厚壁P92钢管道焊接接头中频感应热处理的应用实践

火力发电厂1000 MW机组主蒸汽厚壁P92钢管道焊接接头焊后热处理在火电建设工程中技术要求较高，尤其是壁厚大于100 mm的P92钢管道焊接接头。通过中频感应加热对1000 MW二次再热机组的壁厚为118 mm的主蒸汽P92钢管焊接接头进行了管道试样的焊后热处理。结果表明，热处理后焊缝及母材组织正常，焊缝硬度符合标准要求；同时依据试样管焊后热处理发现的问题提出了优化措施，在施工过程中降低升温速度和恒温温度、增加保温宽度，实现了121个同类型焊接接头焊后热处理一次合格。厚壁P92钢管道焊接接头中频感应热处理方案的成功应用，可为后续同类型部件的焊后热处理提供借鉴。

Application practice of medium frequency induction heat treatment for welded joint of thick-wall P92 steel pipe

In view of the high technical requirements of post-weld heat treatment for main steam thick-wall (especially for that with wall thickness greater than 100 mm) P92 steel pipe welded joint of 1000 MW unit in thermal power plant, post-weld heat treatment of the pipe specimen was carried out for the main steam P92 steel pipe welded joint with 118 mm wall thickness of a 1000 MW secondary reheat unit by medium frequency induction heating. The results show that after the post-weld heat treatment, the microstructures of the weld and the base material are normal, and the hardness of the weld meets the standard requirements, and after further optimization of the heat treatment by appropriately reducing the heating rate and constant temperature and increasing the width of heat preservation, 121 heat-treated welded joints of the same type are one-time all qualified in the pipeline construction process. The successful application of medium frequency induction heat treatment scheme for welded joints of thick-wall P92 steel pipe can provide reference for the subsequent post-weld heat treatment of the same type of parts.