E16-25MoN welding wire cladding layer was prepared by using argon tungsten arc welding,and the tensile experiments at different temperatures and strains were carried out by using Gleeble thermal simulation machine.The results show that the high temperature ductility-dip crack(DDC)sensitivity of the deposited metal is high in the range of 850-1150 ℃,and the high temperature DDC sensitivity of the deposited metal is the highest at 1000 ℃,and the critical strain at cracking at this temperature is lower than 6％.Through the microstructure analysis,it is found that the production of high temperature DDC is affected by the flat morphology of grain boundary and the grain boundary precipitates.At high temperature,the precipitates at the grain boundary hinder the movement of dislocations,resulting in stress concentration and eventually cracking,while the flat grain boundaries provide favorable conditions for crack propagation.
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