AP1000主管道焊接接头微观组织和性能试验

Research on the microstructure and properties of welded joints of primary coolant pipes in AP1000 nuclear power plant

在优化焊接工艺参数的基础上，系统分析了AP1000核电站锻造316LN主管道焊接试验件的母材、热影响区及焊缝的微观组织形貌和拉伸性能。结果表明，焊接接头组织沿主管道壁厚方向均匀分布，存在明显晶粒粗化的热影响区。焊缝金属由柱状奥氏体＋残留铁素体组成，铁素体数位于8～10FN之间，属于典型的铁素体一奥氏体结晶模式，不存在碳化物及氮化物析出。在核电站设计工况350℃下，抗拉强度达到450MPa。

Focused on the microstructure and properties of primary coolant pipes welded joints in AP1000 nuclear power plant in the paper. The microstructure of the base metal, heat affected zone and the weld of the forged 316LN stainless steels was distributed evenly and had the same variation along the thickness of the pipe. Coarsened austenitic grain was observed in the heat affected zone. The weld metal consisted of columnar austenite and residual ferrite without any carbide or nitride being found. The ferrite number was about 8 to 10. The tensile properties of the weld metal were very well. Tensile strength arrived 450 MPa at 350 ℃。