热均衡加热法在超大型压力容器修复现场热处理中的应用

超大型、超高压压力容器的现场修复,因体积庞大、超大壁厚,现场修复一直是设备检修中的难题,而热处理是修复部位质量的保证,更是修复工作成功的关键。受现场施工电源和复杂环境等因素限制,进行容器的整体热处理根本不可能,而局部热处理又容易导致容器变形,加热源的分布、温度场监测、加热的时间控制是保证热处理成功的主要手段。广东某电厂660 MW亚临界燃煤机组汽包,在2017年级检修过程中发现汽包焊缝有大量的超标缺陷,修复时间长达3个多月,通过采用热均衡法对汽包分多段进行热处理,很好地解决热处理中防止汽包变形的难题。该文就此次汽包修复过程中的热处理工艺作一些介绍,希望能对超大型容器的焊缝修复过程提供一些有益的借鉴。

The on-site repair of super-large and ultra-high pressure pressure vessels has always been a difficult problem in equipment maintenance because of its large volume and super wall thickness, and heat treatment is the key to the success of the repair work. Heat treatment is limited by on-site construction power supply and complex environment, so it is impossible to carry out overall heat treatment, while local heat treatment can easily lead to container deformation. In the process of heat treatment, the distribution of heat, the control of temperature field and the control of heating time are the main means. During the inspection and repair of the steam drum of the 660 MW subcritical unit of a power plant in Guangdong, it was found that there were a large number of over-standard defects in the weld of the drum, and the repair time was more than 3 months. Using the heat balance method to heat treat the drum in multiple stages, the problem of drum deformation in heat treatment was well solved. This paper introduces the heat treatment process in the process of steam drum repair, hoping to provide some useful reference for the weld repair process of super-large vessels.