Below is a list of Metal Grates manufacturers from. Metal grates are constructed from bars, plates or grids and used in floors, stairs, filter systems and enclosures to provides structural support, a semi-permeable surface or a protective grid or filter. Typically constructed from aluminum, steel or stainless steel, metal grates are popular for outdoor ramps and stairs, can be used to cover storm drains and sewers and in factory floors where it is necessary to keep the floor free of debris and liquids, or where a non-slip surface is required.