Abstract

We have developed a new steel strip for gaskets that can seal exhaust gas in 900°C environments. The concept for the material specified the seemingly conflicting requirements of high performance through the active use of γ’-Ni3 (Ti, Al) as a strengthening phase for high-temperature stability, together with a higher melting point for manufacturability. To enhance the relaxation properties, alloying elements that raised the amount and stability of strengthening phase γ’ and suppressed the precipitation of the harmful phase η-Ni3Ti were investigated using thermodynamic calculations, and 5.9 at% of Ti+Al and a ratio of 1.0 of Al/Ti were selected. In addition, to enhance hot rollability, the melting point was increased by reducing Nb and Cr contents as compared to Alloy 718. To maintain initial springiness and the stability of γ’ at high temperatures, the cold rolling reduction ratio was set at 30% to 40%. As a result, in heat load tests at 900°C, gaskets made of the developed alloy performed at the same level as Alloy 718 gaskets at 750°C.

References

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Author (organization or company)

• Hiroki YAMAMOTO（Material Research Center）
• Isamu SAITO（Honda Motor Co., Ltd.）
• Yoshiki KUMAGAI（Daido Steel Co., Ltd.）
• Yoshinori SUMI（Daido Steel Co., Ltd.）

Publication Information

Article of Honda R&D Technical Review Vol.37 (87 - 94)

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