A flat welding flange refers to a type of flange that is connected to a vessel or pipeline using a corner weld. It belongs to the general type of flanges. During design, it is checked as an integral or loose flange based on the degree of integration between the flange ring and the straight tube section. Flange rings come in two types: with neck and without neck. Compared to neck welding flanges, flat welding flanges have a simpler structure, use less material, but they are not as rigid or sealing as neck welding flanges. Flat welding flanges are widely used in the connection of medium and low-pressure vessels and pipelines.