This standard specifies the technical specifications for mild steel Cardboard, which is applicable to gaskets for sealing joints in internal combustion engines such as aircraft, automobiles, and tractors. The standard refers to a series of relevant standards, including sampling, quantification, thickness, tensile strength, moisture, and other determination methods. Mild steel Cardboard is divided into A and B grades according to its use. Class A is suitable for aircraft engines, and Class B is suitable for engines such as automobiles and tractors.