Study On The Molding Process Of The Fe-Si Intermetallics Compounds Inner-heating Casing To Improve Thermal Shock Resistance

In the hot-dip Zn-plating/Al -plating industry,the molten Zn/Al corroding equipment has been the most difficult problem in the industry.In recent years,hot-dip industry commonly uses the heating ceramic pot in order to reduce the molten Zn/Al corrosion the pot body.Today,the internal heat ceramic pot is spreading,Which has the great significance to exploiting and studying of the low-cost,high-quality,large-sized,long-life inside heater protection casing pipe.At present,inside heater protection casing pipe has not yet found the ideal material which not only has excellent quality of resisting molten zinc/aluminum corrosion but also has good high temperature mechanics property,So internal heating technology application and promotion are limited greatly.To solve this problem,the thesis use mechanical alloying -iron intermetallic compound powder of the vacuum annealing technology preparation to successfully produce Fe-Si intermetallic compound casing samples by different molding technology and check all kinds of molding technology casing samples by "water -track test approach" shock and molten resistance zinc/aluminum liquid corrosion and study composition and micro-morphology of a variety of molding casing samples by X-ray diffraction and scanning electron microscopy.Study results show that:Cold-pressure drying molding,forming pressure,C-2 binder content,lubrication method and drying process have a great impact on the thermal shock property.With the molding pressure increased,the strength of the casing increasing,shock resistance improving, If the glue content was too much,it will reduce the density of the casing pipe and the internal shock resistance lubricant.using semi-solid lubricant lubricating thermal shock is better the than the liquid lubricant.The sintering could effectively improve the density and intensity of the casing,which increases thermal shock resistance.significantly When samples were sintered using the cold-pressure sintering mold,the sintering temperature,holding time greatly impacted on thermal shock resistance of the casing.Within a certain scope,both improving the sintering temperature and extending the holding time could effectively improve the sintering quality of the casing,such as improving sintering strength,density,reducing porosity and pore diameter, thus also increased the thermal shock resistance of the casing.After 30 hours Molten-resistance Zn-Al corrosion,cold-pressing sintering sample and cold-drying sample do not appear the signs which was corrupted seriously,samples corroded are not found Al and Zn elements existence by X-ray diffraction analysis,Which illustrate that protection casing of Fe-Si intermetallic compounds have good corrosion resistance using the two molding processes.After graphite fiber and Fe-Si intermetallic compounds were blend physically in accordance with a certain volume ratio,Using cold-pressure and thermal shock resistance of the casing,Which maybe related to interface of the fiber and Fe-Si intermetallic compounds linking badly or maybe ours process methods are inappropriate.So,These need us to improve them after subject studying.In short,the thermal shock resistance was directly related to the internal quality of the casing,using different approaches,maximumly improving the quality of the internal casing, reducing the internal defects and improving strength could effectively increase the thermal shock resistance and corrosion resistance of the Fe-Si intermetallic compounds.