| 摘要 |
PROBLEM TO BE SOLVED: To provide an austenitic heat-resistant cast steel in which thermal fatigue characteristics can be improved by alleviating thermal expansion while maintaining tensile strength at high temperature.SOLUTION: The austenitic heat-resistant cast steel contains C:0.1 to 0.6 mass%, Si:1.0 to 3.0 mass%, Mn:0.5 to 1.5 mass%, P:0.05 mass% or less, S:0.05 to 0.3 mass%, Ni:9 to 16 mass%, Cr:14 to 20 mass%, N:0.1 to 0.2 mass% and the balance iron with inevitable impurities. In the austenitic heat-resistant cast steel, a matrix structure is configured of austenite crystal grains and a ferrite phase is dispersed and interposed between the austenite crystal grains so as to cover the austenite crystal grains. An area ratio of the ferrite phase is in the range of 1 to 10% based on the whole structure of the austenitic heat-resistant cast steel. The austenitic steel further contains Cu of 1.0 to 3.0 mass%. |
