Ultrahigh-pulling-speed niobium-containing HRB400E deformed steel bar and production process thereof

The invention provides ultrahigh-pulling-speed niobium-containing HRB400E deformed steel bar and a production process thereof. The ultrahigh-pulling-speed niobium-containing HRB400E deformed steel barcomprises the following chemical components of, in percentage by weight, 0.16%-0.22% of C, 0.20%-0.50% of Si, 0.30%-0.60% of Mn, less than or equal to 0.025% of P and less than or equal to 0.025% ofS, less than or equal to 0.35% of Cr, 0.20%-0.40% of Mo, and the balance Fe and inevitable residual elements; and the specific production process comprises the steps of molten steel smelting, continuous casting, continuous casting billet heating and steel bar rolling. According to the method, through component optimization design and steelmaking, refining, continuous casting and steel rolling process optimization, the ubiquitous casting blank quality problem and the problem that steel leakage accidents cannot be guaranteed only when a casting machine is used for speed reduction production in the niobium-containing defo