Application of High Temperature Corrosion-Resistant Materials and Coatings Under Severe Corrosive Environment in Waste-to-Energy Boilers

Corrosion-resistant materials (CRMs) and coatings are key technologies to increase power generation efficiency and reduce maintenance in waste-to-energy (WTE) plants. Corrosion environment became severe as steam temperatures have increased. The steam condition of more than 400 °C/3.9 MPa became possible in WTE boilers by using highly durable corrosion-resistant coatings, such as thermal spray of Al/80Ni20Cr alloy, HVOF-sprayed NiCrSiB alloy, Alloy 625 weld overlay for waterwall tubes and also superheater tubes. Also, the use of 310S type stainless steels and high Cr-high Mo-Ni base and high Si-Cr-Ni-Fe alloys have progressed because of a better understanding of corrosion mechanisms. Furthermore, high durability coatings using cermet and ceramic materials were applied to high temperature superheaters. This paper describes the major developments and the application of CRMs and coating technologies in the last 30 years in WTE plants, the corrosion mechanisms of alloys, the deterioration mechanisms of spray coating layers, and future subjects for the development of corrosion-resistant materials and coatings.     

新型沥青涂覆设备的应用

在110 kV及以上高压电力电缆的生产中,金属护套的防腐层的涂覆工艺是一道重要的工序。老式的沥青涂覆装置存在着生产连续性差,防腐层涂抹不均、对生产机台污染严重等缺点。本文介绍一种新型沥青涂覆装置,它是通过电动装置将加热熔化好的沥青液传送到流槽中,由流槽传送后均匀地涂覆在金属护套上。沥青的加热方式为非接触式的远红外加热,改变了传统的接触式加热,提高了加热效率和安全系数,减少了对生产机台的污染。     

快速凝固耐热铝合金耐蚀性能的研究

采用腐蚀失重法和极化曲线，对比研究了FVS0611，FVS0812，2618，2618 Sc，2014，6061合金在人工模拟海水和海洋环境中的耐蚀性能。结果表明：2014，2618和2618 Sc腐蚀较严重；RS／PM生产的FVS0611，FVS0812和6061有较小的腐蚀速率，出现明显的钝化现象；并因为加工残余应力导致出现钝化-腐蚀-再钝化现象。     

船舶及海洋工程用耐蚀E36钢板的性能分析

采用耐蚀微合金化、冶金质量控制、夹杂物改性及组织控制的耐蚀性改进技术思路,对E36钢进行了耐蚀性改进研究,并结合控轧控冷工艺对耐蚀E36钢板进行试制。结果表明,微合金化有助于提高钢的自腐蚀电位,高洁净度控制和夹杂物改性可降低点蚀敏感性,组织控制可减小复相组织选择性腐蚀倾向;试制钢板耐海水腐蚀性能较传统E36钢板有了大幅提升,其在酸性氯离子环境中的腐蚀速率降至0.59mm/a,耐蚀性较传统E36钢提高约4.6倍。     

污水处理罐的防护措施

分析了1000m~3污水处理罐采用涂料、阴极保护联合防护的失效原因及防护措施.     

原油储罐底板腐蚀穿孔的原因分析

分析了一座原油储罐在采用导静电涂料与阴极保护相结合的防腐蚀措施下发生腐蚀的原因，提出了相应的解决方法。建议使用富锌涂料，按比例加导电物质，不能片面追求导电率而提高石墨粉的添加量；建议探索绝缘性涂料加牺牲阳极的保护方法。     

耐侯钢生产实践与工艺优化

通过对耐侯钢内部氧化物超标原因的分析，提出了有针对性的工艺改进措施，取得了良好的效果。     

Analytical method of calculating preheating temperature in order to avoid cold cracking

Summary

The IIW method is shown to be one of the most precise and that it may be programmed to advantage.     

金属表面热喷涂陶瓷层的防腐蚀性能研究现状与展望

金属基体涂覆陶瓷涂层后具有优异的耐腐蚀性能。从陶瓷涂层的耐蚀性、对金属基体耐蚀性的改善和提高热喷涂陶瓷涂层防腐蚀性能的后处理方法如封孔方法等方面概述了陶瓷涂层对金属基体的防腐蚀性能研究现状,在与电镀硬铬防腐蚀性能比较的基础上,指出了目前研究中存在的问题,并对未来的研究进行展望。     

Densification of plasma-sprayed titanium and tantalum coatings

Thermal spraying of corrosion- resistant coatings of titanium and tantalum is difficult; dense coatings are not produced, and oxidation of these metals increases coating porosity. In this study, oxidation during plasma spraying was reduced with a shrouding system. Porosity and oxide content also were minimized by optimizing the spraying parameters. After optimization, the coatings still had open porosity and thus were incapable of protecting the substrate material against corrosion in water solutions containing 3 % NaCl. Therefore, posttreatments for improvement of corrosion resistance were studied. Electron beam fusion produced corrosion resistance equal to or better than that of bulk commercial samples of titanium and tantalum.