In the narrow gap welding joints of dissimilar steels, carbon migration happens due to the different components of dissimilar steels. Ferrite with low hardness is found in the carbon depleted zone of a real dissimilar welding high temperature component, which influences the mechanical properties of the welding joint. Bead-on-plate specimens with different weld bead configurations are designed to study the influence factors of carbon migration and the formation of ferrite in carbon-depleted zone. Carbon migration is found to happen during the temper process by metallographic observation. With the method of micro-hardness test and electron probe microanalysis, it is found that fusion ratio has a great influence on carbon migration. The specimen with three layers of welding beads suffers a severe carbon migration phenomenon, ferrite appears in the carbon-depleted zone, with a great decrease of micro-hardness. Electron probe microanalysis indicates that the multilayer intersection has a low fusion rate, the content of Cr across the fusion line is significantly different, which leads to a steep gradient of the activity of C. Carbon migration is severe at this area, which will have a deleterious effect on the mechanical properties of dissimilar welding joints.
ZHENG Yunwei
,
CAI Zhipeng
,
HE Yuchen
,
LI Kejian
,
PAN Jiluan
. Study on the Influence of Fusion Ratio on Carbon Migration Phenomenon in the Narrow Gap Welding of Dissimilar Steels[J]. Journal of Mechanical Engineering, 2016
, 52(12)
: 74
-80
.
DOI: 10.3901/JME.2016.12.074
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