Butt-weld flanges can connect pipes to maintain the sealing performance of the pipes. Butt-weld flanges facilitate the replacement of pipe sections, easy disassembly and inspection of pipe conditions, and easy sealing of carbon steel pipe sections. Flanges are the connection of two large-diameter pipes. This equipment is also known as a carbon steel flange, usually consisting of two flange parts and several fastening bolts.

Carbon steel flanges are made of carbon steel. Low carbon steel has good plasticity and low strength. Adding an appropriate amount of carbon will harden, while plasticity will reduce strength. Flange connections may need to withstand higher tensile, compressive, torsional, and shear strengths. Therefore, butt-weld flanges are a better choice.

Precautions for using butt-weld flanges:

1. To prevent intergranular corrosion caused by heating butt-weld flanges, the welding current should not be too large, about 20% smaller than the carbon steel welding rod, the arc should not be too long, the intermediate layer should be cooled quickly, and the weld should be narrow. The electrodes should be kept dry. 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 (cannot be repeatedly dried, otherwise the coating is easy to crack and peel off) to prevent the electrode coating from adhering to oil and other dirt, to avoid increasing the carbon content of stainless steel and butt-weld flanges in the weld, which will affect the weld quality.

2. During the butt welding of butt-weld flanges, repeated heating will cause carbide precipitation, thereby reducing corrosion resistance and mechanical properties. After the chromium stainless steel welded flange is hardened, the American standard flange is large and easy to crack. When butt welding with the same type of chromium stainless steel welding rod (G202, G207), preheating slow cooling of more than 300 times and more than 700 times should be carried out.