Carburized steel component excellent in low-cycle bending fatigue strength

A bending fatigue strength and carburizing steel technology, applied in the field of carburizing steel components, can solve the problem that the low cycle bending fatigue strength does not reach the level of low cycle bending fatigue strength, and achieve the effect of reducing CO2 emissions and improving fuel efficiency

Inactive Publication Date: 2012-05-23
NIPPON STEEL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0011] However, in all carburized steel parts, the low cycle bending fatigue strength does not reach the level of low cycle bending fatigue strength required today

Method used

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  • Carburized steel component excellent in low-cycle bending fatigue strength
  • Carburized steel component excellent in low-cycle bending fatigue strength
  • Carburized steel component excellent in low-cycle bending fatigue strength

Examples

Experimental program
Comparison scheme
Effect test

Embodiment

[0150] Next, examples of the present invention will be described, but the conditions in the examples are examples of conditions adopted for confirming the practicability and effects of the present invention, and the present invention is not limited to the examples of conditions.

[0151] In the present invention, various conditions can be adopted within the scope of achieving the object of the present invention without departing from the gist of the present invention.

[0152] (Example)

[0153] Steel materials having the composition shown in Table 1 and Table 2 were forged and stretched, and then soaked and normalized to produce rough-machined test pieces for low-cycle bending fatigue tests and rough-machined test pieces for wear tests.

[0154]

[0155]

[0156]The rough machining test pieces of Test No.1-21 (Invention Example), Test No.23-25 ​​(Comparative Example) and Test No.28-44 (Invention Example) were carried out for 930 hours in a reforming gas carburizing furn...

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Abstract

To provide a carburized steel component more excellent in low-cycle bending fatigue strength than heretofore. The carburized steel component contains a steel having a chemical composition comprising, by mass, 0.1-0.6% C, 0.01-1.5% Si, 0.3-2.0% Mn, <=0.02% P, 0.001-0.15% S, 0.001-0.03% N, 0.001-0.06% Al, <=0.005% O, and the balance Fe with inevitable impurities, and is subjected to carburizing, quenching and tempering treatments. The steel component has the surface hardness of HV550 to HV800, and the core hardness of HV400 to HV500.

Description

technical field [0001] The present invention relates to carburized steel parts having excellent low cycle bending fatigue strength. Background technique [0002] For gears such as components for mechanical structures, differential gears, transmission gears, and carburized shafts with gears, the roots of the teeth are sometimes fatigued due to low cycle fatigue (in the range of hundreds to thousands of cycles) Fatigue) and damage. In particular, for differential gears or transmission gears, it is desired to further improve the low-cycle fatigue strength. [0003] In the past, for the above-mentioned steel parts, surface carburized steel with a C content of about 0.2% such as JIS SCr420 and SCM420 was used as the steel material to ensure the toughness of the core, and the surface was formed by carburizing and quenching and low-temperature tempering at about 150°C. C is a tempered martensite structure of about 0.8%, thereby improving high-cycle bending fatigue strength and we...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C22C38/60C21D1/06C21D9/32F16H55/06
CPCF16H55/06C23C8/22C22C38/002C22C38/06C22C38/02C21D1/06C22C38/04C21D1/58C22C38/60C22C38/18C21D9/32
Inventor 小泽修司久保田学加田修西川元裕田中高志常阴典正
Owner NIPPON STEEL CORP
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