Seal washers are used as sealing components in mechanical and equipment applications, as well as in pipelines where fluids are present. They serve as sealing materials both internally and externally. Seal washers are made from metal or non-metallic sheet materials, which are cut, stamped, or trimmed into shape, and are used for sealing connections between pipes and for sealing connections between parts of machinery and equipment. They can be categorized into metal and non-metal seal washers. Metal types include copper washers, stainless steel washers, iron washers, aluminum washers, etc. Non-metal types include asbestos washers, non-asbestos washers, paper washers, rubber washers, etc.