This article introduces the usual flaw of carbon cold rolling steel strip surface that is pressing and oxidizing black spot defects characteristic and cause of its formation.

The results indicated that the dark features were such a kind of defects that embody pores and poor quality diamond phase located at grain boundaries of diamond films.

On the basis of the observation of practical defects in ceramic tiles and the limitations of the conventional model of rough sets, this paper proposed a new method of defect analysis for ceramic tiles by introducing a variable precision rough set model which uses approximation dependency of variable rough sets to realize attribute reduction and to establish decision making rules.

It's systemic studied the effect of casting speed and water consumption rate on central defects of high quality and high carbon grade billet which belong to the No.