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Control in the material procurement process: Prepare a material ordering list. The material ordering list should be prepared by the technical department of the manufacturing unit after reviewing the drawings. The contents of the material order sheet should include the name of the material, its material type, specifications, weight or quantity, material standards, special performance indicators of the material, design requirements beyond the current standards for the material, requirements for re-inspection of the material, and specimens to be provided for re-inspection of forgings. The material order sheet must also bear the signatures of the person who submitted it, the person who checked it, and the person who approved it. Review the material order list. After receiving the material order list, the procurement department should review it to ensure that all information is complete and that all signatures are present. Any special requirements or unclear points should be discussed promptly with the design department before a purchase contract can be signed (the supplier should be an external party that has passed the quality assessment conducted by the manufacturing unit). Control at the material arrival stage: After the materials are purchased and arrive at the factory, purchasing staff and material inspectors should carry out inspection in accordance with the purchase contract following these steps: Review of the material quality certificate. 1) The content of the material quality certificate must be complete and clear, and it must bear the quality inspection seal of the manufacturer of the materials. 2) When obtaining materials for boilers and pressure vessels from non-material manufacturing units, the original quality certificate provided by the material manufacturing unit or a copy stamped with the inspection seal of the material supplier and the signature of the responsible person shall be obtained. 3) The markings on the quality certificate for materials specific to boiler and pressure vessel applications should also include the manufacturing permit mark and the permit number. 4) Whether the various performance parameters of the material meet its material standards as well as the specific requirements specified in the order contract. Inspection of material quantity, appearance, and surface: 1) Verify the material quantity one piece at a time. 2) Verify each product’s identification one by one, as well as the consistency between the product identification and the material quality certificate. 3) Measure each item one by one to check whether its specifications match those stated in the quality certificate and whether the thickness deviation is within acceptable limits. 4) Inspect each item one by one to check for any defects such as cracks or rust that do not meet the standards. Re-inspection of materials: For materials that pass the re-inspection, records of the re-inspection results must be kept, and the re-inspection report should be attached to the corresponding quality certificate, so as to enable archiving of the material documentation and use for product certification purposes ； For materials that fail re-inspection, the material supplier should be contacted promptly; once both parties confirm there are no errors, the corresponding procedures for handling defective items shall be followed. Control over the material identification and transfer process is intended to ensure the quality and safety of each pressure vessel, as well as to enable the tracking of each steel plate or batch of steel pipes. Qualified materials go through the warehousing procedures as specified. At this stage, the relevant department of the manufacturing unit shall provide the material’s identification number (for pipes, a color code should also be provided). The method for assigning these identification numbers (or color codes) is outlined in the manufacturing unit’s quality assurance manual. With the material bearing the transfer number (color code), the material supervisor marks it separately on its quality certificate and at the designated locations on the material. Mark transplantation should be performed on the material before segmentation. Control of material storage: Materials should be stored in designated areas. These storage areas should be divided into a \"waiting for inspection area\", a \"qualified products area\", and a \"unqualified products area\"; they should also have covers. In the case of temporary storage outdoors, measures must be taken to prevent corrosion and rust. For areas where stainless steel materials are stored, softening treatments should be applied. The materials in the storage area should be stored neatly and labeled according to different types (such as sheets, pipes, etc.) and specifications. The material labels must indicate the type, material composition, specifications, and identification code (color code) of the materials. Ensure that each transferred account corresponds to one sign. Control in the process of maintaining material accounts: Each manufacturing unit should keep accounts for materials. These accounts should be separate from financial accounts, and they cannot be simple transaction logs or accounts specific to individual products; such accounts do not constitute proper material management accounts. A separate account for proper material management should be maintained, along with an index that includes the original information about the materials (material name, specifications, manufacturing standards, manufacturer, certificate of quality number, batch number from the furnace, supply status, transfer number, supplier, etc.) as well as records of receipt and issuance (date, quantity received, quantity issued, destination of the materials, inventory level, signature field for the person who took the materials, order number, etc.). When the inventory on each account page is zero, newly purchased materials of the same name and specifications should be assigned to a new account page based on their material transfer number; the original account page cannot be used, as this would make it difficult to track the materials. Control in the material distribution process: The basis for distributing materials is the material order list and the material requisition form. Material requests are generally filled out by the production workshop based on the manufacturing process (the form includes details such as the name of the material, specifications, quantity, intended use, name of the component, part number, etc.). The material requisition form must be prepared in at least three copies: one copy is kept by the warehouse, numbered according to the requisition number ； A copy is filed by the quality inspection department by product number, to serve as the basis for the material list when issuing product quality certificates ； One copy is kept in the material receipt department as proof of the material distribution recorded in the process transfer card. In the event of material substitution, the material supervisor must also keep the relevant substitution records to ensure the correctness of subsequent manufacturing processes and the use of welding materials. After the materials are distributed according to the procedure, the material custodian must update the accounts promptly based on actual usage, to ensure that the records for each material identification number always match the actual items. Control in the material transfer process: After the materials are delivered to the production workshop, product codes must be marked on them to prevent mixing. Mixing of different materials should be controlled throughout the entire production process, and workshop inspectors must record the transfer number of each major pressure-bearing component on the process flow card. Before conducting the hydrostatic test on the product, the inspectors must ensure that the material receipt form (or a substitute material form if substitution is used), the process flow card, and the identification number on the product are all matched. Any available surplus material should be promptly communicated to the materials custodian and returned to the warehouse for storage in accordance with the relevant regulations.