Precautions for welding process of stainless steel flange pipe fittings

Release date：2022-06-10 23:00:00 

1. In order to prevent the corrosion between the eyes due to the heating of the flange cover, the welding current should not be too large, about 20% less than that of the carbon steel electrode, the arc should not be too long, and the layers are cooled quickly, and a narrow weld bead is appropriate.

2. The electrode should be kept dry when used. The titanium calcium type should be dried at 150°C for 1 hour, and the low-a hydrogen type should be dried at 200-250°C for 1 hour (do not repeat the drying many times, otherwise the coating will be easy to crack and peel off) to prevent The coating of the electrode sticks to 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 fittings are welded, carbides are precipitated by repeated heating, which reduces corrosion resistance and mechanical properties.

4. The chrome stainless steel flange pipe fittings have large hardening American standard flanges after welding, and are prone to cracks. If the same type of chrome stainless steel electrode (G202, G207) is used for welding, it must be preheated above 300 °C and slowly cooled at about 700 °C after welding. If the weldment cannot be subjected to post-weld heat treatment, the stainless steel flanged pipe fitting electrode (A107, A207) should be used.

5. Stainless steel flanges, in order to improve corrosion resistance and weldability, appropriately increase the appropriate amount of stable elements Ti, Nb, Mo, etc., and the weldability is better than that of chrome stainless steel flanges. When using the same type of chrome stainless steel flange electrode (G302, G307), it should be preheated above 200°C and tempered at about 800°C after welding. If the weldment cannot be heat treated, the stainless steel flanged pipe fitting electrode (A107, A207) 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, fertilizer, petroleum, and medical machinery manufacturing.