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Chapter 1 General Provisions Article 1 These regulations are formulated in order to improve the quality of stainless steel pressure vessel manufacturing and ensure their safe use. Article 2: The manufacture of stainless steel pressure vessels shall, in addition to complying with GB150 \"Steel Pressure Vessels\", GB151 \"Steel Shell and Tube Heat Exchangers\", the \"Regulations on Safety Supervision of Pressure Vessels\", as well as the design drawings and relevant technical requirements, also comply with the provisions of these regulations. Article 3 These provisions apply to the manufacturers of stainless steel pressure vessels. The manufacture of stainless steel containers at normal pressure may be carried out in accordance with these regulations. Chapter 2 Materials Article 4 The stainless steel materials and welding materials used in the manufacture of pressure vessels shall comply with the corresponding ** and industry standards. In addition to meeting the relevant foreign regulations regarding the technical properties of imported materials, they must also comply with China’s relevant standards and specifications. Its quality certificate shall be provided by the material manufacturer, and its contents must be complete and accurate. Article 5: For stainless steel materials used in the manufacture of the main pressure-bearing components of pressure vessels of Classes I and II, if the quality certificate does not contain all necessary information or the markings on the actual products are unclear, necessary inspections or tests must be carried out to determine that the grade of the material meets the corresponding quality standards before it can be used. For stainless steel materials used to manufacture the main pressure-bearing components of category III pressure vessels, in addition to undergoing necessary retests for chemical composition, mechanical properties, and bending properties as required, those materials for which resistance to intergranular corrosion is essential must also have their intergranular corrosion resistance tested. Article 6: If stainless steel materials are to undergo retesting for intergranular corrosion, the testing shall be carried out in accordance with GB4334 \"Test for Intergranular Corrosion of Stainless Steels\" or GB1223 \"Test Methods for Intergranular Corrosion Susceptibility of Stainless and Acid-Resistant Steels\", unless otherwise specified in the design drawings. Article 7: The stainless steel used for manufacturing pressure vessels shall be free from delamination, and the surface shall not have cracks or scars. The surface of the stainless steel sheets supplied after pickling must be free of scale and over-pickling. Article 8: Stainless steel raw materials shall be stored indoors, classified by steel grade, specification, and furnace batch number. And strict isolation measures are in place from carbon steel materials. Article 9: Stainless steel materials shall have clear incoming inspection marks. This marking should be made using a meta-chlorine sulfur-free marker; stamping is not allowed, nor are any polluting materials such as paint. Chapter 3 Manufacturing Environment Article 10 The manufacturing of stainless steel pressure vessels shall take place in a separate, enclosed production workshop or a dedicated fixed production site, and such areas must be strictly separated from those used for carbon steel products. If a stainless steel pressure vessel is equipped with carbon steel components, those components shall be manufactured separately. Article 11: To prevent contamination by iron ions and other impurities, the production areas for stainless steel pressure vessels must be kept clean and dry, with dust strictly controlled. The floor should be covered with rubber or wooden pads. Special roller frames, lifting fixtures, and tooling equipment should be used in production. Article 12: During the manufacturing of stainless steel pressure vessels, operators shall wear soft rubber work shoes, and the soles of these shoes must not contain any sharp objects such as nails. Article 13: Stainless steel components shall be placed on wooden stacking racks and must not be stacked arbitrarily. During the handling and transportation of stainless steel components, necessary transportation tools should be used to prevent contamination by iron ions as well as scratches and dents. Article 14: Stainless steel materials may be subjected to hot working only after impurities such as grease and paint have been removed. The sulfur or sulfide content in the atmosphere of the heating furnaces used in hot forming or heat treatment processes must comply with relevant standards. Article 15: The surface treatment of stainless steel pressure vessels shall be carried out in a dedicated area, equipped with necessary safety protection measures. Chapter 4 Processing, Shaping, and Welding Article 16: When cutting stainless steel plates, they should be moved to a dedicated area for cutting; it is strictly prohibited to cut them directly on piles of stainless steel materials. During processing, it is strictly prohibited to use steel needles to make marks or drill holes on the surface of the stainless steel material. Article 17: The transplantation marks and inspection confirmation marks for stainless steel materials shall be written on the stainless steel plates using chlorine- and sulfur-free marker pens, and written records of the material cutting shall also be kept. During the manufacturing of stainless steel pressure vessels, if it is found that the material markings are unclear, they must be corrected promptly after verification. Article 18: Stainless steel plates shall be cut using plasma cutting or mechanical processing. When using mechanical cutting for material removal, the machine tool should be cleaned thoroughly. When rolling stainless steel sheets into circles, the rolling machine should use iron-ion-free materials to cover the surface of the rollers. Article 19: When hot-forming stainless steel end caps, it is necessary to control the temperature inside the furnace, strictly regulate the initial and final pressing temperatures, and keep proper records. Heating in the same furnace as carbon steel heads is not allowed. Article 20: For stainless steel end caps, elbows, forgings, and other components that have been formed through heat treatment and for which resistance to intergranular corrosion is required, solution treatment or stabilization treatment must be carried out. Records of the heat treatment process, as well as temperature-time curves for such treatment, must be kept. Article 21: Wedges, shims, and other tools that come into contact with the surface of the housing during the housing assembly process should be made of stainless steel suitable for the housing. Forcing the assembly of stainless steel pressure vessels is strictly prohibited. Tools that may cause iron ion contamination must not be used during the assembly process. Holes in the cylinder body of stainless steel pressure vessels should be made using plasma cutting. Article 22: Stainless steel pressure vessels shall undergo welding procedure qualification in accordance with the JB4708 standard \"Welding Procedure Qualification for Steel Pressure Vessels\", and a welding procedure shall be developed based thereon. Welders working on stainless steel pressure vessels must possess the appropriate welding qualifications. Article 23: For stainless steel pressure vessels requiring resistance to intergranular corrosion, welding procedure specifications must be strictly followed during welding, and the temperature between weld layers must be tightly controlled. When cleaning the root of the weld bead, the carburized layer should be polished clean. The weld bead in contact with the working medium should generally be welded last. Article 24: When welding stainless steel pressure vessels, carbon steel shall not be used as a ground wire; the ground wire must be firmly attached to the workpiece, and spot welding for fixation is prohibited. Article 25: When welding stainless steel pressure vessels, it is necessary to use acetone or alcohol to clean off oil and other contaminants from the joints. Grooves made by plasma cutting should be polished to a metallic shine. During welding, it is not allowed to strike an arc directly on the un-welded surfaces of stainless steel. When using shielded metal arc welding, a splash guard coating covering an area of 100 mm on each side of the joint should be used to facilitate the removal of spatter. Article 26: The number of times welds on stainless steel pressure vessels can be repaired shall be strictly controlled; where resistance to intergranular corrosion is required, the original requirements shall still be maintained after the welds are repaired. Article 27: Welding test plates for stainless steel pressure vessel products shall undergo intergranular corrosion testing in accordance with the requirements of the design drawings, unless otherwise specified in those drawings. The methods for intergranular corrosion testing and the criteria for inspection shall be carried out in accordance with Article 7. Article 28: When manufacturing stainless steel pressure vessels, it is necessary to avoid scratches on the surface of the stainless steel caused by sharp or hard objects. If work needs to be carried out inside the vessel, protective measures such as using liners should be taken. Article 29: If there are local defects on the surface of stainless steel pressure vessels such as dents or scratches that affect their corrosion resistance, they must be polished. Article 30: The nameplate holder of stainless steel pressure vessels shall be made of a material of the same grade as that of the vessel body. Chapter 5 Surface Treatment Article 31 The surface treatment of stainless steel pressure vessels shall be carried out in accordance with the requirements of the design drawings. Article 32: Before the surface treatment of stainless steel pressure vessels, all welding repairs must be completed, and impurities such as welding spatter, slag, scale, weld marks, pits, and oil stains on the vessel’s surface must be thoroughly removed. During the surface treatment process, it is prohibited to use carbon steel brushes to clean the surface of stainless steel pressure vessels. Article 33: When mechanical polishing is used, chromium oxide in alumina should generally be selected as the polishing abrasive; iron sand shall not be used as an abrasive. It is strictly prohibited to mix abrasives of different particle sizes; a grinding wheel can only have abrasives of one single particle size bonded to it. After bonding the abrasive to the grinding wheel, the drying temperature and drying time must be strictly controlled depending on the type of abrasive used. Article 34: The polishing grade shall be increased step by step in sequence. After the rough polishing, a 10x magnifying glass should be used to inspect the surface; if small spots are found in certain areas, those spots must be polished clean before proceeding with the fine polishing. After abrading the small pitting in the local area, no obvious pits are allowed. Article 35: Throughout the polishing process, the polishing temperature must be continuously controlled to prevent deformation and overheating, and attention should be paid to the consistency of the polishing pattern. The polishing grade is evaluated in accordance with the design drawings and the requirements of GB1031 \"Surface Roughness\". Article 36: When using electropolishing or other methods for polishing, process tests shall be conducted in advance, and the polishing of workpieces must be carried out strictly in accordance with the process requirements. Article 37: The acid washing and passivation of stainless steel pressure vessels shall primarily be carried out by immersion; the wet wiping method or the application of paste can also be used. Article 38: Before acid washing and passivation, process tests must be conducted to determine appropriate formulations and operating procedures. The pickling and passivation solution should be sampled for testing on a regular basis to adjust its concentration in a timely manner. Article 39: Where there are carbon steel components on stainless steel pressure vessels, acid washing of those carbon steel components should be avoided as much as possible; if it is unavoidable, protective measures must be taken for the carbon steel components in advance. Article 40: The surface of stainless steel after pickling shall show no obvious signs of corrosion, nor any uneven color patterns; the surfaces that have been welded or heat-treated shall not exhibit any oxidized colors. After pickling stainless steel pressure vessels, they must be rinsed thoroughly with water; no residual pickling solution is allowed. The passivated stainless steel surface should be rinsed with water, and once it is neutral, the water droplets should be dried off. Article 41: After surface treatment, stainless steel pressure vessels that require resistance to intergranular corrosion must undergo a passivation film inspection. Inspect the passivation film in accordance with the specifications in the design drawings; if no such specifications are provided, use the blue dot method for inspection. The inspection of the passivation film should be avoided on the surface in contact with the medium. Article 42: Acid wash liquid that needs to be discharged shall undergo neutralization measures, and may be discharged only after meeting the **relevant discharge standards. Chapter 6 Pressure Testing and Packaging and Transportation Article 43 After the manufacture of stainless steel pressure vessels is completed, pressure resistance tests and airtightness tests shall be carried out in accordance with the requirements of the design drawings. Article 44: After a stainless steel pressure vessel has undergone a hydrostatic test, the water must be drained immediately, and any traces of water must be dried off. If it is not possible to dry off water stains due to structural reasons, the chloride content in the test water must not exceed 25 ppm. Article 45: During the pressure test, airtightness test, and packaging of stainless steel pressure vessels, if the passivation film on the surfaces in contact with the medium is damaged, measures should be taken promptly to re-passivate those surfaces. Article 46: After the manufacture of stainless steel pressure vessels is completed, all sealing surfaces and pipe ends shall be promptly covered with covers, and appropriate protective measures shall be taken. The carbon steel parts of the equipment should be painted. Unless required by the design drawings, the stainless steel surface generally does not need to be painted for protection. Article 47: When transporting stainless steel pressure vessels, necessary measures must be taken to prevent iron ion contamination and damage to the surface of the equipment. Chapter 7 Supplementary Provisions Article 48 These provisions shall be interpreted by the Ministry of Chemical Industry. Article 49 These provisions shall come into force as of the date of issuance.