Most of the long-term requirements of maintaining the original appearance of the building. To determine the choice of stainless steel products in stainless steel type, the main consideration is the aesthetic standards required by the system to be used to clean the corrosion and the location of the atmosphere. However, a growing number of other applications, or just looking for the integrity of the structure is not permeable. For example, industrial building roof and side walls. In these applications, the construction cost of ownership may be more important than the aesthetic, the surface is not very clean and can be. Effect of using 304 stainless steel in dry indoor environment is quite good. However, in rural and urban outdoors in order to maintain their appearance, they need regular cleaning. In heavily polluted industrial areas and coastal areas, the surface will be very dirty, and even rust. But to get the aesthetic effect of the outdoor environment, it requires the use of nickel-containing stainless steel. So, 304 stainless steel is widely used in curtain wall, side walls, roofs and other construction purposes, but in severe erosion of industrial or marine atmosphere, the best use of 316 stainless steel. There are several design criteria are included in the 304 and 316 stainless steel. Because "duplex" 2205 has already good resistance to atmospheric corrosion and high tensile strength and elastic limit of integration, so that the European criteria also included the steel. Product shape, in fact, stainless steel is the whole shape and size of the standard metal manufacturing, and there are many special shapes. The most commonly used products are made with sheet and strip, and plate production with special products, for example, the production of hot-rolled structural steel and structural steel extrusion. And there are round, oval, square, rectangular and hexagonal welded or seamless steel tubes and other forms of products, including profiles, rods, wire and castings. In order to meet the aesthetic requirements of architects, has developed a wide variety of commercial surface processing. In building applications, stainless steel surface processing is important for a number of reasons. Corrosive environments require a smooth surface is not easy because the smooth surface fouling. Deposition of dirt will cause corrosion of stainless steel to rust even.