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What Aspects Should Be Paid Attention To When Using Stainless Steel Flanges
Stainless steel flange is a flange that extends steel pipes, pipe fittings, etc. into the flange and connects with equipment or pipelines through fillet welds. The inner hole on one side of the flange is provided with a welding boss, and the welding boss 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 boss. The two top surfaces of the elastic ring are respectively combined with the flange and the welding boss. There are many screw holes in the flange. The screw holes are distributed symmetrically around the center of the flange. The stainless steel flange is 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.
1. In order to prevent the inter-eye corrosion of stainless steel flanges caused by heating, the welding current should not be too large, about 20% less than that of carbon steel electrodes, the arc should not be too long, the cooling speed should be between the number of layers, and the effect of narrow bead is better.
2. The electrode should be kept dry during use. The perovskite type needs to be dried at 150 °C for 1 hour, and the low hydrogen type needs to be dried at 200-250 °C for 1 hour (do not repeat the drying many times, otherwise the coating will easily crack and peel off) to prevent the electrode coating from sticking to oil and other pollution, so as not to increase the welding seam The carbon content affects the quality of the weldment.
3. When welding stainless steel flange pipe fittings, repeated heating will precipitate carbides, reducing corrosion resistance and mechanical properties.
4. American standard flanges with large hardenability after welding of chromium stainless steel flanges are prone to cracks. If the same kind of chrome stainless steel electrode is used for welding, it should be preheated above 300°C after welding and slowly cooled at about 700°C. If the weldment cannot be subjected to post-weld heat treatment, a stainless steel flanged pipe electrode should be used.
5. For stainless steel flanges, add appropriate amount of stable elements Ti, Nb, Mo, etc. to improve corrosion resistance and weldability. Weldability is better than chrome stainless flanges. When using the same type of chrome stainless steel flange electrode, it should be preheated above 200℃ and tempered at about 800℃ after welding. If the weldment cannot be heat treated, a stainless steel flanged pipe electrode should be used.
6. Stainless steel flanged pipe fittings and butt welding flange electrodes have good corrosion resistance and oxidation resistance, and are widely used in chemical, fertilizer, petroleum, and medical machinery manufacturing.
Stainless Steel Flange,flange
There are four types of polishing methods for dual-phase steel flanges: manual, mechanical, chemical and electrochemical. The corrosion resistance and decoration of the flange can be improved by polishing. The existing stainless steel electropolishing solution still uses phosphoric acid and chromic anhydride. During the polishing and cleaning process, some chromium and phosphorus will be discharged into the waste water. pollution of the environment.
The shielding gas pressure of the butt welding flange is to avoid slight leakage of the butt welding flange. The shielding gas in the furnace should be connected to a certain positive pressure. Assuming that it is hydrogen shielding gas, it is generally required to be above 20kBar.
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No.27 Gangqiang Road,Konggang Economic Zone,Yongxing Street,Longwan District,Wenzhou,China