Steel grating is twisted 5mm × 5mm, 6mm × 6mm or 8mm × 8mm cross-section of the square steel and a number of loaded flat steel into a straight intersection welded into a whole, constituting a good load-bearing capacity of the open grating-type structural panels. Loaded flat steel is usually 3mm, 5mm thick flat steel, can also be used "I" section of flat steel and flat steel with teeth. The width of the loaded flat steel (i.e. the thickness of the grating) is from 20mm to 75mm. the spacing of the flat steel is usually 30mm or 40mm, or 15mm, 25mm, 35.3mm, 60mm, etc. The spacing of the crossbar is usually 100mm. The spacing of the crossbar is usually 100mm or 50mm, or 30mm, 33mm, 150mm, etc., thus constituting a different series of steel grating with various specifications.