How to clean up the defects of medium and heavy plate raw materials

Some defects may appear on the surface of flat ingots, blooming billets or continuous casting billets, which are used as raw materials for the production of medium and thick steel plates, due to the influence of casting process operation or billet opening process operation conditions. The common defects of flat steel ingots include transverse cracks, longitudinal cracks, scabs, surface pores, subcutaneous bubbles, shrinkage cavities, double skin, etc; Common defects in blooms include ears, folds, cracks, tension cracks, scarring, hairlines, bubble exposure, overburning, surface inclusions, scratches, etc; The common defects of continuous casting slabs include surface longitudinal cracks, surface transverse cracks, star cracks, subcutaneous pores and inclusions, bulges, internal cracks, central segregation and central porosity, non-metallic inclusions, vibration ripples, scratches, etc.

For the defects on the surface of raw materials, except for some minor defects, which will not affect the quality of steel plate due to oxidation and burning during heating and do not need to be cleaned, the defects whose size exceeds a certain limit need to be removed by some cleaning method, so as not to affect the surface quality of steel plate or cause waste products. Therefore, the surface cleaning of raw materials can not only improve the surface quality of the steel plate, but also reduce the scrap caused by the surface defects of the steel plate. It is of certain significance to save raw materials and reduce costs, and we should pay attention to this process. There are many methods of surface cleaning, such as flame cleaning, air shovel cleaning, grinding wheel grinding, machine tool processing, arc cleaning, etc. When selecting the cleaning method, the steel type of raw materials, the specific conditions of heating and rolling, and the requirements for the surface quality of finished steel plates should be considered.