Flying-shear main-transmission gearwheel steel and preparation method thereof

Abstract

The invention discloses a flying-shear main-transmission gearwheel steel and a preparation method thereof. The flying-shear main-transmission gearwheel steel comprises the following elements in percentage by mass: 0.10-0.20% of C, 2.00-3.00% of Cr, 2.50-3.50% of Ni, 0.4-1.00% of Mo, 0.10-0.40% of Si, 0.40-1.00% of Mn, at most 0.25% of Cu, at most 0.1% of Al, at most 0.020% of P, at most 0.015% ofS, at most 30ppm of O, at most 100ppm of N and at most 2ppm of H. The preparation method comprises the following steps: (1) smelting according to the percentage by mass to obtain a forging stock; (2)forging; (3) carrying out normalizing heat treatment; (4) carrying out gear hobbing; (5) carrying out surface carburization quenching heat treatment; and (6) carrying out gear grinding. The inventionenhances the bearing capacity and reliability of the gearwheel, and satisfies the production demands of high-carbon high-alloy steel and enhanced specifications, thereby having wide popularization and application prospects.

Description

technical field [0001] The invention belongs to the rolling machinery technology in the area of ​​bar steel and hot rolling, and relates to a gear manufacturing process, in particular to a flying shear main transmission large gear steel and a manufacturing method thereof. Background technique [0002] In areas such as bar steel and hot rolling, flying shears are important equipment for cutting the head, tail or segments of steel billets. The main transmission mechanism of flying shears is a key component for transmitting torque, realizing shear blade movement and shearing functions. The large gear is the core of the main transmission mechanism of the flying shear. In addition to meeting the requirements of heavy load, impact resistance, wear resistance, contact fatigue resistance and bending fatigue resistance, it also has strict requirements on the precision and stability of the transmission. [0003] At present, the start-stop four-link crank flying shear transmission mech...

AI Technical Summary

Problems solved by technology

[0007] (1) There are welding residual stress and stress concentration in the welding part of the web, which may easily cause the web to crack

[0008] (2) The ring gear is a large-diameter thin-walled annular workpiece, which is prone to deformation during processing and affects the machining accuracy of the tooth shape

[0009] (3) Due to the limitations of the induction hardening process, it is difficult to ensure the uniformity of the hardened layer on the tooth surface of the large gear treated by induction hardening, which affects the contact fatigue performance of the tooth surface

[0010] (4) The large gear is welded together by hubs, spoke plates and ring gears of different steels. During overall carburizing and quenching, cracks in welds and other parts and gear distortion are likely to occur. Carburizing and quenching is carried out before tailor welding and grinding Tooth, tailor welding deformation and then grinding teeth will cause uneven carburized layer on the tooth surface, and post-welding stress relief annealing treatment will easily damage the carburized layer structure

This technology is not suitable for large gears with heavy loads and shock conditions

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