Precautions for use of stainless steel flange

　　1. In order to prevent the corrosion between the eyes caused by the heating of the flange cover, the welding current should not be too large, about 20% less than the carbon steel electrode, the arc should not be too long, the interlayer should be cooled quickly, and the narrow weld bead is suitable.

　　2. The welding rod should be kept dry when it is used. The titanium calcium type should be dried at 150 ℃ for 1 hour, and the low-a hydrogen type should be dried at 200-250 ℃ for 1 hour (it cannot be repeatedly dried, otherwise it is easy to crack and peel off), so as to prevent the coating from sticking oil and other dirt, so as not to increase the carbon content of the weld and affect the quality of the weldment.

　　3. When welding stainless steel flange pipe, carbide precipitates under repeated heating, which reduces the corrosion resistance and mechanical properties.

　　4. After welding, chromium stainless steel flange pipe fittings have large hardenability, American standard flange is easy to crack. If the same type of chromium stainless steel electrode is used for welding, preheating above 300 ℃ and slow cooling treatment about 700 ℃ after welding must be carried out. If the post weld heat treatment can not be carried out on the weldment, stainless steel flange pipe electrode shall be selected.

　　5. In order to improve the corrosion resistance and weldability of stainless steel flange, adding appropriate amount of stable elements such as Ti, Nb and Mo, the weldability is better than that of chromium stainless steel flange. When using the same type of chromium stainless steel flange electrode, it should be preheated above 200 ℃ and tempered about 800 ℃ after welding. If the weldment can not be heat treated, stainless steel flange welding rod should be used.

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