深度调峰长期服役TP347H钢管内壁氧化皮结构与形成机理  

Microstructure and Formation Mechanism of Inner-wall Oxide Layers of TP347H Steel Tube in Long-term Service Involving Deep Peak-load Shaving

作　　者：王波 张健 杨平 王若民 胡玉璋 汤文明[1] WANG Bo;ZHANG Jian;YANG Ping;WANG Ruo-min;HU Yu-zhang;TANG Wen-ming(School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China;Anhui Xinli Electric Technology Consulting Co.Ltd.,Hefei 230601,China;Department of Technology,Wenergy Hefei Power Generation Co.Ltd.,Hefei 230041,China)

机构地区：[1]合肥工业大学材料学与工程学院,合肥230009 [2]安徽新力电业科技咨询有限责任公司,合肥230601 [3]皖能合肥发电有限公司技术部,合肥230041

出　　处：《装备环境工程》2023年第6期117-125,共9页Equipment Environmental Engineering

基　　金：安徽新力电业科技咨询有限责任公司科技项目(2020咨-KJ-02)。

摘　　要：目的掌握和应对深度调峰带来的新的安全隐患,对某深度调峰超临界机组的高温过热器和屏式过热器TP347H钢管内壁氧化皮开展研究。方法采用物相成分测试和显微组织分析相结合的方法,探讨氧化皮的结构及其形成机理。结果中间气孔层将氧化皮分为内外2层,外层为Fe_(2)O_(3),结构疏松;内层较致密,主要为(Fe,Ni)Cr2O4,其中部分晶界富Cr相与含氧水蒸气反应、气化,形成气孔。含氧水蒸气通过气孔向钢基体扩散,并与其中的Cr反应,形成不连续的Cr_(2)O_(3)薄层。钢中的Fe原子通过Cr_(2)O_(3)薄层的缝隙扩散至内外层氧化皮界面,氧化形成Fe_(2)O_(3),促进外层氧化皮的生长。结论深度调峰促进了管道内壁氧化及氧化皮中气孔的形成,同时在外层氧化皮表层诱发微裂纹,促使氧化皮剥落。The work aims to study the inner-wall oxide layers of the TP347H high-temperature superheater and pendant su-perheater tubes of a super critical unit involving deep peak-load shaving to master and handle the new safety issues brought with deep peak-load shaving.Phase composition and microstructure tests were conducted to clarify microstructure and its formation mechanism of the oxide layers.The results showed that the oxide layer was divided into the inner and outer sub-layers by the medium layer of pores.The outer-sublayer had a loose structure,and consisted of Fe_(2)O_(3);meanwhile,the inner-sublayer was dense,and mainly consisted of(Fe,Ni)Cr2O4,in which the Cr-rich grain-boundary phase partly reacted with the vapor contain-ing oxygen,and then gasified to form the in-situ pores.The vapor diffused through the pores,and reacted with Cr in the steel,resulting in formation of the thin discontinuous Cr_(2)O_(3) layer.On the other hand,the Fe atoms in the steel diffused into the in-ner/outer sublayer interface though the voids in the thin Cr_(2)O_(3) layer,and reacted with the vapor to form Fe_(2)O_(3),promoting the growth of the outer sublayer.Deep peak-load shaving accelerates oxidation of the inner-wall of the TP347H steel tubes and for-mation of the pores in the oxide layers,and also induces microcracks in the outer sublayer.As a result,exfoliation of the in-ner-wall oxide layer is promoted.

关 键 词：深度调峰 TP347H钢管 氧化皮 显微结构 形成机理 

分 类 号：TG172.8[金属学及工艺—金属表面处理]