Stainless steel flange is a flange that extends steel pipes, fittings, etc. into the flange and connects them to equipment or pipelines through fillet welds. The inner hole on one side of the flange is equipped with a welding protrusion, and the welding protrusion has an inner hole. The inner hole is connected to the inner hole at the center of the flange, and there is elasticity between the flange and the welding boss. The two top surfaces of the elastic ring are respectively connected to the flange and the welding boss. There are many screw holes on the flange. The screw holes are symmetrically distributed around the center of the flange. Stainless steel flanges are made of stainless steel, followed by polyethylene plastic layer, rubber layer, and PVC layer. Next, let's take a look at the precautions for using stainless steel flanges.
1. To prevent corrosion between the eyes of stainless steel flanges caused by heating, the welding current should not be too high, about 20% less than that of carbon steel welding rods, the arc should not be too long, the cooling rate should be between fast layers, and the narrow weld effect is better.
2. The electrode should be kept dry during use. Perovskite type requires drying at 150 ℃ for 1 hour, while low hydrogen type requires drying at 200-250 ℃ for 1 hour (do not repeat drying multiple times, otherwise the coating is prone to cracking and peeling) to prevent contamination such as oil stains on the electrode coating, which may increase the carbon content of the weld and affect the quality of the weld.
3. When welding stainless steel flange fittings, repeated heating will precipitate carbides, reducing their corrosion resistance and mechanical properties.
4. Chromium stainless steel flange fittings with high hardenability after welding are prone to cracking in American standard flanges. If the same chromium stainless steel welding rod is used for welding, it is necessary to preheat at least 300 ℃ after welding and cool slowly at around 700 ℃. If the welded parts cannot undergo post weld heat treatment, stainless steel flange pipe welding rods should be used.
5. For stainless steel flanges, add appropriate stabilizing elements such as Ti, Nb, Mo, etc. to improve corrosion resistance and weldability. Weldability is superior to chromium stainless steel flanges. When using the same type of chromium stainless steel flange welding rod, it should be preheated to over 200 ℃ and tempered at around 800 ℃ after welding. If the welded parts cannot undergo heat treatment, stainless steel flange pipe welding rods should be used.
6. Stainless steel flange fittings and butt welded flange electrodes have good corrosion resistance and oxidation resistance, and are widely used in chemical, fertilizer, petroleum, and medical machinery manufacturing.
