Nondestructive assessment of carbide content, hardness and case depth at the surface of cast iron parts

A common problem in surface machining of gray cast iron parts is due to formation of carbide at the surface, which results in decreasing cutting tool life and increasing production cost. Therefore, detection of hardened layer and its hardness are key factors in quality control and inspection processes. In the present paper, nondestructive evaluation of metallurgical parameters (surface carbide, surface hardness and hardened depth) has been investigated using eddy current technique. The results show the high potential of the proposed method as a fast an accurate nondestructive technique in determination of metallurgical parameters affecting hardness of the surface and consequently separation of undesirable parts.