NiCrMoV钢焊接转子接头韧性研究

针对核电低压焊接转子用NiCrMoV钢焊接接头的韧性进行研究,分别对母材、接头热影响区、焊缝内柱状晶区、焊缝内细晶区等各区域进行冲击韧性测试,结合断口处形貌及微观组织特征,研究韧性与组织的相互关联机制。结果表明,焊接接头各区域的冲击性能均满足要求,热影响区冲击性能波动较大,焊缝柱状晶区沿晶界开裂使得其冲击性能较弱。裂纹沿柱状晶晶界扩展及柱状晶晶界上少量碳化物析出是焊缝内柱状晶区域韧性较低的主要原因。

Investigation on toughness of NiCrMoV steel welded rotor joint

The toughness of NiCrMoV steel welded joints for nuclear power low-pressure welded rotor is investigated. The impact toughness tests are carried out about the base material,joint heat affected zone,columnar crystal zone in weld,and the fine grain zone in weld. Combining with the fracture morphology and microstructure characteristics,the interrelationship mechanism between resilience and organization is studied. The results show that the impact property of each zone in welded joints can meet the requirement,but the impact property of the heat-affected zone fluctuates greatly. The cracking of the columnar crystal zone along the grain boundary makes the impact property weak. The cracks extend along the columnar grain boundary and a small amount of carbide precipitate on the columnar grain boundary,which is the main reason for the low toughness of the columnar crystal region in the weld.