HIGH-STRENGTH MICROALLOYED STEEL WITH HIGH VISCOSITY AT ULTRA-LOW TEMPERATURES WITHOUT NICKEL CONTENT AND METHOD OF ITS PRODUCTION Russian patent published in 2025 - IPC C22C38/02 C22C38/04 C22C38/12 C22C38/14 C21D8/02 C21C7/06 C21C5/30 C21C5/52 

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, namely to cryogenic high-strength microalloyed steel used for the manufacture of parts of equipment for the production of liquefied hydrocarbon gases, ammonia, liquid oxygen and nitrogen, vessels for their storage and pipelines for transportation, as well as equipment operating in severe frost conditions. Steel has a composition which includes the following chemical components in wt.%: 0.011<C<0.099, 0.051<Si<0.24, Mn: 1.21-1.49, Nb: 0.031-0.059, Ti: 0.009-0.016, Zr: 0.001-0.018, RE: 0.001-0.018, Fe and unavoidable impurities are the rest. Weight percentage of C and Si satisfies expression Si/C = 1-8, and the weight percentage of the Zr element and the RE element simultaneously satisfies expressions 0.010%<Zr+RE<0.019% and Zr/RE=1-6.

EFFECT: steel has high viscosity at ultralow temperatures.

10 cl, 5 dwg, 1 tbl