GB/T 14976-2012 is the standard for stainless steel seamless pipes used in fluid transportation. This standard specifies the requirements for dimensions, appearance, weight, and other aspects of the steel pipes. The outer diameter of the pipes generally ranges from 15.8mm to 68.6mm, with wall thickness ranging from 2.5mm to 7.5mm. Additionally, the standard also provides detailed specifications for the surface quality, chemical composition, mechanical properties, and more.

Key Changes from GB/T 14976-2002:

Compared to GB/T 14976-2002, GB/T 14976-2012 has undergone significant changes. These include the addition of delivery methods based on minimum wall thickness, modified tolerances for pipe dimensions, deletion of marking examples, changes to steel grades and chemical compositions, introduction of new steel grades, removal of duplex steel grades and related content, modifications to hydrostatic test requirements for pipes, and the addition of informative Appendix A for grade comparison.

In conclusion, GB/T 14976-2012 sets the standard for stainless steel seamless pipes used in fluid transportation, outlining crucial requirements for dimensions, surface quality, chemical composition, and mechanical properties. The changes from the previous standard highlight the evolution and advancements in the industry, ensuring the quality and reliability of stainless steel seamless pipes.