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对AP1000核岛设备堆芯补水箱简体内壁不锈钢堆焊层下大量横向缺陷的产生原因进行深入分析,结果表明,由于施焊时预热温度偏低导致焊接热影响区组织淬硬程度较大及该区域扩散氢含量较高,在焊接应力的作用下从焊接热影响区的锻件母材表面或近表面的组织疏松或夹杂物等薄弱区域启裂,向简体锻件母材的厚度方向扩展形成的冷裂纹。针对裂纹产生的原因,提出了防止措施。
The causes of a large number of transverse defects under the stainless steel overlay in the AP1000 core island recharging tank are analyzed in depth. The results show that due to the low preheating temperature during welding, the tissue hardening in the heat affected zone The hydrogen content is high in this region. Under the action of welding stress, the area of cracking is cracked from the weak area such as the loose or inclusions of the surface of the forged base metal or the inclusions in the welded heat-affected zone, and expanded to the thickness direction of the simplified forged base metal Cold crack. Aiming at the cause of the crack, a preventive measure is put forward.