Differences between Flat Weld Flange and Butt Weld Flange

Nov 19, 2015

Because of high production efficiency, easy operation and reasonable price, flat weld flange and butt weld flange are most common weld flanges. In most cases, people will choose these two kinds of flanges. But how to distinguish them and what is the difference?

First, different material. Flat weld flange use ordinary steel plate as the material while butt weld flange use forged steel for manufacturing.

Second, different pressure. Nominal pressure for flat weld flange is between 0.6Mpa to 4MPa. Compared with flat weld flange, nominal pressure for butt weld flange is smaller.

Third, different welding connection, and this is the biggest difference. The flat weld flange has a socket RF with the diameter bigger than the pipe, so that the pipe can be inserted and welded inside. The butt weld flange’s wall thickness and diameter are required to be the same with the pipe, so that both the inside and outside of the weld seam can be welded up.

Fourth, different steel degree. Flat weld flange has bigger steel degree than butt weld flange. But when it comes to strength, butt weld flange is higher with less leakage problem.