Restore treatment of steel cast surface: cold-rolling mill is the main part of cold rolling strip steel machine. Its frame is made of cast steel. It needs unique technology to restore the connatural flaw of cast steel.

First, adopting welding to restore. It includes manual arc welding, gas shielded welding or argon arc welding. Then, it needs expert method to restore inside flaw and outside flaw. To inside flaw, it adopts milling machine processing. To outside flaw, the point dispersion flaw it adopts manual drilling tool or milling machine; sand hole it adopts knocking sand hole to make it loose, then using alloy grinding head to grind, to bulk flaw it adopts boring mill processing.

Cleaning and welding. To small flaw on the surface it adopts argon arc welding and polishing. Adopting above methods, it can restore the flaw.