Creep resistance of high-chromium steel and nickel-based alloy with oxidation-resistant coating for the components in advanced ultra supercritical steam generation

先进超超临界蒸汽发生部件抗氧化涂层高铬钢和镍基合金的抗蠕变性能

• 批准号: 460816-2013
• 负责人: Liu, Rong
• 金额: $ 2.19万
• 依托单位: Carleton University
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=618387
• 关键词: Creep; resistance; chromium; steel; nickel

The requirement of reducing the greenhouse CO2 emission has pushed the electrical power generation industry using the traditional fossil fuels to run steam turbines at temperatures above 700 degree C, which falls in the category of the so called advanced ultra supercritical (A-USC) steam turbines. To meet the high-temperature operating requirement of A-USC steam turbines (100,000 hours at 750oC), nickel-based alloy materials are to be used for parts that are directly in contact with the high temperature steam, including tubes, nozzle box (first stage nozzle), rotors and blades. Inconel 740 is one of the promising candidates. On the other hand, for economic reasons, parts that are not directly affected by the steam, for example, outer casings, are preferably made of traditional boiler materials, typically high chromium steel F91. For A-USC steam turbine components, the materials are all required to have high anti-creep strength and oxidation resistance at elevated temperatures. The existing materials, whether high Cr steels or Ni based superalloys, all exhibit deficiency in long-term creep performance because of the interference of oxidation. The available creep data for these materials were mostly obtained from short-term tests. The creep-oxidation interaction in these alloys has not been well understood as to predict their long-term behavior for application under the A USC condition. To solve these problems, the proposed research is aimed to further characterize the high-temperature creep resistance of Inconel 740 and F91; and in the meanwhile, to enhance the oxidation resistance of these substrates by applying a MCrAlY (where M represents Co, Ni or Co/Ni) coating on them; subsequently, to investigate the influence of the coating on the creep performance of these substrate materials. Since assurance by real material creep test may take a too long time for material design and characterization; a deformation mechanism based creep modeling approach will be utilized to depict the short-term creep behaviour and predict the long term creep resistance of these materials and their coating systems.

减少温室气体二氧化碳排放的要求推动了使用传统化石燃料的发电行业在700摄氏度以上的温度下运行汽轮机，这属于所谓的高级超超临界(A-USC)汽轮机的类别。为了满足A-USC汽轮机的高温运行要求(在750℃下运行100,000小时)，与高温蒸汽直接接触的部件将使用镍基合金材料，包括管子、喷嘴盒(第一级喷嘴)、转子和叶片。Inconel 740是很有希望的候选者之一。另一方面，出于经济原因，不直接受蒸汽影响的部件，例如外壳，最好用传统的锅炉材料制成，通常是高铬钢F91。对于A-USC汽轮机部件，材料都要求具有较高的抗蠕变强度和高温抗氧化性。现有的材料，无论是高铬钢还是镍基高温合金，由于氧化的干扰，都存在长期蠕变性能不足的问题。这些材料的蠕变数据大多是从短期试验中获得的。这些合金中的蠕变-氧化相互作用还不能很好地预测它们在AUSC条件下的长期应用行为。为了解决这些问题，本研究旨在进一步表征Inconel 740和F91的高温蠕变性能；同时，通过在这些基板上涂覆一层MCrAlY(其中M表示Co、Ni或Co/Ni)来提高它们的抗氧化性能；随后，研究涂层对这些基材蠕变性能的影响。由于实际材料的蠕变试验可能需要花费太长的时间来进行材料设计和表征，因此将采用基于变形机理的蠕变建模方法来描述这些材料及其涂层系统的短期蠕变行为并预测其长期蠕变抗力。