What should we know about the use of stainless steel flange?
Although stainless steel flange has a unique advantage in material, but no matter how good things also need to pay attention to the use of places, so that can be used for a longer time.
There are the things we should know about the use of stainless steel flange:
1. In order to prevent eye to eye corrosion caused by flange cover heating, the welding current should not be too large, about 20% less than that of 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 shall be kept dry during use. The titanium calcium type shall be dried at 150 ℃ for 1 hour, and the low-a hydrogen type shall be dried at 200-250 ℃ for 1 hour (repeated drying is not allowed, otherwise the coating 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 stainless steel flange pipe is welded, carbide will be precipitated by repeated heating, which will reduce the corrosion resistance and mechanical properties.
4. After welding, the hardening American standard flange of chromium stainless steel flange pipe is large and easy to crack. If the same type of chromium stainless steel electrodes (g202, G207) are used for welding, preheating above 300 ℃ and slow cooling at 700 ℃ after welding must be carried out. If post weld heat treatment is not available for weldment, stainless steel flange pipe welding rod (A107, A207) shall be selected.
5. In order to improve the corrosion resistance and weldability of stainless steel flange, proper amount of stable elements Ti, Nb, Mo, etc. are added. The weldability of stainless steel flange is better than that of chromium stainless steel flange. When using the same type of chromium stainless steel flange welding rod (G302, G307), preheating above 200 ℃ and tempering at 800 ℃ after welding shall be carried out. If the weldment cannot be heat treated, stainless steel flange pipe welding rod (A107, A207) shall be selected.
The above is a brief introduction to the use of the lower stainless steel flange, but the specific use process may be more complex, depending on the situation.