Abstract: The present disclosure relates to a spheroidizing-annealed steel for the ball screw having high strength and resistance to low temperatures, wherein the chemical composition of the steel in mass percentage is: C: 0.40-0.70%, Si: 1.20-1.80%, Mn: 1.00-1.60%, Cr: 0.80-1.20%, S: ?0.025%, P?0.025%, Ni: 0.10-0.60%, Cu: 0.30-0.80%, Mo: 0.10-0.40%, Al?0.05%, Ca?0.0010%, Ti?0.003%, O?0.0010%, As?0.04%, Sn?0.03%, Sb?0.005%, Pb?0.002%, the balance is Fe and unavoidable impurities. In microstructure of the steel, cementite exists in a spheroidized state with a diameter of 0.1-0.5 ?m, preferably 0.3-0.5 ?m, a spheroidizing rate is 95% or more, and the rest is ferrite.

Abstract: A steel, including: between 0.45 and 0.70 wt. % of carbon, between 0.10 and 0.50 wt. % of silicon, between 0.30 and 0.70 wt. % of manganese, between 0.20 and 0.60 wt. % of chromium, less than or equal to 0.025 wt. % of phosphorus, between 0.003 and 0.030 wt. % of sulfur, less than or equal to 0.1 wt. % of molybdenum, less than or equal to 0.2 wt. % of nickel, less than or equal to 0.04 wt. % of aluminum, less than or equal to 0.3 wt. % of copper, less than or equal to 0.001 wt. % of calcium, less than or equal to 0.003 wt. % of titanium, less than or equal to 0.001 wt. % of oxygen, less than or equal to 0.04 wt. % of arsenic, less than or equal to 0.03 wt. % of tin.