| Research on the overlaying property of FeaAl alloy with 18-8 stainless steel as base metal was conducted by the use of gas tungsten arc welding process, which mainly includes two aspects as follows:( I ) Processing property on overlaying: overlaying experiments were conducted under the conditions of variant welding parameters, examination and test on overlayer concerning its macromorphlogy, micromorphlogy , phase constitution and microhardness were also conducted. Results show that the primary problems in Fe3Al overlaying are:(l) a-Fe solid solution were detected in all overlayers with difference in amount;(2) liability to crack formation in fusion zone and arc pit is relatively great. In the end, optimal processing parameters in Fe3Al alloy overlaying under certain conditions were attained through comparative analysis.( II) Anti-oxidation property of overlayer in high temperatures: the anti-oxidation property of overlayer obtained in optimal welding parameters were conducted in the temperatures of 850C , 950C , 1050C , 11 50C ,mass-gain curves show that during the oxidation process, there is a change in oxidation mechanism. In temperatures of 850C , 950C, oxidation dynamic curves approximately follow parabolic law, whereas in the temperatures of 1050C , 1150C, they follow parabolic law periodically and cracking points appear on the oxidized film .It can be deduced from XRD patterns and SEM morphology of oxidation film that Cr can be the inductive element which brings about two different kinds of oxidation dynamic curves. The obstructing layer of diffusion is mainly composed of alpha alumina. Preferable and endurable oxidation property of overlayer can be achieved under the temperature of 1000C .
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