Usage:
1. Purpose of connection: Mainly used to connect the ends of two metal pipes, valves, and equipment to form a detachable connection. It is one of the most common connection methods in industrial piping systems.
2. Paired use: Must be used in pairs (one piece is welded to one pipe end/equipment, and the other piece is welded to the other pipe end/equipment).
3. Connection process:
Fix the two metal flanges to the pipe or equipment ports by welding.
Place suitable metal spiral wound gaskets, asbestos rubber gaskets, polytetrafluoroethylene gaskets, etc. between the flange sealing surfaces.
Align the bolt holes.
Insert the bolts and nuts and tighten them evenly in a diagonal cross sequence to the specified torque.

Installation precautions:
1. Welding quality (butt welding/socket welding): For WN and SW type flanges, welding must be performed by qualified welders in accordance with specifications to ensure full penetration, no defects such as slag inclusions and pores, and perform necessary non-destructive testing. Heat treatment may be required after welding (depending on the material and wall thickness). For threaded flanges, ensure that the threads are intact, tightened in place and sealed. The quality of the flange or welding ring should be ensured for the slip-on flange.
2. Flange surface protection: It is very important to protect the sealing surface (FF, RF, MF, T/G, etc.) to avoid damage. Minor damage can be repaired with fine sandpaper or oilstone, and serious damage needs to be replaced.
3. Concentricity and parallelism: When welding or installing, ensure that the flange is perpendicular to the pipeline axis and the two flanges are strictly parallel and concentric.
4. Bolt tightening: Use bolt washers of the correct material, grade, and length. Strictly tighten in steps and evenly in a diagonal cross sequence to the specified torque. Using a torque wrench is the key. Considering thermal expansion, high-temperature systems need to be tightened again in a hot state.
5. Gasket selection and installation: Strictly select the correct type and material of gaskets according to pressure, temperature, and medium. Ensure that the gasket is of appropriate size, clean, and centered. It is strictly forbidden to use gaskets with an inner diameter smaller than the pipe diameter.
6. Flange standard and matching: Ensure that the size standard, pressure grade, and sealing surface type of the matching flanges are fully matched.