Stainless steel flange is a kind of disc-shaped parts, which is the most common in pipeline engineering. Stainless steel flanges are used in pairs and with the supporting flanges on the valve. In pipeline engineering, stainless steel flange is mainly used for pipeline connection. In the pipeline that needs to be connected, various devices have a flange.
Comparison between stainless steel flange and carbon steel flange:
1. The thermal conductivity of stainless steel flange is low, about 1 / 3 of that of carbon steel. In order to prevent eye corrosion due to 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, and the interlayer should be cooled quickly. Narrow weld bead is preferred. 2. High electro negative rate, about 5 times that of carbon steel. 3. The large linear expansion coefficient is 40% larger than that of carbon steel, and the value of linear expansion coefficient increases accordingly with the increase of temperature.
When welding stainless steel flanges, the welding rod shall be kept dry, 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 oil and other dirt on the electrode coating, so as to avoid increasing the carbon content of the weld and affecting the quality of the weldment. When flange pipe fittings are welded, carbides are separated by repeated heating, which reduces corrosion resistance and mechanical properties. After welding, the hardening of chrome flange pipe fittings is large, and the American standard flange is easy to crack. If the same type of chromium stainless steel electrode (gg207) is selected for welding.
