Forged carbon steel flanges can be cast, threaded, or welded together. A flange connection consists of a pair of flanges, a gasket, and several bolts and nuts. The gasket is placed between the sealing surfaces of the flanges, and after the nuts are tightened, the surface pressure on the gasket reaches a certain value of 128, causing it to deform and fill the uneven areas on the sealing surface, ensuring a tight and leak-proof connection. Flange connection involves fixing two pipes, fittings, or equipment to separate flange discs first, adding a flange gasket between the two discs, securing them together with bolts, and completing the connection. Some fittings and equipment come with a flange disc and also fall under flange connections. Flanges are divided into threaded (screwed) flanges and焊接 flanges (welded flanges), which are made of steel. Low-carbon steel has good plasticity and low strength; adding an appropriate amount of carbon makes it hard, reducing plasticity and increasing strength. Flange connections that require high tensile, compressive, torsional, and shear strength may opt for carbon steel flanges.