Production Practice of Russian Standard-based Welding Process for K60 Linepipe

Analyzed is the weldability of the base metal of the Russian standard-based K60 linepipe，and elaborated are the main aspects concerning manufacture thereof，covering determination of welding material，design of the welding bevel，the welding process，and the product inspection results，etc. It is concluded by the coauthors that sufficient acicular ferrites in the structure will be obtained by means of using high basicity weld flux，and properly controlling contents of Mn and Si in the weld seam metal，and that the welding heat input remarkably affects the weld seam structure of the K60 linepipe，i.e.，along with increase of the welding heat input，proportion of the columnar crystal is reduced，while acicular ferrite is first increased，and then gradually decreased.