Production of high-weldability steel for large-diameter pipe

The use of controlled rolling for coiled steels of type 05G1B — which are distinguished by their low carbon content (0.04–07%), economical alloying (Cr, Ni, Cu), and microalloying with niobium — ensures formation of the requisite set of characteristics in the coiled product: a combination of high strength with good weldability and cold resistance. This is achieved through the formation of a ferritic-bainitic structure with fine ferrite grains and dispersion-hardening of the steel by niobium carbonitrides. New high-weldability steel 05G1B can be recommended for use in the production of electric-welded large-diameter gas-line pipe of strength class K56.