保温层下腐蚀（CUI）是流程工业设备完整性管理的重要内容。本专题参考 API RP 583、NACE SP0198、EFC Publication No.55 以及 GB/T 4272、GB 50264、SH/T 3010 等标准与规范，并结合硕屋科技产品检测数据及工程应用经验，介绍CUI形成机理、系统控制方法及保温材料在其中的作用。
CUI is a critical concern in process industry asset integrity management. This topic references API RP 583, NACE SP0198, EFC No.55, GB/T 4272, GB 50264, and SH/T 3010, combined with Shuowu product test data and engineering experience.
在炼油、石油化工、电力及LNG等流程工业装置中，保温系统承担着降低热损失、保障工艺稳定运行的重要作用。但当外部水分进入保温层并长期滞留时，金属表面可能形成持续的腐蚀环境，这种发生在保温系统内部的外部腐蚀被称为保温层下腐蚀（CUI）。
由于腐蚀位置被保温层覆盖，在设备运行期间通常难以及时发现，因此成为流程工业设备完整性管理重点关注的外部损伤机理之一。
In refinery, petrochemical, power, and LNG process plants, insulation systems reduce heat loss and ensure stable operation. When external moisture enters and persists within the insulation, a sustained corrosive environment can form on metal surfaces — this is CUI. Because the corrosion is hidden beneath insulation, it often goes undetected during operation.
设备投入运行后，工程师能够看到的通常只有外护层，而真正发生腐蚀的位置位于保温系统内部。即使设备外观保持完整，金属表面仍可能已经发生局部腐蚀、壁厚减薄甚至点蚀。
因此，许多CUI只有在计划检修、拆除保温或发生泄漏后才能确认。相比普通外部腐蚀，其修复往往需要同时恢复整个保温系统，增加检维修工作量和停工影响。
After equipment enters service, only the outer cladding is visible — the corrosion site lies within. Even when the exterior appears intact, localized corrosion, wall thinning, or pitting may already be underway. Many CUI cases are only confirmed during planned shutdowns, insulation removal, or after leaks occur.
CUI属于电化学腐蚀，其形成需要同时具备水分、氧气及适宜的腐蚀环境。降雨、冷凝、冷却塔漂水、消防喷淋及工艺介质泄漏等外部水源，可通过外护层接缝、穿透点、机械损伤或密封失效进入保温系统。
当水分长期滞留于金属表面时，腐蚀便可能持续发展，因此控制外部水分侵入是国际腐蚀控制标准长期关注的重要内容。
CUI is electrochemical corrosion requiring moisture, oxygen, and a suitable corrosive environment. Rain, condensation, cooling tower drift, firewater, and process leaks enter through cladding seams, penetrations, mechanical damage, or seal failure. Persistent moisture on metal surfaces drives ongoing corrosion.
国际腐蚀控制标准提出，应采用系统方法开展CUI控制。完整保温系统通常包括防腐层、保温材料、外护层、节点密封、规范施工及检查维护等多个环节，各组成部分共同影响系统长期运行可靠性。
International standards recommend a systems approach to CUI control. A complete insulation system includes coating, insulation material, cladding, joint sealing, quality installation, and inspection — all contributing to long-term reliability.
金属表面第一道屏障
First barrier on metal
绝热 + 抗水分渗透
Thermal + moisture barrier
机械 + 防水保护
Mechanical + waterproof
消除水分侵入点
Eliminate ingress points
保证设计意图实现
Ensure design fidelity
全生命周期管理
Lifecycle management
保温材料是保温系统的重要组成部分。除满足绝热性能外，国际腐蚀控制标准建议综合考虑材料耐久性、吸水特性、可溶性离子含量及与防腐体系的相容性。对于长期高湿环境，具有整体憎水性能的保温材料能够降低材料受潮后的含水量，更适用于此类工况。
Insulation material is a key system component. Beyond thermal performance, standards recommend evaluating durability, water absorption characteristics, leachable ion content, and coating compatibility. For persistently humid environments, fully hydrophobic insulation reduces moisture content after wetting.
低导热系数是保温材料的基础要求，直接影响热损失和系统能效。
Low thermal conductivity is fundamental, directly affecting heat loss and energy efficiency.
整体憎水性能可降低材料受潮后的含水量，减少CUI发生的湿度条件。
Reduces moisture content after wetting, minimizing the humidity conditions for CUI.
控制可溶性氯离子等腐蚀性离子含量，降低电化学腐蚀风险。
Controlling leachable chloride and corrosive ions reduces electrochemical corrosion risk.
材料在长期高湿、温度波动工况下保持结构和性能的稳定性。
Maintains structural and performance stability under persistent humidity and thermal cycling.
CAS-A0TH采用纳米孔硅基复合结构，在保持优异绝热性能的同时，整体具有优异的憎水性能，可减少液态水进入材料内部。
产品适用于石油化工、电力、LNG接收站及海洋工程等长期高湿环境，可作为完整保温系统的重要组成部分，与防腐层、外护层及规范施工共同提升系统长期运行可靠性。
CAS-A0TH features a nanoporous silica composite structure, delivering excellent thermal performance with full hydrophobicity to reduce liquid water ingress. Suitable for petrochemical, power, LNG, and marine environments, it serves as a key component of the complete insulation system.
查看 CAS-A0TH 完整技术参数、工程案例及应用指南
View full technical specifications, case studies, and application guide
注：参考文献按首字母排序。
Note: References are listed in alphabetical order.