Influence of transition way of carbon and chromium on microstructure and thermal fatigue property of Cr5 series deposited metal

摘要

In the present investigation, carbon and chromium were added into the submerged arc flux-cored wire in two different ways for the Cr5 deposited metal. The chromium carbide was added into flux-cored wire 1#. The graphite and chromium were added into flux-cored wire 2#. The results showed that numerous white hard phases with higher alloy content dispersed in the deposited metal 1#, in which the element distribution and microstructure were inhomogeneous than that of deposited metal 2#. After experiencing the same thermal cycles, the cracks initiated early, and grew quickly in the specimen 1#. In the process of thermal fatigue, cracks grew along the boundaries of the hard phases. It is expected that the serious composition segregation was the main reason of resulting in fast growth of cracks in deposited metal 1#. It was effective for weakening the fatigue crack tendency that alloy composition distribution, microstructures. It is consistent with the practical application.Changing the addition way of alloy is a new effective way for grain refinement and microstructure uniformity instead of modifying agent and external excitation.