Stainless steel flanges are flanges that insert steel pipes, pipe fittings, etc., into the flange and connect them to equipment or pipelines through fillet welds. The inner hole on one side of the flange is provided with a welding protrusion, and the welding protrusion is provided with an inner hole. The inner hole communicates with the inner hole in the center of the flange, and there is elasticity between the flange and the welding protrusion. The two top surfaces of the elastic ring are respectively combined with the flange and the welding protrusion. 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. Let's take a look at the precautions for the use of stainless steel flanges below.

1. To prevent intergranular corrosion caused by heating of stainless steel flanges, the welding current should not be too large, about 20% less than that of carbon steel welding rods, the arc should not be too long, and the cooling speed should be fast between layers, and the narrow weld bead effect is better.

2. The electrodes should be kept dry during use. Perovskite type needs to be dried at 150℃ for 1 hour, and low hydrogen type needs to be dried at 200-250℃ for 1 hour (do not repeat drying many times, otherwise the coating is easy to crack and peel off) to prevent the welding rod coating from sticking to oil stains and other pollutants, so as to avoid increasing the carbon content of the weld and affecting the quality of the weldment.

3. Repeated heating during welding of stainless steel flange pipe fittings will precipitate carbides, reducing corrosion resistance and mechanical properties.

4. After welding, chromium stainless steel flange pipe fittings with high hardenability are prone to cracking. If the same type of chromium stainless steel welding rod is used for welding, the weld should be preheated above 300℃ and slowly cooled at about 700℃. If the weldment cannot be post-weld heat treated, stainless steel flange pipe welding rods should be used.

5. For stainless steel flanges, an appropriate amount of stabilizing elements such as Ti, Nb, and Mo are added 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, the weld should be preheated above 200℃ and tempered at about 800℃. If the weldment cannot be heat treated, stainless steel flange pipe welding rods should be used.

6. Stainless steel flange pipe fittings and butt welding flange electrodes have good corrosion resistance and oxidation resistance, and are widely used in chemical industry, chemical fertilizer, petroleum, and medical machinery manufacturing.