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用Cr23A16Y0.203、Cr23A16CoZrTi、OCr25A15、Cr25A15Y0.013、Crl7A16Mo2、Cr13A16Mo2、Ni80Cr20、Fe-8Al-18Mn等合金的电热丝,在1000℃渗碳气氛中进行了寿命试验。电热合金丝通电加热并保持在1200℃或1350℃,测定它们断裂的时间。观察了这些合金的显微组织在寿命试验后发生的变化,并与在950℃液体渗碳200h后的变化相对照。在实验的基础上,讨论了电热合金与渗碳介质的交互作用。已经表明,Ni80Cr20及Fe-8Al-18Mn合金不宜长期暴露于渗碳气氛中使用,而加Y的Fe-Cr-Al合金己证明具有最好性能。含0.203wt%Y的Fe-Cr-Al合金良好的抗渗碳性能可以归因于合金在热处理或预氧化处理后在表面形成了保护性氧化皮,这种氧化皮是由α-Al_2O_3和Y_3Al_5O_2(YAG)相组成的。
The life test was carried out in a carburizing atmosphere at 1000 ℃ with the electric heating wire of Cr23A16Y0.203, Cr23A16CoZrTi, OCr25A15, Cr25A15Y0.013, Crl7A16Mo2, Cr13A16Mo2, Ni80Cr20, Fe-8Al-18Mn and other alloys. The electric alloy wires were heated by electric current and kept at 1,200 ° C or 1,350 ° C, and the time when they were broken was measured. The changes in the microstructure of these alloys after the life test were observed and compared with the changes after liquid carburizing at 950 ° C. for 200 h. Based on the experiment, the interaction between the electrothermal alloy and the carburizing medium is discussed. It has been shown that Ni80Cr20 and Fe-8Al-18Mn alloys should not be used for long-term exposure to carburizing atmospheres and Fe-Cr-Al alloys plus Y have proven to have the best properties. The good carburization resistance of the Fe-Cr-Al alloy containing 0.203 wt% Y can be attributed to the formation of a protective scale on the surface of the alloy after heat treatment or pre-oxidation, which is composed of α-Al 2 O 3 and Y 3 Al 5 O 2 (YAG) phase.