| With the rapid development of transportation, aerospace, construction and other industries, the application of aluminum products is becoming more and more widely. The quantity demanded of electrothermal alloy which plays the role as heater producer in the melting furnace, holding furnace for manufacturering aluminum alloy increases. However, the service condition of the electrothermal alloy whose lifetime is no more than1year is rigorous and the average lifetime is only three months. This is a serious problem for the sustainable development of resources. It is the highest priority to find out the factors which affected the service lifetime of electricthermal alloy and develop a product with long lifetime.This paper begins with preliminary work to find the factors which affect the life of electricthermal alloy. Five materials of Cr20Ni80,0Cr25Al5,0Cr21Al6Nb,0Cr27Al7Mo2and HRE were selected for pre-oxidation treatment and then installed in the aluminum furnace, after which the lifetime of the materials is compared. Then the Kanthal AF-1was added into the form alloys to analyze the metallography and impurity with metallographic microscope and ImageJ software. It showed that the grain size of0Cr21Al6Nb is the smallest and the0Cr25Al5possessed the biggest grain size. Besides, the quantity of impurities in Kanthal AF-1is the least and the most in the0Cr25Al5.The atmosphere in the furnace of Aluminum furnace was analyzed. It is found that the hydrogen has a certain influence on the service lifetime of electricthermal alloy strip. The service environment of the electricthermal alloy strip was simulated and the KQ-3S metal diffusible hydrogen analyzer was employed to test the diffusible hydrogen. The result showed that the diffusible hydrogen was dissolved in the electricthermal alloy strip under high temperature, which mean that hydrogen had some effect on electricthermal alloy.The oxidation resistance of the electricthermal alloy which is an important indicator for the lifetime was kinetic analyzed. The micro structure and stress principal of the oxidation film was also analyzed. The results indicated that rare earth could improve the oxidation resistance of the electricthermal alloy. The stress of the oxidation film was caused by growth stress and thermal stress caused by temperature changes. The stress can be mainly released by high-temperature creep, cracking and spalling of the oxide film.The ABAQUS thermoelectric coupling module was employed to analyze the temperature distribution of electrothermal alloy strip. The stress was analyzed by sequential coupled thermal stress analysis module. The bending place of electrothermal alloy strip where the maximal temperature and stress occurred maybe the place where to broke.The result from the actual circumstances of the breakage of the electrothermal alloy strip showed that it was the same to the result of thermoelectric coupling analysis and thermal stress analysis, which indicated that the simulation analysis was correctFrom the above, The factors which influence the lifetime of electrothermal alloy strip has been found and analyzed, Which made a contribution to develop the development of electrothermal alloy strip with50%lifetime improvement. |
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