High-toughness narrow-hardenability gear steel with 20CrMnTiH, bar and manufacturing method of high-toughness narrow-hardenability gear steel

Abstract

The invention discloses high-toughness narrow-hardenability belt 20CrMnTiH gear steel. The gear steel further comprises the following chemical elements in percentage by mass besides Fe: 0.17%-0.20% of C, 0.17%-0.25% of Si, 0.8%-0.85% of Mn, 1%-1.1% of Cr, 0.02%-0.03% of Al, 0.04%-0.05% of Ti, 0.009%-0.014% of N, 0.01%-0.03% of V, less than or equal to 0.02% of Mo, less than or equal to 0.03% of Ni, less than or equal to 0.05% of Cu, less than or equal to 0.02% of Nb, less than or equal to 0.004% of Ca and less than or equal to 0.0003% of B. In addition, the invention further discloses a bar material prepared from the high-toughness narrow-hardenability belt 20CrMnTiH gear steel. The invention further discloses a preparation method of the high-toughness narrow-hardenability belt 20CrMnTiH gear steel. In addition, the invention also discloses a manufacturing method of the bar, which comprises the following steps: (1) smelting and casting; (2) heating; (3) forging or rolling; (4) quenching and tempering, wherein the austenitizing temperature of quenching is 840-1050 DEG C, and oil quenching is adopted after austenitizing; the tempering temperature is 180-220 DEG C, and air cooling or water cooling is carried out after tempering.

Description

technical field [0001] The invention relates to a steel material, a rod and a manufacturing method thereof, in particular to a 20CrMnTiH gear steel, a rod and a manufacturing method thereof. Background technique [0002] Gears are very important transmission parts in automobiles, engineering machinery and machinery manufacturing. During the operation of transmitting power and changing speed, there is both rolling and sliding between the meshing tooth surfaces of the gears, and the roots of the gear teeth are also subjected to alternating bending stress. [0003] In recent years, with the development of gear steel application fields towards high speed, heavy load, precision and low noise, the market requires gears not only to have good strength, toughness and wear resistance, but also to withstand impact, bending and contact stress well. It also needs to have excellent properties such as small heat treatment deformation and high dimensional accuracy. This puts forward highe...

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Problems solved by technology

[0006] However, at present, the hardenability requirements for the 2 / 3 band under 20CrMnTiH in my country's GB / T5216 are J5=36-44HRC, J9=30-38HRC, J15=22-31HRC, which is equivalent to a hardenability bandwidth exceeding 8HRC. The requirements for the hardenability bandwidth are stricter than the national standard, but only limited to the bandwidth ≤ 7HRC

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