Perforation patterns: Round perforations, square perforations, slotted perforations, fish scale perforations, hexagonal perforations, cross perforations as well as some other special patterns. Perforated Metal Screen Sheet can be classified into Mild steel. perforated metal screen; galvanized iron perforated metal screen; aluminum perforated metal screen; stainless steel perforated metal screen; perforated metal sheets of other materials.