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I. Introduction to ASME U Marking and Related Standards 1. Basic Information on ASME Codes – Definition and Organization: ASME stands for American Society of Mechanical Engineers. Related organizations also include NB (National Board of Boiler and Pressure Vessel Inspectors), AI A (ASME-authorized inspection body), and AI (authorized inspector). - Standard case: The version is updated every 3 years ； Supplements are published annually, with enforcement starting 6 months later ； Explanations are published by the ASME Code Committee and are not part of the code ； Standard cases are used to clarify disputes or provide additional requirements ； Corrections are enforced immediately. 2. Requirements for the enterprise responsible for documentation – Development of system documents: Establish a quality management system in accordance with ASME standards, and prepare manuals in both Chinese and English ； Prepare operational procedure documents. - Product design and manufacturing: Design prototype products in accordance with specifications, and provide English drawings and strength calculation reports ； Purchase materials that comply with ASME Section II codes ； Complete welding procedure qualification (PQR), welding procedure specification (WPS), and welder and welding operator skill qualification (WPQ) ； Manufacture demonstration products; after completing the welding of specific welds, they can be submitted for joint inspection. - Personnel and equipment calibration: Train and assess NDT personnel in accordance with the American Society for Nondestructive Testing SNT-TC-1A standard ； Meters used for ASME certification are calibrated in accordance with regulatory requirements. - Requirements for equipment personnel: Welding teams must be provided by the enterprise itself; some processes can be outsourced ； The relevant supervisors must be familiar with the relevant sections of the original ASME codes. 3. Differences between ASME and GB150/pressure vessel codes – Design responsibilities: ASME considers design to be part of the constructor’s tasks, whereas GB150 and the pressure vessel codes treat design as a separate entity, with a design license system in place. - Parameter setting: GB150 uses design pressure, temperature, thickness, etc. as the basic parameters ； ASME uses the maximum allowable working pressure (MAWP), minimum allowable design metal wall temperature (MDMT), nominal thickness, and effective thickness as the basic parameters. - User request: In China, there is a tendency for standards and specifications to clarify issues; design firms often use these standards and specifications as the final requirements ； Foreign users often put forward additional requirements based on standards. 4. Adoption of ASME standard codes: In the United States, Canada, Mexico and other countries, boilers and pressure vessels within certain categories are required to be designed, manufactured, inspected in accordance with ASME codes, and to bear stamp marks ； In areas outside the scope or outside North America, when required by the user or local government inspection authorities, it is also possible to apply a stamp in accordance with the specifications during manufacturing. 5. Related to U-shaped stamps – Relevant standards include: Technical Conditions for Material Type II (ferrous and non-ferrous metal materials, welding wires, electrodes, and filler metals; material properties), Non-Destructive Testing Type V, Pressure Vessels Type VIII (Volume 1: Rules for the Construction of Pressure Vessels), and Welding and Brazing Evaluation Type IX. - Stamp type: U-stamp used for manufacturing and installing fire-resistant pressure vessels constructed in accordance with Section I, Volume VIII of ASME ； The U2 stamp is used in Volume VIII, Part 2 ； The U3 stamp is used in Volume VIII, Part 3. II. Interpretation of the main tasks and requirements that certification companies must fulfill 1. Quality management system and document preparation – It is necessary to establish a quality management system in accordance with ASME standards, and to prepare quality management manuals in both Chinese and English. This serves as the foundation for standardized management, as well as an important document for demonstrating a company’s management capabilities to AI (authorized inspectors) and joint inspection teams. Develop operational procedure documents to guide the orderly conduct of various production activities within the enterprise. - Demonstration products are designed in accordance with ASME codes, and English version of the design drawings and strength calculations are provided to ensure that the product design meets the regulatory requirements and enables international reviewers to accurately understand the design intent and product performance parameters. 2. Product materials and welding-related aspects – Materials that meet ASME Section II specifications should be purchased; the source of these materials is not a concern as long as they comply with the specifications, which reflects the flexibility of the ASME standards regarding material selection. - In accordance with ASME Code Volume IX, Welding Procedure Qualification (PQR), Welding Procedure Specifications (WPS), and Welder and Welder’s Assistant Qualification (WPQ) are carried out. The welding work is performed by the company’s own welders, ensuring welding quality and process control. 3. Personnel and equipment-related – NDT personnel are trained and assessed in accordance with the SNT-TC-1A standard issued by the American Society for Nondestructive Testing. Level III personnel are responsible for training and certifying Level I and Level II personnel, to ensure that inspection staff possess the necessary professional skills to guarantee product quality. - Complete the manufacturing of the demonstration product; after welding specific welds, it can be submitted for joint inspection to verify the actual implementation of the quality management system. Calibrate measuring instruments in accordance with regulatory requirements to ensure the accuracy and standardization of production measurements. - Welding work is to be handled by the welding company itself; some processes can be outsourced ； The relevant supervisors need to be familiar with the corresponding sections of the original ASME codes. While oral communication skills are not required, they must possess the ability to read and understand professional codes in order to meet work-related and inspection requirements. III. Interpretation of ASME Joint Inspections 1. Main contents of joint inspections – Document and system review: Review the quality management manual to assess whether the company’s management system meets ASME code requirements and provide suggestions for improvement. - On-site inspection: Inspections are carried out at various locations such as the material storage area and the welding materials warehouse, in order to understand the actual conditions regarding the company’s management of production materials, the product manufacturing process, and the testing and inspection facilities. - Personnel and document review: Examine the design documents of the prototype product to assess the professional competence of the designers ； Review welding-related documents (PQR, WPS, WPQ) to assess the qualifications of welders and the implementation of welding procedures ； Review the qualification assessment for NDE personnel, conduct random checks on the qualifications of personnel at different levels, and evaluate the management capabilities of Level III NDE personnel. - Products and inspection checks: Examine the manufacturing process of sample products to ensure that production complies with standards ； Inspect the non-destructive testing laboratory, randomly check RT film and reports to ensure that the test results are accurate and reliable ； Check the calibration certificates of measuring instruments and their validity to ensure the accuracy of measurement data. 2. Joint Inspection Conclusion – Certification Recommendation: The enterprise’s quality management system and its actual implementation are satisfactory; the non-conformities have been rectified, and it meets the requirements of ASME codes, therefore certification is recommended. - It is recommended to issue the certificate after corrective actions are taken: Significant deficiencies were found during the inspection, and the company must address these issues within the specified time frame. Once confirmed by an AIA (ASME-authorized inspection body), the application can be submitted to ASME for approval of the certificate issuance. - It is recommended not to issue a certificate: there are non-compliant discrepancies that result in the failure or termination of the joint inspection; the enterprise must submit a new application 6 months after the failure of the joint inspection.