1. Home
  2. Honda R&D Technical Review Vol.23 N...
  3. Development of Nitrocarburized High...

Technical Review e-Book: Summary

Development of Nitrocarburized High-strength Crankshaft with No Rare Metals Added

Article of Honda R&D Technical Review Vol.23 No.2


Conventional nitrocarburized high-strength crankshafts secure high fatigue strength through a strengthening mechanism using the rare metal molybdenum (Mo). In contrast, a crankshaft with high fatigue strength equal to that of the conventional material was developed without the addition of rare metals by using copper (Cu) and chromium (Cr) and optimizing the material design.
Cr increases the hardness near the surface layers during nitrocarburization, which effectively increases the strength. However, in this case cracking easily occurs when plastic deformation is applied to straighten crankshaft bending that occurs in the nitrocarburization process, which has made it a challenge to actively use Cr. The developed material combines hardening by Cr with ferrite solid solution strengthening by Cu, and enhances straightenability by suppressing the Cr content required for strengthening. This simultaneously achieved both high fatigue strength and good straightenability without the addition of rare metals.


(1) Iwama, N.: Trend of Special Steel for Automotive Parts, JSAE, Vol. 55, No. 10, p. 64-68 (2001)
(2) Suzuki, N., Tani, K.: Recent Trend of Nitrided Products, Journal of the Japan Society for Heat Treatment, Vol. 32, No. 5, p. 262-266 (1992)
(3) Mori, M., Koumoto, T., Harikago, T., Owaki, S., Iwama, N.: Development of High Fatigue Strength Microalloyed Steel Crankshaft, JSAE Technical Paper, No. 47-00, p. 9-12 (2000)
(4) Onda, H., Asai, T., Fujiki, K., Kudo, H., Murofushi, K.: Development of High-strength Induction Hardened Crankshaft, Honda R&D Technical Review, Vol. 15, No. 2, p. 175-182
(5) Nagasaka, H., Mori, H., Araki, S., Ishibashi, Y., Hamada, T., Takami, M.: Fatigue Strength Improvement of Solid Type Crankshaft through Fillet Cold Rolling, Kobe Steel Engineering Reports, Vol. 48, No. 1, p. 68-71 (1998)
(6) Asai, T., Takitani, Y., Sano, N., Matsumoto, H.: Development of Non-normalized Nitrocarburized High Strength Crankshaft, Honda R&D Technical Review, Vol. 19, No. 1, p. 89-96
(7) Watanabe, Y.: Reserves and Production of Rare Metals and Prediction of Their Future Demands and Supplies, Journal of Society of Automotive Engineers of Japan, Vol. 63, No. 11, p. 14-18 (2009)
(8) Matsumura, Y., Kurebayashi, Y., Konagaya, D., Mizuno, K.: Development of Nitrocarburizing Steel for Crankshafts, SAE Technical Papers, 1999-01-0601 (1999)
(9) Hobo, M., Takada, K.: Effect of Small Amounts of Cu on Nitrocarburizing Characteristics for Medium-Carbon Steels, DENKI-SEIKO, Vol. 77, No. 1, p. 29-38 (2006)
(10) Inoue, K., Matsumura, Y.: Influence of Alloying Elements on Hardness Distribution after Nitrocarburizing in Medium Carbon Steel, DENKI-SEIKO, Vol. 75, No. 1, p. 11-18 (2004)
(11) Inoue, K., Nakamura, S.: Influence of C and V Contents on Mechanical Properties of Microalloyed Ferrite-Pearlite Steels, DENKI-SEIKO, Vol. 65, No. 1, p. 22-30 (1994)

Author (organization or company)

Yoshihiro TAKITANI(Automobile R&D Center)、Isamu SAITO(Automobile R&D Center)、Takahiro MIYAZAKI(Daido Steel Co., Ltd.)、Keiichiro KAMIYA(Daido Steel Co., Ltd.)

We would like to get your opinion on this research paper. (This is only applicable to registered members.)

The readers of this research paper have also selected these research papers.

Visualization of Oil Behavior when Piston Pin Noise Occurs
Article of Honda R&D Technical Review Vol.23 No.2
Effects of Low-viscosity Engine Oil on Fuel Economy and Wear
Article of Honda R&D Technical Review Vol.22 No.2
Proposal of New Bearing Simulation Rig Tester for High Efficiency Engine Bearing Development
Article of Honda R&D Technical Review Vol.18 No.2