Grain-refined gear steel and production process thereof

A technology of grain refinement and production process, applied in the field of metallurgy, can solve the problems of affecting the fatigue life of gears, affecting the machining accuracy, serious harm, etc.

Active Publication Date: 2012-10-03
ZENITH STEEL GROUP CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Its steel matrix structure is pearlite + ferrite structure. Since 20CrMnTi steel contains Ti in its composition, it is inevitable to produce clusters of large or small TiN inclusions inside the steel. Ti is an important element in gear steel, but Ti TiN with large particles and sharp edges is easy to form in steel, which is the source of fatigue cracks, and its damage is more serious than oxide inclusions
The main reason is that the TiN non-deformable inclusions are harder than the matrix, which affects the machining accuracy, and will become a source of fatigue during use and affect the fatigue life of the gear

Method used

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  • Grain-refined gear steel and production process thereof
  • Grain-refined gear steel and production process thereof
  • Grain-refined gear steel and production process thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0052] Embodiment 1 of the present invention, reference example 220CrMnTi

[0053] 1) chemical composition is as follows table 1 (wt%):

[0054] project C Cr mn Si P S Alt B Ni Mo Cu N Ti Example 1 20CrMnBAlN 0.19 0.85 0.85 0.26 0.015 0.025 0.0500 0-0018 0.01 0.005 0.04 0.0120 Reference example 2 20CrMnTi 0.19 1.06 0.95 0.24 0.012 0.007 0.0350 0.01 0.005 0.04 0.056

[0055] 2) The mechanical properties are compared in the following table 2:

[0056] Table 2

[0057]

[0058] 4) Grain degree: 20CrMnAlS grade 8, 20CrMnTi grade 7.

[0059] 5) Microstructure: The hot-rolled state is F+P microstructure.

[0060] 6) Low magnification as shown in Table 3:

[0061] table 3

[0062]

[0063] 7). Inclusions are as shown in Table 4:

[0064] Table 4

[0065]

[0066] 8) Comparison of terminal hardenability (20CrMnAlS and 20CrMnTi) is shown in Table 5:

[0067] table 5

[0068]

[...

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Abstract

The invention discloses grain-refined gear steel and a production process of the grain-refined gear steel. The gear steel comprises the following compositions in percentage by weight: 0.14-0.22% of C, 0.20-0.35% of Si, 0.80-1.15% of Mn, 0.80-1.25% of Cr, 0.030-0.060% of Al, less than or equal to 0.035% of P, 0.015-0.030% of S, 0.0005-0.030% of B, less than or equal to 0.080% and more than or equal to 0.0140% of N, less than or equal to 0.30% of Ni, less than or equal to 0.30% of Mo, less than or equal to 0.20% of Cu, and the balance of Fe and inevitable impurities. The production process comprises the procedures of smelting, continuous casting and rolling. According to the invention, the refined grains of intracrystalline ferrite are fully used, so that the impact strength is improved, and the fatigue characteristic is improved.

Description

technical field [0001] The invention belongs to the field of metallurgy, and relates to a gear steel with fine grains and a production process thereof. Background technique [0002] 20CrMnTi steel accounts for about 50% of China's automotive gear steel manufacturing. Its steel matrix structure is pearlite + ferrite structure. Since 20CrMnTi steel contains Ti in its composition, it is inevitable to produce clusters of large or small TiN inclusions inside the steel. Ti is an important element in gear steel, but Ti TiN with large particles and sharp edges is easy to form in steel, which is the source of fatigue cracks, and its damage is more serious than oxide inclusions. The main reason is that the TiN non-deformable inclusions are harder than the matrix, which affects the machining accuracy, and will become a source of fatigue during use and affect the fatigue life of the gear. [0003] Therefore, there are mainly two measures to reduce the chance of TiN formation. One is ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/54C22C38/44
Inventor 王时林
Owner ZENITH STEEL GROUP CORP
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