| The development of ferritic stainless steel CrSOMo used in phosphoric production equipments has been introduced in this paper. The chemical composition, smelting, foundry and heat treatment processes of CrSOMo have been designed. By means of microscope. X-ray diffraction spectrum, EMPA methods and several tests including mechanical properties, electrochemistry, corrosion wear, on-site plate hanging, the microstructure of steel has been observed and analyzed, performance has been studied, and corrosion-abrasion, fragility mechanism, and microalloy application in ferritic stainless steel have been explored comprehensively.The test results of electrochemistry, corrosion wear and on-site plate hanging have been analyzed. The analytical result shows that CrSOMo has enough corrosion resistance in phosphoric acid slurry because it has high chromium and low carbon. Due to precipitation of high hardness carbides such as (Cr, Fe^aCe- (Cr, Fe)7C3. Mo2C. the hardness and wear resistance of Cr30Mo have been increased. So Cr30Mo has good corrosion-abrasion resistance in phosphoric acid slurry.Based on the analyses of microstructure, mechanical properties, corrosion-abrasion resistances and fracture of cast ferritic stainless steel Cr30Mo with various carbon content, it can be affirmed that high carbon is advantage to increase steel hardness, but disadvantage to suppress brittleness and increase corrosion-abrasion resistance. With carbon content increasing, the carbide network on the fertile grain boundary sprouting and propagating. The fracture mode has been changed from cleavage to along boundary and the intergranular corrosion induced by solution chromium decreasing.The effects of alloy elements Nb, V, Ti, RE on mechanical properties, corrosion-abrasion resistance, fragility of ferritic stainless steel Cr30Mo have been investigated. The results show microalloy is beneficial to increas corrosion-abrasion resistance and suppress brittleness of Cr30Mo. Theboundary of ferrite has been clarified and fined by adding RE into CrSOMo. The intergranular corrosion induced by solution chromium decreasing can be restrained for Nb, V, Ti combing carbon in the steel . The wear resistance of stainless steel can be increased for the precipitation of microalloyed carbides. The size of microalloyed carbides is very small and some is only 2~3nm. So microcrack extending can be restrained.The foundry and heat treatment processes have been explored in order to improve properties of stainless steel. The method of solution heat treatment at high temperature with cooling controlled has been put forward.
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