Magnetic inspection of the hardness of cast-iron milling rolls

The effects of the chemical composition and parameters of the cast-iron smelting and teeming process on the coercive force have been studied. It is shown that only chromium and carbon appreciably affect the coercive force. For rolls with cylindrical surfaces cast from ТПХН-60 iron, a reliable correlation has been established between the hardness and readings of a coercimeter with an attachable electromagnet. For flanges and blooming passes of sizing rolls made from ТШХН-50 cast iron, equations for the relation between the hardness and readings of a coercimeter have been obtained and analyzed. These equations can be used in nondestructive testing of hardness.