异种钢焊接接头蠕变过程的有限元模拟

异种钢焊接接头常应用于高温下工作的大型构件，其蠕变特性和持久性能对结构的安全性具有重要意义。常规的蠕变试验和高温持久试验仅适用于均匀材料，对非均匀的异种钢接头存在局限性。为了解决该问题，针对某种构件上采用的含有过渡层的马氏体钢与珠光体钢异种金属接头进行了有限元建模。分别利用K-R蠕变损伤模型和改进的θ Projection模型进行模拟计算，并且对比了非均匀结构与均匀的焊缝、过渡层和母材的蠕变特性。对比发现，非均匀结构中抗蠕变性能较弱的过渡层部分的蠕变速率要大于均匀的过渡层材料的蠕变速率，这说明材料的不均匀性会带来附加的蠕变损伤。因此，仅通过均匀材料的蠕变试验来预测非均匀结构的寿命是不可靠的，应采用蠕变试验与有限元计算相结合的方法进行非均匀结构的寿命预测。

Finite Element Analysis of Creep Behavior of Dissimilar Steel Welded Joint

Dissimilar welded joints are often used in large components working under high temperature. The creep rupture property of dissimilar welded joint is of great significance for the safety of the structure. Conventional creep test and creep rupture test are only applicable to homogeneous materials, but not to inhomogeneous materials. In order to solve this problem, a finite element model was built according to a dissimilar welded joint used in a real component which made up of martensitic steel and pearlitic steel.By using K-R creep damage model and advanced θ Projection model respectively, it is found that the creep rupture property of inhomogeneous dissimilar joint is different from that of homogeneous base metal, weld metal and transition layer. The creep rate of transition layer in dissimilar joint is higher than the same homogeneous material, which means the heterogeneity of structure leads to additional creep damage. The conclusion can be made that it is unreliable to predict the creep life of a dissimilar steel structure only according to creep rupture tests on different parts for homogenous materials,the finite elements analysis based on creep rupture test is also necessary.