Weathering steel possesses workability similar to ordinary steels. Cor-Ten sheets or coils can be cut thermally or mechanically using similar procedures to those used on structural steels of the same thickness. It also can be welded, both manually and mechanically. More specifically, and related to IMAR´s façade solutions, the panels can be perforated, expanded or embossed. The plates can be shaped into a wide range of geometries to achieve the required functional and aesthetic requirements, including curved shapes if required. We can manufacture and supply façade panels of different thickness and sizes, only limited by the size of coils.
Nonetheless, it is difficult to predict the final colour of weathering steel due to its extremely reactive surface. The coloration is hardly guaranteed to be consistent. The evolution (characteristics and speed) of the patina, therefore the colour, varies and depends mainly on: • Local weather conditions (i.e. exposure to sun, average temperature, orientation to prevailing winds, humidity, etc.) • Location: industrial, urban, maritime or country-side climate. • Orientation of façade (i.e. exposed to or shaded from the weather, vertical or horizontal position, etc.) • Corrosive character of the atmosphere (i.e. concentration of sulphur dioxide, SO2, and chlorides). In industrial settings the patina forms more quickly and is darker in colour than in rural areas. In marine locations, the formation of the protective patina may be slower due to chloride exposure. However, in both cases, the patina does not adhere as well to the steel substrate and may not protect the steel from corrosion. In the other hand, surfaces directly exposed to the weather will have a finer grain than sheltered facades. The patina formed on surfaces which are not directly exposed to weather are generally not as uniform as that on parts which are alternately made wet and dried. Small variations in colour may also occur on areas which are subjected to strong local variations of temperature, wind or humidity. To get the best results and beautiful rust coating, weathering steel requires an alternating cycle of wet and dry conditions. Moisture helps to create the oxide layer. As it dries, the oxide layer starts to dehydrate, resulting in a compact adherent layer with low-permeability: the protective patina. During patina formation, some of the oxides are washed out by rain. The amount of oxide leached out by the rain diminishes over time, but never stops completely. This can stain neighbouring materials. Careful design of the facade is needed to ensure that the oxidised rainwater is collected and directed away from other materials to eliminate staining