Microscopic examination of the 2,300‐year‐old excavated steel plowshare from northern India.

In the present investigation, X‐ray diffractometer, optical microscope, and scanning electron microscope were used to analyze the plowshare excavated from Ganwaria, UP, India. The main objective of the investigation was to determine the type of alloy, analysis of slag inclusion, and corrosion behavior. X‐ray diffraction analysis showed the presence of α‐iron. Microstructure consists of ferrite and pearlite grains; ferrite phase was soft in comparison to the pearlite. Optical micrograph at lower magnification revealed slag inclusions aligned in a specific direction, which indicates that the forge welding technique was used in the manufacturing of the object. The microstructural examination revealed that the object was manufactured from carbon steel. Entrapped slag inclusions were observed by scanning electron microscope and X‐ray mapping, and slags were identified as SiO2 and MgO. Goethite and lepidocrocite corrosion compound were found on the surface of the object. [ABSTRACT FROM AUTHOR]