Abstract:

The high cycle fatigue properties for submerged arc welding(SAW)  joints and tungsten inert gas(TIG) welding  joints of 25Cr2Ni2MoV simulating product of nuclear power low pressure turbine rotors were researched and compared.and the TIG welding joints were  found to be better.The interior crack origins of SAW were porosities and inclusions, while these of TIG were porosities. For the conditions of porosities,an approach to evaluate the high cycle fatigue properties was established with the measurement and calculation of characteristic size of crack initiation zones (without crack origins) and crack initiation rate. For the researched welding joints, white-light interfering profilometer was used to measure the characteristic size,and the crack initiation rate of TIG joint is lower, which is in agreement with the experiments.

Key words: welded nuclear rotor;high , cycle fatigue;characteristic size;crack , initiation rate

摘要：

研究并对比了25Cr2Ni2MoV焊接转子模拟件埋弧焊和氩弧焊接头高周疲劳性能,发现氩弧焊接头高周疲劳性能优于埋弧焊接头高周疲劳性能。观察高周疲劳断口发现：埋弧焊接头高周疲劳裂纹启裂于气孔与夹杂物；而氩弧焊接头启裂于气孔。针对内部启裂源为气孔的情况，提出通过测量启裂区(不含启裂源)特征尺寸求得高周疲劳裂纹启裂速率的途径来评价高周疲劳性能。通过白光干涉形貌仪测量启裂区特征尺寸，发现埋弧焊接头高周疲劳裂纹启裂速率高于氩弧焊接头高周疲劳裂纹启裂速率，与实际高周疲劳性能测试结果一致。

关键词: 核电焊接转子, 高周疲劳, 特征尺寸, 启裂速率