this study, seven samples of metal objects were selected for metallography testing, which five of them were related to the Northwest of Iran and two others were related to the North region of Iran. The criterion that has been considered for the selection of the samples was that the discovered samples from the Northwest of Iran as well as metal mine and fuel recourses have been geographically close to each other. Based on the results obtained by metallographic testing and images taken by SEM, it was found that they have been manufactured mainly with two methods. Warm hammering and casting were the main methods of production of metal objects in the Iron Age sites in North and Northwest of Iran. On the hammered production method, a mechanical work such as forging has been done after casting. Therefore, their microstructure was different under the microscope. The metal objects discovered from the Iron Age of Mazandaran region compared to that of the Northwest of Iran sites, have a simple shape and manufacturing technology. This could be probably due to the existence of the most powerful empires such as Urartu and Manna in the vicinity of the Northwest region, and therefore more skilled metallurgist, artists and technologists in this region of Iran. All in all, the metal objects discovered from Iron Age sites of Northwest, especially Hasanlu, regarding the techniques and style of production, are more complex than that of the Iron Age sites of Mazandaran in the North of Iran, which have indigenous and local governance.