Basic knowledge of flanges
Flange is a device that connects pipes or instruments, and plays the role of connection and fixation. Common flanges are made of round steel, and the shapes are divided into flat plates, blind plates, high necks, and flat welds. Production methods are divided into forging and casting. The material is mostly carbon steel or stainless steel.
Because flanges are used to connect pipes or equipment, they need to be able to withstand pressure. The flange pressure is divided into several levels in the world to achieve the minimum cost and maximum pressure capacity. For example, the American system standard classifies flanges by pounds (LB): 150LB 30OLB 40OLB 60OLB 90OLB 1500LB 2500LB, etc. The European system uses PN to express the pressure: PN6 PN10 PN16 PN25 PN40 PN63 PN100, etc. The Japanese system standard uses K to express the pressure: 5K, 10K, 16K, 20K, etc.
The internationally common pipe flange standards can be summarized as two different and non-interchangeable pipe flange systems: one is the European pipe flange system represented by Germany; the other is the American pipe flange represented by the United States system.