Replace components of American or German standards with those that meet national standards
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I’ve encountered a problem recently: for equipment purchased from abroad, flange fittings and similar components are required to meet domestic standards. This means it’s necessary to determine whether the standard components available under domestic standards can be used in conjunction with foreign standards. However, I have a question: since there are many manufacturers in China that produce components according to foreign standards, and these components can be easily obtained, why is it still necessary to convert them into components that meet domestic standards? There is another issue: last week the company ordered some equipment that required ASME-grade materials, but the manufacturer used materials that meet national standards instead. Will this have any impact? Does the company definitely require the manufacturer to provide evidence? Is it necessary? I think that even if ASME standards are used, it’s still domestic production technology; there shouldn’t be any difference. Last edited by laiqi on 2009-3-6 14:43.]
Domestic flange standards are quite complex; in addition to the national standard GB, there are the HG standards issued by the former Ministry of Chemical Industry, as well as the SH standards from Sinopec. Even older standards such as JB exist as well. These standards were not specifically developed for the design, production, and sale of flanges. It’s hard to clarify things, but from what I understand, in the petrochemical industry, those involved in chemical processing tend to prefer the HG standards, while those working in oil refining prefer the SH standards. Domestic standards are also based on international standards; taking the HG standards as an example, they are divided into the European system, the American system, etc. Attached are some common standards: ● American standard: ANSI B16.5 Class150, 300, 600, 900, 1500 (WN, SO, BL, TH, LJ, SW) ● Japanese standard: JIS 5K, 10K, 16K, 20K (PL, SO, BL) ● German standard: DIN2573, 2572, 2631, 2576, 2632, 2633, 2543, 2634, 2545 (PL, SO, WN, BL, TH) ● Chemical industry standards, European system: HG20592-97 (HG20593-97～HG20614-97) ● Chemical industry standards, American system: HG20615-97 (HG20616-97～HG20635-97) ● Standards set by the Ministry of Chemical Industry: HG5010-52～HG5028-58, HGJ44-91～HGJ65-91 ● Sinopec standards: SH3406 ● Standards set by the Ministry of Machinery: JB81-59～JB86-59, JB/T79-94～JB/T86-94 ● **Standard: GB9112-88 (GB9113·1-88～GB9123·36-88) ● Standards for pressure vessel flanges: JB1157-82～JB1160-82, JB4700-2000～JB4707-200
1. If the equipment is exported and a substitute is used, an application for substitution must be submitted to check whether there are corresponding substitution provisions in ASME. 2. Even if the equipment is used domestically, a substitution form should still be provided, as different standards result in different prices – domestic standards result in lower costs, while ASME-standard materials are more expensive. Only by insisting on this can subcontractors be strictly controlled and speculative behavior prevented. 3. The flange standards set by the Ministry of Chemical Industry come in metric and imperial versions; the imperial version is completely compatible with ASME flanges