Although stainless steel flanges have unique advantages in terms of materials, no matter how good they are, they need to be used with caution so that they can be used for a longer time.

So what precautions should be taken when using stainless steel flanges?

1. To prevent inter-eye corrosion caused by heating of the flange cover, the welding current should not be too large, about 20% less than that of carbon steel electrodes, the arc should not be too long, and the interlayer should be quickly cooled, and narrow welds are preferred.

2. The welding rod should be kept dry when used. The titanium calcium type should be dried at 150℃ for 1 hour, and the low hydrogen type should be dried at 200-250℃ for 1 hour (it cannot be dried repeatedly, otherwise the coating will easily crack and peel off). Prevent the coating of the welding rod 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 fittings, carbides are precipitated by repeated heating, which reduces corrosion resistance and mechanical properties.

4. The hardening American standard flange of chromium stainless steel flange pipe fittings after welding is larger and prone to cracks. If the same type of chromium stainless steel welding rod (G202, G207) is used for welding, it is necessary to preheat at more than 300℃ and slow cooling at about 700℃ after welding. If the weldment cannot be heat treated after welding, a stainless steel flange pipe fitting welding rod (A107, A207) should be used.

5. Stainless steel flanges, to improve corrosion resistance and weldability, appropriate amounts of stable elements Ti, Nb, Mo, etc. are appropriately added, and the weldability is better than that of chromium stainless steel flanges. When the same type of chromium stainless steel flange welding rod (G302, G307) is used, preheating at more than 200℃ and tempering at about 800℃ after welding should be performed. If the weldment cannot be heat treated, a stainless steel flange pipe fitting welding rod (A107, A207) should be used.

The above is a brief introduction to the use of stainless steel flanges, but the specific use process may be more complicated, depending on the specific situation.