【摘要】 采用1Cr18Ni9Ti不锈钢、YG8硬质合金和Al2O3/(W,Ti)C陶瓷3种材料制备了水煤浆喷嘴,考察了其在水煤浆雾化和燃烧过程中的热冲蚀磨损机理.结果表明:喷嘴材料的硬度对水煤浆喷嘴的热冲蚀磨损行为具有重要影响;在相同条件下,高硬度的Al2O3/(W,Ti)C陶瓷喷嘴的冲蚀率最低,YG8硬质合金次之,硬度较低的1Cr18Ni9Ti不锈钢喷嘴的冲蚀率最高;在热冲蚀磨损工况下,1Cr18Ni9Ti不锈钢水煤浆喷嘴主要呈现微切削特征,YG8硬质合金水煤浆喷嘴主要呈现晶粒剥落特征,而Al2O3/(W,Ti)C陶瓷水煤浆喷嘴主要呈现研磨损伤和热崩特征.更多还原

【Abstract】 Al2O3/(W,Ti)C ceramic composite was prepared by hot pressing technique. Then the nozzles used in the coal water slurry burning were made from the resulting ceramic composite and 1Cr18Ni9Ti stainless steel and YG8 cemented carbide. The erosion behaviors of the nozzles in the coal water slurry buring were evaluated on a DNS21.0SM steam boiler, at a coal water slurry comsumption rate of 200 kg/h and concentration of (65±2)%, a slurryfeeding pressure of 0.2 MPa, pulverized gas pressure of 0.35～0.4 MPa, and maximum temperature of 1 300 ℃. The eroded bore surface morphologies of the nozzles were observed with a scanning electron microscope. Results showed that the hardness of the nozzles played an important role in determining the erosionresistance in the coal water slurry (CWS) burning. The Al2O3/(W,Ti)C nozzles with high hardness exhibited lower erosion rates, while the 1Cr18Ni9Ti stainless steel nozzles with low hardness showed higher erosion rates under the same test conditions. The nozzle made from 1Cr18Ni9Ti stainless steel was dominated by plowing and microcutting, that made from YG8 cemented carbide was characterized by grain peeling off, and the one made from the Al2O3/(W,Ti)C ceramic composite was dominated by thermal shock and grinding.更多还原