This standard specifies the quality indicators, inspection methods and inspection rules for three levels of internal combustion engine powder metallurgy valve seat products: Level 1, Level 2 and Level 3. This standard is applicable to the inspection and assessment of product quality grading of insert-type powder metallurgy valve seats (hereinafter referred to as powder metallurgy valve seats) for reciprocating piston internal combustion engines with cylinder diameters less than or equal to 200mm. See the standard text for specific technical content.