汽轮机末级叶片用SP-700钛合金气体渗氮层结构和性能的研究  

Study on the Structure and Properties of the Gas-Nitrided Layer of SP-700 Titanium Alloy for the Last Stage Blade of Steam Turbine

作　　者：李聪[1] 聂冰悦 任延杰[1] 李微[1] 陈维 周立波 陈荐 LI Cong;NIE Bingyue;REN Yanjie;LI Wei;CHEN Wei;ZHOU Libo;CHEN Jian(School of Energy and Power Engineering,Changsha University of Science and Technology,Changsha 410114,China)

机构地区：[1]长沙理工大学能源与动力工程学院,长沙410114

出　　处：《动力工程学报》2024年第8期1153-1162,共10页Journal of Chinese Society of Power Engineering

基　　金：湖南省自然科学基金资助项目(2022JJ30597);国家自然科学基金资助项目(51775055)。

摘　　要：采用真空气体渗氮工艺在不同温度下对SP-700钛合金表面进行了渗氮强化。利用扫描电子显微镜、光学显微镜、显微维氏硬度仪、往复摩擦磨损试验仪、白光干涉三维表面轮廓仪和电化学工作站,分别测试了强化层的表面和截面形貌、硬度、耐磨性能和电化学腐蚀性能;通过浸泡腐蚀方法测定了涂层在HF溶液中的腐蚀行为。结果表明:渗氮温度对SP-700钛合金的微观形貌影响较大,随着温度的升高,试样表面氮化物数量增加,氮化物层更加致密;高温渗氮试样的硬度较基体提高了约1.9倍,相对耐磨性可达51.34;所有试样在3.5%NaCl溶液中均能自发钝化,有较好的耐电化学腐蚀性能;渗氮试样在HF腐蚀液中表现更优,渗氮温度越高,试样的耐腐蚀性能越好。Vacuum gas nitriding process was applied to strengthen the surface of the SP-700 titanium alloy at different temperatures.The surface morphology,cross-sectional morphology,hardness,abrasion resistance and electrochemical corrosion performance of the newly formed gas-nitrided layers were investigated using scanning electron microscope(SEM),optical microscope(OM),micro-Vickers hardness tester,reciprocating friction and warm damage tester,white light interference three-dimensional surface profiler and electrochemical workstation,respectively.The corrosion behavior of the gas-nitrided layers was determined by immersion corrosion method in HF solution.Results show that,the microstructural morphologies of the gas-nitrided layers are significantly influenced by the processing temperatures.With the increase of temperature,the amount of nitride increases and the nitride layer becomes denser.The hardness of the high-temperature gas-nitrided layer was about 1.9 times higher than that of the matrix,and the relative abrasion resistance can reach 51.34.All samples can be passivated spontaneously in 3.5%NaCl solution,indicating their good electrochemical corrosion resistance.The samples with gas-nitrided layer perform better in HF corrosion solution,and the higher the processing temperature,the better the corrosion resistance of the samples.

关 键 词：汽轮机 叶片 SP-700钛合金 气体渗氮 材料性能 

分 类 号：TK265[动力工程及工程热物理—动力机械及工程]