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DE??? ?? ??
?? 3??? ??? ?? ??? ??? ??? ??.
?? ???? ??? ?? ??? ??? ??? ??? ????: ?? ??, ?? ??.
General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China, ??? ?? ??
Professional Standard - Ferrous Metallurgy, ??? ?? ??
British Standards Institution (BSI), ??? ?? ??