| The phosphoric-chemical industry is important and basic for the national economy. Its products such as phosphoric acid, various phosphate and phosphate fertilizer, which are the indispensable and basic material for many industries, are widely used. But the interaction between corrosion and wearing, which leads to the short service life of the equipment in the phosphorous producing process, seriously restricts the smooth development of phosphoric-chemical. Therefore, the developing and final applying of new corrosion-abrasion resistant material according to the characteristics of this industry, is highly concerned by the material researchers.High chromium ferrite stainless steel manifests the great corrosion-abrasion resistance, what's more, because its composition includes low nickel or no nickel, the development and application meets the demand of our national condition. However, this material is very brittleness, and easy to embrittle and crack sometimes. As a result, its production and application are restricted. This thesis describes a new ferrite stainless steel, which improve its performance obviously through microalloy technology and optimization method.Considering the requirements of the equipment material, startingwith the efficacy losing analysis of phosphoric acid slurry pump, we carried out the design of composition and processing technology of ferrite stainless steel, and then prepared the sample. By means of metallograph, electronic probe, mechanical properties experiences and corrosion wear test, we analyzed the microstructure and properties of steel.Because of the lacking research on the principle of microalloy in the stainless steel, such principle is discussed in this thesis, and the method of theoretical calculation is described, too.Meanwhile, according to researching accomplishments in laboratory, we analyzed some technologies under industrializing produce condition, such as smelting, foundry and heat treatment for this new material. With these technologies, the ductility of the new stainless steel has been improved obviously, and its casting product rate has been increased notably.Finally, analysis of the market, the social and economic benefits of the new ferrite stainless steel have been carried out. Basing on these, we carried through the researches on the application, and recommend this new stainless steel to the society. |
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