A flat welding flange refers to a type of flange that is connected to a vessel or pipeline using angular welds. It falls under the category of general flanges. During design, it is checked as an integral or loose flange based on the degree of integrity between the flange ring and the straight cylindrical section. Flange rings come in two types: with a neck and without a neck. Compared to necked welding flanges, flat welding flanges have a simpler structure, use less material, but are not as rigid or sealed as necked welding flanges. Flat welding flanges are widely used for connecting medium and low-pressure vessels and pipelines.