This is similar to a slip-on flange in outline, but the bore is counter-bored to accept pipe. The diameter of the remaining bore is the same as the inside diameter of the pipe. The flange is attached to the pipe by a fillet weld around the hub of the flange. An optional interval weld may be applied in high stress applications. It’s biggest use is in high pressure systems such as hydraulic and steam lines.  

This is similar to a slip-on flange in outline, but the bore is counter-bored to accept pipe. The diameter of the remaining bore is the same as the inside diameter of the pipe. The flange is attached to the pipe by a fillet weld around the hub of the flange. An optional interval weld may be applied in high stress applications. It’s biggest use is in high pressure systems such as hydraulic and steam lines.