Spheroidizing annealing steel for low-temperature-resistant high-strength ball screw and manufacturing method of spheroidizing annealing steel

Abstract

The steel comprises the following chemical components in percentage by mass: 0.40 to 0.70 percent of C, 1.20 to 1.80 percent of Si, 1.00 to 1.60 percent of Mn, 0.80 to 1.20 percent of Cr, less than or equal to 0.025 percent of S, less than or equal to 0.025 percent of P, 0.10 to 0.60 percent of Ni, 0.30 to 0.80 percent of Cu, 0.10 to 0.40 percent of Mo, less than or equal to 0.05 percent of Al, less than or equal to 0.0010 percent of Ca, less than or equal to 0.003 percent of Ti, less than or equal to 0.0010 percent of O, less than or equal to 0.04 percent of As, less than or equal to 0.03 percent of Sn, less than or equal to 0.005 percent of Sb, less than or equal to 0.002 percent of Pb and the balance of Fe and inevitable impurities. The manufacturing process of the steel for the ball screw comprises the steps of electric furnace or converter, external refining, VD or RH vacuum degassing, continuous casting, continuous rolling, shearing or saw cutting, stack cooling, spheroidizing annealing, finishing and piece making and warehousing. Under the conditions of high yield strength (greater than or equal to 1380MPa) and tensile strength (greater than or equal to 1500MPa), the steel for the ball screw has low-temperature toughness (Charpy impact energy AKU2 at-40 DEG C is greater than or equal to 27J) far better than that of bearing steel.

Description

technical field [0001] The invention relates to the technical field of bar alloy steel, in particular to steel used in processing low-temperature-resistant high-strength ball screws and a manufacturing method thereof. Background technique [0002] In mechanical equipment, the ball screw is an indispensable transmission part for power and displacement transmission. According to the difference in the service environment, the ball screw used in some extreme environments must not only have the high precision and high wear resistance of the traditional screw , It also needs to meet the service requirements of maintaining high strength and toughness in harsh environments such as strong winds, huge waves, and severe cold in the polar regions of the earth. [0003] The traditional ball screw uses high-carbon chromium bearing steel, such as GCr15 grade, etc. After quenching and tempering, this kind of material can only meet the service requirements of the rigidity of contact with the...

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Problems solved by technology

[0003] The traditional ball screw uses high-carbon chromium bearing steel, such as GCr15 grade, etc. After quenching and tempering, this kind of material can only meet the service requirements of the contact rigidity with the steel ball, and the toughness in low temperature environment cannot meet the requirements of extreme environment. Service requirements, and because the heat treatment deformation of high-carbon bearing steel is difficult to control, the axial expansion and contraction properties of this type of material are the main factors that lead to the substandard grinding accuracy of the final ball screw

In addition, due to the high carbon content of this type of steel, the grinding performance after quenching is poor, and the incidence of processing quality problems such as grinding cracks is high.

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