To ensure the production quality of pressure vessels, it is essential for the personnel to rigorously inspect the quality of raw materials. After completing the material inspection, it is necessary to trace and inspect various stages such as material entry and production to ensure that the manufacturing process of pressure vessels complies with the process requirements. When controlling the quality of pressure vessels, it mainly involves the following aspects.
Manufacturing Process Control
The manufacturing of pressure vessels, unlike other products, follows the principle of manufacturing multiple varieties for a single set. Controlling the manufacturing process of pressure vessels involves incorporating specialized processes into each set of pressure vessels. After determining the manufacturing process, it is crucial to ensure pressure vessel production according to the process specifications. After completing each operation, specialized quality inspection personnel need to inspect the process flow and operational quality, ensuring qualification before signing on the process card and transporting the product and process card to the next operation.
Control of Pressure Vessel Material Quality
For the control of raw materials, it is essential to strictly adhere to the material selection based on design requirements, including material grades and corresponding standards. Personnel need to follow the process flow for material selection, procurement, acceptance, re-inspection, storage, and issuance. This ensures traceability of materials, guaranteeing their quality. Material procurement must be from units listed in the qualified supplier directory, and manufacturing units must regularly evaluate material suppliers. Material acceptance should include providing a quality certificate, with its contents consistent with the actual material identification. Strict adherence to standard requirements for re-inspection and marking transplantation is necessary to prevent material mixing. Given that pressure vessels are used in special environments and carry unique media, strict requirements are necessary for the physical, chemical, and mechanical properties of container materials.
Control of Pressure Vessel Deformation
Deformation during the manufacturing process of pressure vessels can lead to issues such as decreased overall stability, uneven stress distribution, affecting the overall quality of the container. Therefore, a rational process must be developed to avoid deformation of pressure vessels. For vessels with small wall thickness and large diameter, internal surface support is necessary to prevent deformation during transportation and welding processes. Material cutting requires post-cutting rectification of the material surface. During actual product manufacturing, strict adherence to riveting process requirements is necessary to avoid strong assembly, preventing stress concentration in certain areas. During welding, adjustments to welding parameters are necessary, considering process construction standards to prevent significant welding deformation. After welding, post-weld heat treatment is essential to control the deformation of the container to the maximum extent and eliminate residual stress caused by welding deformation.
Welding Quality Control
Welding is the most widely used production process in the manufacture of pressure vessels. Therefore, welding quality directly impacts the manufacturing quality of pressure vessels. To effectively control welding quality in the manufacturing of pressure vessels, the following measures can be taken.
Control of Welding Process
In China, a pre-welding process specification must be prepared before welding. Validation of the pre-welding process ensures compliance with the welding process. Wage assessment for welding is crucial, and welding process assessment is an important measure to ensure welding quality and a significant basis for guiding the preparation of welding operation instructions. The preparation of welding process assessment should be based on parameters such as pressure vessel material, thickness, welding method, and heat treatment. It should also ensure the coverage of welding process assessment on weldments. The welding person in charge should have high comprehensive abilities. Before welding, the welding engineer in charge should organize the preparation of welding process cards. For each weld seam, a reasonable welding process should be prepared based on factors such as material, specifications, and groove form as required by the drawings. Welders should strictly follow the welding methods and parameters specified in the welding process during welding.
Control of Welding Personnel
First, it should be ensured that welding personnel have professional technical qualifications, and safety education and training should be conducted before welding personnel are on duty. Considerations for site equipment, welding equipment, and other conditions are crucial during welding, choosing appropriate welders, and strictly prohibiting unauthorized or out-of-range operations. Welding personnel should undergo regular training for skill enhancement, with periodic assessments of their technical proficiency. Professional ethics of welding personnel are crucial for ensuring welding quality. It should be ensured that welding personnel strictly follow construction process standards in welding work, enhancing the welding performance of welding work effectively.
Control of Welding Equipment
Welding technical personnel should supervise the actual operation of welding equipment. If problems are identified in the operation of equipment, timely maintenance is necessary. Attention should also be given to the routine maintenance of equipment, checking the effectiveness of instruments and instruments, and conducting regular measurement and identification.
Control of Welding Materials
Control of welding materials mainly involves control from procurement, warehousing, drying, issuance, and recycling. Welding material procurement must also be supplied by qualified suppliers and should be regularly evaluated. During welding material acceptance, a focus should be on reviewing the welding material quality certificate, with necessary chemical composition and mechanical property retests if required.
Quality Control of Non-Destructive Testing Processes
Non-destructive testing is a crucial part of pressure vessel production, reflecting directly on whether welding quality is qualified. After completing the manufacture of pressure vessels, the corresponding non-destructive testing methods, testing ratios, and qualification levels should be adopted according to the design drawings. Testing should be conducted on the parts to be tested, and non-destructive testing of weld joints should be performed to ensure that there are no defects exceeding the standard in the weld. If there are defects exceeding the standard, timely rework should be performed on the defective parts. Rework process requirements should strictly adhere to the standard requirements. Many factors affect the quality of non-destructive testing. Currently, human factors generally play a dominant role in commonly used non-destructive testing methods. Therefore, improving the quality of non-destructive testing personnel and supervision of the non-destructive testing process are crucial. Secondly, non-destructive testing equipment should undergo regular verification and calibration to ensure that the testing instruments are in good and accurate condition.
Conclusion
The manufacture of pressure vessels is a complex production process. Irregularities or deficiencies in any part of the process can have an impact on the quality of pressure vessels. Therefore, during the manufacturing process, it is crucial to strictly adhere to quality control requirements and fully utilize the role of quality management measures. In addition, project responsibility engineers also need to rigorously inspect the quality issues in various process flows, record problems in detail during the process, and analyze problems in the use of process technology promptly. This facilitates optimization and improvement, ensuring the production quality of pressure vessels is guaranteed.
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