AP/CAP机组控制棒驱动机构密封焊缝激光焊接技术研究

Research on Laser Welding for Seal Weld of AP/CAP Unit Control Rod Drive Mechanism

针对AP/CAP机组寿期内控制棒驱动机构多次更换的需求,为了降低焊接变形及残余应力,将激光技术引入到控制棒驱动机构密封焊缝的焊接中,并在模拟件上共进行了7次切-焊循环。结果表明;激光焊接方法可行;填充环结构设计合理,焊道成形良好,余高均匀,未发生未焊透、未熔合、咬边等情况;焊缝渗透检测也无任何缺陷显示;各次切-焊循环中模拟件下部唇边外径变形量基本处于稳定状态,尤其是前4次循环,外径仅与设计值相差0.02 mm;焊缝残余应力为拉应力,且随着循环次数增加呈减小的趋势。

For the requirement of serval replacement of AP/CAP unit control rod drive mechanism, laser technology was introduced into the seal weld welding of the control rod drive mechanism to reduce the welding deformation and residual stress, and seven cut-welding cycles were carried out on the mockups. The results show that the laser welding method is practicable, the structure design of the filled ring is reasonable, the weld bead forming is good, the reinforcement is uniform and no incomplete penetration, no fusion, no undercut occur. The penetration test of the weld shows no defects. For each cut-welding cycle, the outer diameter of the down lip remains constant state, especially in the first four cycles, the diameter is only 0.02mm different from the design value. The residual stress is tensile stress and decreases with the increase of cycle time.