异种耐热钢焊接接头低塑性蠕变失效力学因素的研究

INFLUENCE OF MECHANICAL FACTOR ON LOW DUCTILE CREEP FAILURE FOR DISSIMILAR HEAT RESISTANT STEEL WELDED JOINTS

用有限元法计算了异种耐热钢接头邻近焊缝界面低强度材料区的蠕变应变分布，建立了蠕变拘束区（ＣＲＺ）应力三轴度（σ＿ａｖ／σ）与蠕变应变速率的比值（εｗ／εｂ）之间的数学关系模型，并通过蠕变断裂试验证明了数学模型的正确性。理论分析和试验结果表明，焊缝界面低强度材料蠕变拘束区的应力三轴度是接头发生低塑性蠕变失效的主要力学因素。

The creep strain distribution in the low strengt h material adjacent to weld interface of dissimilar heat resistant steel welded joint is investigated by finite element method,and the mathematical model betwe en the stress triaxiality （σ＿ａｖ／σ）and the ratio of creep s train rate（ εｗ／εｂ）i s established.It was shown from the analytical result that the stress triaxialit y in the creep restraint zone(CRZ)of low strength material adjacent to the inter face is a major mechanical factor of low ductile creep fracture for the welded joint.The theoreticl analysis agrees with the creep fracture test results.