METHOD OF TESTING FOR AND PREVENTING THE POSSIBILITY OF CRACKING, SPALLING OR LIKE DEFECTS IN A BODY SURFACE SUBJECTED TO MECHANICAL FORCES

摘要

In a method of testing for and preventing the possibility of cracking, spalling or like defects in a rolling mill roll surface the surface is scanned to provide a representation of the hardness and/or the magnetic conductivity. The presence at a location of a rate of change of this characteristic of greater than a predetermined amount foreshadows the possibility of the occurrence of such a defect at this location. The roll is then subjected to an operation consisting of removal of the surface portion or heat treatment until the rate of change is below another predetermined amount. Preferably the method used to measure magnetic conductivity is eddy current testing. The removal operation may take place in steps until the rate of charge is below the another rate of charge.