Flanges made from plate materials are suitable only for which flange type?

Flanges made from plate materials are suitable only for which flange type?

• A. Weld neck flanges
• B. Slip-on flanges
• C. Blind flanges
• D. Socket weld flanges

Answer: (C)

The key idea here is that plate material used for flanges is suited to flat, hubless designs. A plate-flange stock is simply a flat disc with a bolt pattern cut into it and, for a blind flange, no through bore or integral hub. That makes it easy to fabricate from plate stock without needing the complex internal geometry or neck that other flange types require. Weld neck flanges rely on a welded neck that extends toward the pipe and a precise bore for alignment, usually forged or cast to ensure strength at the connection. Plate stock doesn’t provide that neck or the same structural integrity for high-stress piping joins, so it’s not appropriate. Slip-on flanges need a hub and a bore that the pipe slides into before welding. Creating a proper hub and bore from plate material is impractical and not common practice, hence plate flanges aren’t typically used for this type. Socket weld flanges require a socket into which the pipe end fits and is welded from inside. That internal geometry and the corresponding weld area demand materials and manufacturing methods (often forging or casting) that plate stock can’t reliably supply. Since a blind flange is just a flat plate used to seal a line, it matches plate material perfectly, enabling straightforward fabrication from plate stock and providing a solid sealing surface with bolt holes around the center.

The key idea here is that plate material used for flanges is suited to flat, hubless designs. A plate-flange stock is simply a flat disc with a bolt pattern cut into it and, for a blind flange, no through bore or integral hub. That makes it easy to fabricate from plate stock without needing the complex internal geometry or neck that other flange types require.

Weld neck flanges rely on a welded neck that extends toward the pipe and a precise bore for alignment, usually forged or cast to ensure strength at the connection. Plate stock doesn’t provide that neck or the same structural integrity for high-stress piping joins, so it’s not appropriate.

Slip-on flanges need a hub and a bore that the pipe slides into before welding. Creating a proper hub and bore from plate material is impractical and not common practice, hence plate flanges aren’t typically used for this type.

Socket weld flanges require a socket into which the pipe end fits and is welded from inside. That internal geometry and the corresponding weld area demand materials and manufacturing methods (often forging or casting) that plate stock can’t reliably supply.

Since a blind flange is just a flat plate used to seal a line, it matches plate material perfectly, enabling straightforward fabrication from plate stock and providing a solid sealing surface with bolt holes around the center.