DIN EN ISO 28721-4 (2015-05)被替代
Vitreous and porcelain enamels - Glass-lined apparatus for process plants Part 4: Quality requirements for glass-lined flanged steel pipes and flanged steel fittings (ISO/FDIS 28721-4:2015); German and English version FprEN ISO 28721-4:2015
出版：German Institute for Standardisation (Deutsches Institut für Normung)
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