600 MW超临界机组SA335-P91钢免根透焊接工艺控制

SA335-P91 steel root-penetration prevention welding process control of 600 MW supercritical unit

在开封火电厂2×600 MW扩建工程2#机组中,壁厚δ≥70 mm的P91壁厚大径管共计53道。施工中首次采取免根透、严格控制工艺过程方法,确保P91厚壁大径管的焊口质量。主要从保证充氩质量、严格监控焊接工艺参数、选择适当的焊接规范等方面进行控制,在施工过程设专人旁站监督、记录。同时对工艺控制过程做了大量工作,如:精确计算焊接层数、绘制焊缝示意图、管材性能分析、焊接、热处理工艺性分析、旁站记录表设计、增加坡口着色检验、根部双重保护、准确测温(增加远红外测温仪)、热处理温差控制、加热器、保温棉布置包扎策略等。

The 2nd unit of Kaifeng Thermal Power Plant Expansion Project has 53 pieces P91 large diameter pipes with the wall thickness no less than 70mm.In the course of construction of this unit,the root-penetration prevention welding method is used for the first time.The process is strictly controlled to ensure the welding quality of P91 large diameter thick wall pipe.The paper insists on that the control should be done by argon quality assurance,strict control of welding parameters,the appropriate welding regulations and so on.The specially-assigned person would supervise and record the construction process at site.At the same time a lot of work should be done to control the welding technique in the construction process,such as：accurate calculation of welding layers form,weld mapping diagram,pipe performance analysis,welding and heat treatment analysis,site supervision log design,increasing groove stain test,double protection of the roots and accurate temperature measurement（by far infrared thermometer）,heat treatment temperature control,heaters,insulation and other strategies.