The most commonly used type of flange for connecting pipes in modern applications is the weld neck flange. It has a neck extension with a weld bevel at the end, which allows it to be butt-welded directly to the pipe, providing a secure and seamless connection. Weld neck flanges are especially popular in larger sizes and higher pressure classes. In fact, for many applications, they are the only type of bored flange used. If you had to choose just one type of flange for your piping system, the weld neck flange would be the preferred choice.