Interpretation of New Edition of State Specification Seamless Steel Pipe Used for Petroleum Cracking Process and Seamless Steel Pipe Used for High Pressure Fertilizer Equipment

The main revisions of new edition of state specification GB/T 9948-2013 Seamless Steel Pipe Used for Petroleum Cracking Process and GB/T 6479-2013 Seamless Steel Pipe Used for High Pressure Fertilizer Equipment are described and some interpretation and notes are made for the revisions in the specifications.In 2013 edition, emphatically, the permissible deviations of the steel pipe dimensions are revised, the delivery method for the smallest wall thickness is added, the model and chemical composition of steels are revised and added, the manufacture method and requirements of billet are regulated, the requirements for the mechanical properties of steel pipes are revised, the heat treatment system of steel pipes is revised, the requirements for the non destructive inspection are revised, the requirements for the intergranular corrosion test are added.The revised targets are basically identical with the international standard and are more definite to the technical requirements for goods delivery in the steel pipe manufacture enterprises.