Stainless steel flange in the use of precautions

1. Stainless steel flange, in order to improve the corrosion resistance and weldability and add appropriate stability elements Ti, Nb, Mo, etc., the weldability is better than that of chrome stainless steel flange. When using the same type of chrome stainless steel flange electrode (G302, G307), it should be preheated above 200℃ and tempered about 800℃ after welding. If the weldment cannot be heat treated, stainless steel flange welding rod (A107, A207) should be used.

2. 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 the carbon steel electrode, the arc should not be too long, the fast cooling between the layers, and the narrow welding passage is appropriate.

3. The electrode should be kept dry when used, titanium-calcium type should be dried at 150℃ for 1 hour, low a hydrogen type should be dried at 200-250℃ for 1 hour (can not be repeatedly dried, otherwise the drug skin is easy to crack and flake), to prevent the electrode drug skin sticking oil and other dirt, so as not to increase the carbon content of the weld and affect the quality of the weldment.

4. During welding of stainless steel flange fittings, carbides are precipitated by repeated heating, which reduces corrosion resistance and mechanical properties.

5. Chrome stainless steel flange fittings after welding hardening of the American standard flange is larger, easy to crack. If the same type of chromium stainless steel electrode (G202, G207) welding, must be preheated above 300℃ and after welding about 700℃ slow cooling treatment. If the welds cannot be heat-treated after welding, stainless steel flanged tube electrodes (A107, A207) should be selected.

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