Abstract

In conventional high-strength gear steel, the addition of Ni and Mo reduces the non-martensitic structure at the process of quenching the gear surface after carburizing. This makes the gear surface martensitic and thereby guarantees high fatigue strength. However, Ni and Mo are rare metals, and it has become impossible to ignore the increase in material costs caused by the addition of large quantities of these metals. Based on the mechanism by which non-martensitic structures form the mechanism by which non-martensitic structures form, we have developed a method for producing carburized high-strength steel in which the application of cold-oil to the quenching process improves the cooling speed and the chemical composition of the steel is optimized. Using no Ni and reducing Mo to less than half, we have developed a new gear steel with a greater level of fatigue strength than conventional steel. In other words, it was made possible to reduce the amount of rare metals used while simultaneously achieving high fatigue strength.

References

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Author (organization or company)

• Akihito NINOMIYA（Automobile R&D Center）
• Yoshinari OKADA（Automobile R&D Center）
• Masayuki HORIMOTO（NIPPON STEEL & SUMITOMO METAL CORPORATION）
• Syusaku MAEDA（NIPPON GREASE Co. ,Ltd.）

Publication Information

Article of Honda R&D Technical Review Vol.26 No.1 (125 - 130)

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