摘要
研究了3种不同Cr含量(质量分数)的奥氏体不锈钢在700℃下煤灰/高硫烟气环境中的腐蚀行为。结果表明,低Cr合金(19.13%)腐蚀最为严重,氧化膜由外层Fe_(2)O_(3)、内层Cr_(2)O_(3)及CrS组成,外层氧化膜剥落严重;中Cr合金(22.78%)氧化膜结构与低Cr合金类似,但腐蚀程度更轻;高Cr合金(24.00%)表面形成了稳定而致密的Cr_(2)O_(3)层,表现出比其他2种合金更好的抗高温腐蚀性。合金中的NbC会被氧化成Nb_(2)O_(5)分布在氧化膜中,Nb_(2)O_(5)的形成会破坏氧化膜的完整性,导致氧化膜更容易发生开裂。
With the rapid increase in thermal power generation units in China,the thermal power generation industry is facing pressures such as reducing costs,improving power generation efficiency and mitigating environmental problems.Thermal power generation units with a large capacity and high parameters result in high system efficiency,but they also amplify the corrosion failure problem of high-temperature components,especially the atmosphere/ash corrosion of outer tubes.Many studies regard-ing flue gas corrosion have shown that molten alkali metal sulfate can form on the surface of pipelines,causing severe corrosion damage,and the extent of corrosion is closely related to the sulfur content in raw coal.However,much attention has been paid to low-sulfur(standard coal combustion)environments in previous studies,with very few studies on high-sulfur environments.Austenitic stainless steels possessing a combination of excellent high temperature corrosion and fatigue resistances,are considered as promising construction materials for high temperature components in supercritical and ultra-supercritical fossil fuel power plants.Elements such as Cr and Nb have been shown to greatly affect the high temperature corrosion resistance of austenitic stainless steels;however few reports are available regarding the effect of Cr on corrosion resistance in high-sulfur flue gas environments and the effect of Nb on the corrosion resistance of Cr_(2)O_(3)-forming alloys.Therefore,in this study,the corrosion behavior of three types of austenitic stainless steels with different Cr contents was studied in a coal ash/high-sulfur flue gas environment at 700℃.Results showed that low Cr alloys formed a two-layered structure:an external Fe_(2)O_(3) layer and an internal layer with Cr_(2)O_(3) and CrS.Medium Cr alloys developed a similar structure oxide scale to low Cr concentration alloys,but the corrosion extent was modest.Conversely,a stable and dense Cr_(2)O_(3) layer was formed on the surface of the high Cr alloys,showing higher corrosion resistance than the other two alloys.The Nb in the alloys had some influence on the corrosion resistance of the alloys.The NbC in the alloys oxidized to Nb_(2)O_(5) and distributed in the oxide scale.The formation of Nb_(2)O_(5) destroyed the in-tegrity of the oxide scale and led to the easy cracking of the oxide scale.
作者
曹超
蒋成洋
鲁金涛
陈明辉
耿树江
王福会
CAO Chao;JIANG Chengyang;LU Jintao;CHEN Minghui;GENG Shujiang;WANG Fuhui(Shenyang National Laboratory for Materials Science,Northeastern University,Shenyang 110819,China;National Energy R&D Center of Clean and High-Efficiency Fossil-Fired Power Generation Technology,Xian Thermal Power Research Institute Co.,Ltd.,Xi'an 710032,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2022年第1期67-74,共8页
Acta Metallurgica Sinica
基金
国家重点研发计划项目Nos.2019YFF0217500和2016ZX05022-055
辽宁省优秀青年基金项目No.2019-YQ-03
中国华能集团有限公司科技项目No.HNKJ20-H43。
关键词
高温腐蚀
奥氏体不锈钢
煤灰/高硫烟气
硫化/氧化
high temperature corrosion
austenitic stainless steel
coal-ash/high sulfur flue-gas
sul-fidation/oxidation
作者简介
曹超,男,1994年生,硕士;通讯作者:蒋成洋,jiangchengyang@mail.neu.edu.cn,主要从事高温腐蚀的研究;通讯作者:鲁金涛,lujintao@tpri.com.cn,主要从事电站金属材料高温腐蚀与防护方面的研究。
