... steel and bars with certain distances, the high pressure resistance welding machine welding of the original plates, by cutting, incision, opening, ... trestle bridge, ditch cover, covers, ladders, fences and railings. Series 1 (pitch 30mm) steel grating is the most common type ... panels, trestle, protective fencing, sun screens and so on. Series 3 (pitch 60mm) grating is a special application for the ...