反应堆压力容器J型焊缝焊条电弧焊缺陷产生机理及防治措施研究

Research on the Mechanism and Prevention Measures of Defects in J-Weld of Reactor Pressure Vessel

反应堆压力容器是反应堆冷却剂系统的重要承压设备。CRDM贯穿件通过J型焊缝与顶盖连接,结构形式复杂、拘束度大、残余应力大,J型焊缝的焊接技术是反应堆压力容器制造的关键。由于其结构特点,操作更为方便灵活的焊条电弧焊方法被广泛应用于该焊缝的焊接。因其特殊工况需要,耐腐蚀性能更优的ENiCrFe-7型镍基合金焊条作为其焊接填充材料。因其材料特性,焊接时容易出现热裂纹、气孔、夹杂等缺陷。尤其在J型焊缝这类拘束应力大的接头中,其制造难度进一步增大。本文对J型焊缝从结构特点、镍基合金材料的特性、工艺控制要点、过程管控措施等方面展开系统分析,并制定相应的控制措施,以达到提升J型焊缝焊接质量的目的。

Reactor pressure vessel is an important pressure equipment of reactor coolant system.CRDM penetration is connected to the top cover through J-weld,which has complex structure,large constraint and large residual stress.The welding technology of J-weld is the key to the manufacture of reactor pressure vessel.Because of its structural characteristics,the electrode arc welding method,which is more convenient and flexible in operation,is widely used in the welding of this weld.Due to its special working conditions,ENiCrFe-7 nickel-based alloy electrode with better corrosion resistance is used as its welding filler material.Due to its material characteristics,it is easy to have defects such as hot cracks,pores and inclusions during welding.Especially in joints with high constraint stress such as J-welds,the manufacturing difficulty is further increased.In this paper,J-welds are systematically analyzed from the aspects of structural characteristics,characteristics of nickel-based alloy materials,process control points,process control measures,etc.,and corresponding control measures are formulated to achieve the purpose of improving the welding quality of J-welds.