| Supermartensitic stainless steel is a new kind of stainless steel by improving theconventional martensitic stainless steel with decreasing carbon content, adjusting thecontents of alloying elements, improving technic of processing and heat treatment.Compare with Traditional martensitic stainless steel, it has good plastic and toughness,excellent corrosion resistance, good welding performance, and maintain the highstrength and hardness. At present, the study of super martensitic stainless steel isconcentrated on chemical composition, mechanical properties, heat treatment andcorrosion resistant properties, etc. However, former works have rarely reported theerosion-corrosion behavior of supermartensitic stainless steel, which perform greaterosion resistance attributed to the high strength inherited from martensitic stainlesssteel and improved corrosion resistance. Hydrometallurgy process has a large amountof solid particle particle in the slurry medium, thin-H2SO4and a large amount ofimpurity particles, the slurry pump failure due to erosion-corrosion. Therefore, it isgreat importance to investigate on the erosion-corrosion behavior of supermartensiticstainless steel under the condition of acid liquid-solid two phase flow. In this paper,the behavior of erosion-corrosion of materials was testing by using a self-madeerosion-corrosion device. Some main factors of erosion-corrosion process such astemperature, sand content, pH valuo, flow rate affecting the supermatensiticstainlessssteel and contrast material2Cr13was study by mass loss method. Acomparative studies of erosion corrosion behavior of supermartensitic stainless steelsS-165under different heat treatments,2Cr13and316L were carried out in theliquid-solid two phases flow environments and the corrosion behaviors were also studied by using electrochemical method. The effects of low temperature plasmanitriding on corrosion and erosion-corrosion resistance of S-135and2Cr13stainlesssteel were also investigated. The corrosion surface topographic was observed byoptical microscopy and scanning electron microscopy, and the erosion-corrosionmechanism was analyzed in conclusion. The main research conclusion is:(1) The erosion-corrosion rate increased with increasing temperature and erosionspeed, reducing pH.In a certain range, erssion-corrosion rate increase with sandcontent, there exist a “critical sand content”, when the sand content higher than the“critical sand content”, the erosion-corrosion rate decreased.(2) The anti-erosion-corrosion performance of supermartensitic stainless steelunder selected heat treatment were better than that of316L and2Cr13stainless steels.It was founded that the sample which was achieved by quenching S-165at960℃andtempering at630℃showed the best erosion corrosion resistance, and its corrosion ratewas reduced by62.5%,25%and50%than that of S-165samples quenched at1000℃and tempered at630℃, quenched at1050℃and tempered at630℃, as well asquenched at1000℃and tempered at525℃, respectively.(3) Low temperature plasma nitriding enhance the corrosion resistance andhardness of2Cr13, the anti-erosion-corrosion performance was also improve. Lowtemperature plasma nitriding enhance the hardness and of S-165, however, thecorrosion resistance was decreasing, the anti-erosion-corrosion performance was alsodecreasing. |
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