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Section 1 Inspection of Valve Castings and Forgings The inspection of valve castings and forgings mainly includes the following items. 1) Chemical composition 2) Mechanical properties 3) Quality of castings and forgings, mainly including the following items: ① Shape, dimensions, weight, and tolerances of castings ； ②Surface quality ； ③Defects and Handling ； ④Strength of pressure-bearing components ； ⑤Non-destructive testing quality. Section 2: Inspection of the Main Dimensions of Valves I. Inspection of the deviation in the structural length of valves The deviation in the structural length of valves is to be checked in accordance with the requirements specified in the table. II. Inspection of the deviation in the parallelism or perpendicularity of the flange sealing surfaces of flanged valves: The deviation in the parallelism or perpendicularity of these sealing surfaces shall be checked in accordance with the relevant requirements; for valves not specified in the table, the relevant design specifications shall apply. III. Inspection of the minimum wall thickness of valve housings – The minimum wall thickness for various types of valve housings. IV. Inspection of other key dimensions of valves: 1. Wear allowance of the sealing surface of gate valves; 2. Safety valve springs – 1) Deviation in the free height of the springs. 2) Deviation of the spring’s inner diameter. 3) The deviation in the spacing of the spring windings in the free state is as per the table. 4) The deviation in the deformation amount or stiffness of the spring shall not exceed 20% (the deviation values for symmetric or asymmetric distribution may be specified according to design requirements). 3. Other components: The dimensional inspection of other components is carried out in accordance with relevant standards and design specifications. V. Inspection of valve cleanliness Valve cleanliness refers to the degree of cleanliness inside the valve’s interior; it is determined by the amount of impurities and contaminants present on the surfaces of the valve’s interior (including the surfaces of all internal components). It is a key item for the quality inspection and grade evaluation of valve products. 1. Assessment criteria for cleanliness The assessment criteria for cleanliness are calculated using the following formula: 2. Inspection methods and requirements for cleanliness (1) The valves to be inspected should be those that have passed the manufacturer’s inspection and been approved for storage. The cleanliness check should be conducted before the product performance testing. (2) Disassemble all components inside the valve cavity; pressure fittings and connections that cannot be removed need not be taken apart. (3) The cleaning areas of each component show no obvious sand adhesion after cleaning. Before cleaning and inspecting the surfaces of each component, it is permissible to scrub other external surfaces that are not relevant. (4) The sieve should be dried before filtration; its initial mass should be measured, and it should be numbered along with records of its mass kept. (5) The cleaned liquid is filtered through a screen to collect impurities and dirt. (6) After filtration, the sieve together with the impurities and contaminants is placed in a drying oven at 105±℃ and baked for 1 hour; it is then allowed to cool naturally to room temperature before being weighed. (7) Results of the cleanliness check (amount of impurities and dirt).