Eddy current testing technology of forged steel cold roll

When the eddy current flaw detector was used to test the roll, it was found that there were eddy current soft spot signals in some roll products after normal heat treatment and before it was put into rolling use. Hardness test, chemical composition analysis, metallographic examination and residual stress test were used to accurately locate the eddy current soft spot signal, and the effect of the sample was tracked. The results show that the generation of eddy current soft spot signal was related to the uneven distribution of residual stress on the surface of the workpiece during quenching. This kind of signal would be rapidly reduced in the first few cycles of roll use, and would not adversely affect the use of the roll.