Guobiao GB in the People’s Republic of China is the abbreviation of Guojia Biaozhun, meaning the “National Standards”, or Guojia Biaozhun Ma, meaning the “National Standard Encoding” as Chinese character encoding system. Both are issued by the Standardization Administration of China, the Chinese National Committee of the ISO and IEC.
View the main GB standard for steel pipes and pipe fittings as below:
GB/T18984-2003, Low-temperature heat exchanger tubes seamless steel pipe
GB/T18984-2003 standard suitable for -49 to -148 degrees F cryogenic pressure vessel piping, and low-temperature heat exchanger tubes seamless steel pipe.