王锐坤,周晴雯,高岩.高碳奥氏体耐热钢晶间腐蚀行为与纳米化快速脱敏的研究进展[J].表面技术,2022,51(3):1-11, 50.
WANG Rui-kun,ZHOU Qing-wen,GAO Yan.Research Progress on Intergranular Corrosion Behavior and Rapid Desensitization by Surface Nanocrystallization of High-carbon Austenitic Heat-resistant Steel[J].Surface Technology,2022,51(3):1-11, 50 |
| 高碳奥氏体耐热钢晶间腐蚀行为与纳米化快速脱敏的研究进展 |
| Research Progress on Intergranular Corrosion Behavior and Rapid Desensitization by Surface Nanocrystallization of High-carbon Austenitic Heat-resistant Steel |
| 投稿时间：2022-01-06 修订日期：2022-03-04 |
| DOI：10.16490/j.cnki.issn.1001-3660.2022.03.001 |
| 中文关键词: 奥氏体耐热钢 晶间腐蚀 表面纳米化 快速脱敏 临界变形量 |
| 英文关键词:austenitic heat resistant steel intergranular corrosion surface nanocrystallization rapid desensitization critical deformation |
| 基金项目:国家自然科学基金(51471072);广东省基础与应用基础研究基金(2019A1515011683) |
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| 中文摘要: |
| 在传统304不锈钢基础上开发的高碳奥氏体耐热钢Super304H具有优异的高温性能，被大量应用于制造超超临界火电机组的过热器管和再热器管，然而其高碳含量带来的高晶间腐蚀敏感性问题已成为影响Super304H钢安全运行的关键因素。为此，研究人员从Super304H奥氏体耐热钢管材的成分优化、热处理工艺改进，特别是脱敏自愈合工艺调控与机理等几个方面进行了研究，寻求降低该材料晶间腐蚀敏感性的方法。在简介奥氏体耐热钢晶间腐蚀机理的基础上，重点综述了近年来Super304H钢晶间腐蚀防护各类对策的研究进展。目前传统的选取C含量下限、添加Nb稳定化元素和双固溶处理等常规手段，都无法有效遏制Super304H钢在高温服役过程中因M23C6的快速形成而引发的高晶间腐蚀敏感性，只能另辟蹊径。通过采用表面喷丸纳米化工艺，不仅加快富铬碳化物M23C6的形成，而且也促进了贫铬区的自愈合，实现了快速脱敏的目标。然而，严重的塑性变形组织在高温时效早期便出现富铬sigma相快速析出的异常现象，导致Super304H钢的腐蚀性能劣化。对此，进一步调节喷丸处理的工艺参数，在避免sigma相析出的前提下获得贫铬区快速脱敏自愈合的最优脱敏工艺，并维持了纳米晶的稳定性，而且所进行的脱敏处理没有对不锈钢的均匀腐蚀性能带来负面影响。最后展望了奥氏体耐热钢晶间腐蚀防护技术在超超临界机组领域的发展方向。 |
| 英文摘要: |
| The high-carbon austenitic stainless steel Super304H developed on the basis of traditional 304 stainless steel has excellent high-temperature performance and is widely used as superheater and reheater tubes in the ultra supercritical units. However, its high intergranular corrosion sensitivity (IGCS) caused by the high carbon content has become a key issue affecting the safe operation of the ultra supercritical units. Researchers have made a comprehensive studies, like composition optimization, improvement of heat treatment and adjustment of self-healing technics, trying to seek an effective method to reduce the IGCS of Super304H steel. After a brief introduction of the mechanism of intergranular corrosion of austenitic stainless steel, this paper focused on the research progress of various countermeasures for intergranular corrosion protection of Super304H steel in recent years. Conventional methods such as selecting the lower limit of C content, adding Nb stabilizing element and double solution treatment were found to be not able to curb completely the IGCS caused by the formation of M23C6 of Super304H steel, so another way has to be explored. Surface nanocrystallization by shot peening (SP) was found to accelerate the formation of M23C6 and the healing of chromium depleted zones of Super304H steel, and as a result, rapid desensitization could be obtained. However, severely deformed microstructure by SP triggered the abnormal precipitation of chromium-rich sigma phase during aging, resulting in the deterioration of intergranular corrosion resistance of the steel. Therefore, a critically unsaturated SP process that could avoid the abnormal sigma-phase precipitation was investigated by optimizing the SP technics. The obtained SP process is the optimal one for rapid self-healing and desensitization in the chromium-depleted zones of Super304H steel. Meanwhile, the surface nanocrystalline can keep a good thermal stability and the desensitization treatment does not have a negative impact on the uniform corrosion performance of the Super304H steel. Finally, the development direction of intergranular corrosion protection technology of austenitic heat-resistant stainless steel in the field of ultra-supercritical units is prospected. |
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