| Summary: | 碩士 === 國立雲林科技大學 === 環境與安全工程系碩士班 === 92 === The Cr-Mo series alloy steel possesses many advantages: such as good creep resistance, easy welding-ability and good corrosion resistance etc. Thus this type of steel is extensively used in power plants and petroleum of chemical industry for containment vessels, super-heater tube and steam pipes and in nuclear energy react for steam pipes. Components of steam pipes are chronically used at the temperature of about 600℃。 Therefore, creep fracture is the major ultimate failure mechanism during service. It may cause great property losses and influence on the power plant operating safety. Considerable research has been devoted to the assessment of creep-life by creep tests.
The low heat-resisting steel of the Cr-Mo alloy steel is extensively used in the boiler. This research is regarding 9Cr-1Mo alloy steel processed in the high-temperature creep tests under different temperature and stress condition. By discussing the property of the material and using Larson-Miller parameter and Ω method to assessment of the creep-life, in the research, I hope to establish basic high-temperature creep database.
The result shows that the temperature and stress have great influence on the creep-life of Cr-Mo. In order to maintain the long-term stability of the usage of 9Cr-1Mo alloy steel and reduce the damage of creep, the service condition of this material should be limited to 898 K and 30 MPa。
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