Studded tees and crosses are types of fittings that are used to connect pipes of different sizes and orientations. They are typically used in piping systems that require a branch connection at a specific location.

Studded tees and crosses are called “studded” because they have studs or threaded rods welded onto the flange faces. These studs are used to secure the flange to the piping system using nuts and washers.

The use of studded tees and crosses provides several advantages over other types of branch connections, including:

1. High Strength: The studs provide a strong and secure connection between the flange and the piping system.

2. Easy Installation: The use of studs and nuts makes installation of the fitting faster and easier than other types of branch connections.

3. Flexibility: Studded tees and crosses can be used to connect pipes of different sizes and orientations, providing greater flexibility in piping system design.

Studded tees and crosses are typically made of carbon steel, stainless steel, or alloy steel, and are available in a variety of sizes and pressure ratings. They are commonly used in the oil and gas, petrochemical, and power generation industries, where high-pressure and high-temperature applications are common.