Inspection of mill rollers

The metal’s state inspection using the MMM method on working and backup rolls before and after carrying out of reconditioning repair technologies on them allows assessing the quality of these technologies, the structural changes, as well as the level and the distribution of residual stresses. Inspection of new rolls at the manufacturing plants using the MMM method provides the possibility to carry out the quality assessment of the production technology itself.

Fig.1 shows the scheme of the inspection by the MMM method on the working surface of the rolls.

Fig.1. The scheme of the inspection by the MMM method on the working surface of the rolls: — the zone of the roll’s working surface inspection; 1, 2, 3, 4, 5, 6 – numbers of sections; -> – the direction of movement of the recording device of the TSC-type instrument.

Fig.2 shows the inspection results, obtained using the MMM method, of the ?350 (section 6 according to the scheme of fig.1) backup shaft of the strip-feeding plant before the heat treatment “by extraction” (fig.2, a) and after the heat treatment (fig.2, b).

Fig.2a. Results of the inspection by the MMM method before the heat treatment.	Fig.2b. Results of the inspection by the MMM method after the heat treatment.