Effect of Nb on high-temperature properties for ferritic stainless steel
- Nippon Steel Corp., Futtsu (Japan). Steel Research Labs.
- Nippon Steel Corp., Hikari (Japan). Hikari Works
- Nippon Steel Corp., Kitakyushu (Japan). Yawata Works
- Nippon Steel Techno Research Corp., Kawasaki (Japan)
- Nippon Steel Corp., Tokai (Japan). Nagoya Works
In order to improve the efficiency of automobile engines and to reduce their weight, there is a move toward the use of conventional stainless steel sheets and pipes for exhaust manifolds to replace cast iron, the traditional material for this application. The exhaust manifold is used in an environment that includes engine vibrations as well as heating and cooling cycles caused by the travel pattern. Therefore, among high-temperature characteristics, thermal fatigue resistance is an important one that affects the life span of an exhaust manifold. Generally, austenitic steels have higher strength at high temperature than ferritic steels. However, type 304, a typical austenitic stainless steel, has less thermal fatigue resistance than type 430, a typical ferritic stainless steel. This is because austenitic steels have higher coefficient of thermal expansion than ferritic steels. Therefore, to obtain a material with excellent thermal fatigue resistance, it would conceivably be best to attempt to increase the high temperature strength of ferritic stainless steels. The present study centered on improvement of the high-temperature proof strength of ferritic stainless steels. The mechanism of high temperature strengthening by Nb addition, which was shown to be one of the most effective methods to improve proof strength at high temperature, was discussed.
- OSTI ID:
- 382540
- Journal Information:
- Scripta Materialia, Vol. 35, Issue 6; Other Information: PBD: 15 Sep 1996
- Country of Publication:
- United States
- Language:
- English
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