1. Causes of Corrosion and Damage of Coloured Steel Plates
1. The serious decay of roof color steel plate is the result of the combined action of high temperature air flow and oxygen and sulfur decay. The main reason for the increase of corrosion rate is the super high concentration of CO2 in the local environment of workshop roof. It is suggested to spray rust-proof paint or vein-gathering material on the surface of color steel plate, improve the production process and process, and do regular inspection and online inspection.
2. The stainless steel roof of the production workshop is severely corroded in many places. Local corrosion has been perforated and cracked, and the corroded area of the roof above is larger. There are many pits and large areas of uniform corrosion on the outer surface of the stainless steel roof, and the corrosion in the bend is the most serious. Some of the bends penetrate and form cracks, as shown in Figure 2, especially near the exhaust smoke. On the roof edge above the road and gate, the stainless steel plate is corroded and peeled off in many places, as shown in the figure. The blue coatings of color steel sheets without obvious corrosion were observed at close range. It was found that the ageing, cracking, foaming and shedding of the coatings had also occurred. The more close to the corrosion area, the more obvious the ageing cracking degree was.
3. The high temperature air generated by the open coal-fired heating process in the production workshop is discharged through the rusted cracks in the roof, the simple exhaust pipe and the nearby windows. Several stainless steel sheets with serious corrosion were observed by field emission scanning electron microscopy. From Figure 3, it can be seen that the inner surface is more seriously corroded than the outer surface, but the inner surface is mainly uniformly corroded, with fewer pitting pits, more average corrosion depth and slightly lighter overall corrosion on the outer surface, but with more pitting pits and local corrosion characteristics, and the local pitting depth or cracking depth is larger. The sulphur content of the rust layer on the outer surface is very high at individual locations. The sulphur content on the outer surface should be the result of the concentration of sulphur dioxide aqueous solution on the outer surface. The value of the concentrated sulphur dioxide aqueous solution decreases and the corrosiveness is stronger.
Second, how to judge the quality of color steel plate
Colored steel plate is more and more widely used in society. It occupies an important position in new buildings which are concerned and accepted by people, such as movable panel houses. So the following result is how to find an excellent colored steel plate in many colored steel plates. Next, let's look at some techniques of distinguishing colored steel plate summarized by Xiaobian.
1. First of all, we should reflect on the quality certification of color steel plate, and whether there are relevant inspection standards. Investigate the company's reputation and reputation in the market before it is purchased. It's better to stop on-the-spot investigation to the consumer factory of color steel plate to see how the environmental equipment of the company is and whether it is on track.
2. We can know the quality and quality of coloured steel plate only through price. Everything is a penny for a penny. When comparing the quality of coloured steel plate, price is only one of them, and it is not necessary to pay too much attention to price. But when the price of one kind of coloured steel plate is much lower than that of the others, the enemy who wants to buy it must be considered.
3. Observe whether the exposed steel, such as cross-section, can crystallize fine, gray, dark and impurities. Assuming that the section is fine crystalline, the quality is excellent. The thickness of basal plate and peritoneum were observed.
4. If the color steel plate is struck with finger or hard object, the metal sound of the color steel plate with better material is louder and louder. If the material of the color steel plate is assumed to be worse, the sound will be dull and the metal sound is not clear.