Steel for ball screw bearing and manufacturing method thereof

Abstract

The invention relates to steel for a ball screw bearing. Alloy components of the steel comprise, by mass, 0.45-0.60% of C, 0.15-0.40% of Si, 0.50-0.80% of Mn, 0.15-0.40% of Cr, 0.002-0.006% of B, 0.02-0.07% of V, less than or equal to 0.015% of S, less than or equal to 0.025% of P, less than or equal to 0.10% of Mo, less than or equal to 0.08% of Al, less than or equal to 0.0010% of Ca, less thanor equal to 0.0010% of O, less than or equal to 0.04% of As, less than or equal to 0.03% of Sn, less than or equal to 0.005% of Sb, less than or equal to 0.002% of Pb, and the balance Fe and inevitable impurities. A preparation process of a bar product comprises the steps of molten steel smelting, continuous casting, cogging-down, hot rolling, tempering, stress relief annealing and the like. The final properties meet the conditions that the surface hardness of the bar reaches 220-260 HBW, the metallographic structure of the bar is a uniform sorbite structure, the austenitic grain size of the bar is higher than or equal to the seven-level, the yield strength of the bar is 600-800 MPa, the tensile strength of the bar is 800-900 MPa, and the percentage elongation of the bar is greater than orequal to 15%.

Description

technical field [0001] The present invention relates to the manufacture of bearing steels in iron-based alloys. Background technique [0002] The ball screw pair is one of the commonly used transmission devices in transmission machinery that uses the rolling of balls between the screw and the nut to simultaneously realize the functions of power transmission and motion conversion. It has the characteristics of high precision, high efficiency and reversibility at the same time. It has become the key executive component in the driving process of various CNC machine tools, automated machinery and machining centers. It is widely used in automobiles, machinery, nuclear industry, aviation, aerospace, etc. field. The rolling screw pair is usually composed of four parts: the screw bearing, the ball, the nut and the ball circulation return device. [0003] The ball screw bearing is the key component of the ball screw pair. The surface hardness and wear resistance of the ball screw b...

AI Technical Summary

Problems solved by technology

[0006] At present, the medium-carbon ball screw bearing steel used at home and abroad is mainly 50CrMo, which has high alloy element content and belongs to ultra-high-strength alloy-bonded structural steel. After quenching and tempering, the strength and toughness are high, but due to the high alloy content, the cost is high. , In addition, due to the high alloy content and high hardenability of the steel, it is easy to produce bainite structure after quenching and tempering, and subsequent heat treatment is easy to cause deformation

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