Residual stress reduction in dissimilar metals weld

• Published in: Journal of manufacturing processes 2021-04, Vol.64, p.1462-1475
• Main Authors: Eisazadeh, H., Aidun, D.K.
• Format: Article
• Language: English
• Subjects: Dissimilar metals weld; Rapid cooling; Residual stress; Stress reduction
• ISSN: 1526-6125; 2212-4616
• DOI: 10.1016/j.jmapro.2021.02.062

Conventional methods such as post-weld heat treatment is not capable to reduce residual stress (RS) in dissimilar metals weld (DMW) to the same extent as in similar weld due to mismatch between thermal expansion coefficient of base metals. The objective of this study to understand the effects of a modern in situ technique, called CO2 rapid cooling, on mechanism of RS redistributions in both similar and dissimilar metals welds. More focus of this investigation is given to the DMW. A thermo-mechanical numerical model is developed to investigate the effectiveness of various CO2 rapid cooling parameters such as power, radius, off-center, and location of the CO2 nozzle on RS distribution. The model is tested and validated with experimental data obtained from neutron diffraction measurement. Overall, this study shows that the CO2 cooling application can produce a significant RS reduction in similar weld as well as DMW. It shows that smaller CO2 nozzle can lead to lower RS magnitude considerably; however, it is not always capable to produce favorable RS distribution. In addition, since the RS distribution is asymmetric in a DMW, the implementation of CO2 cooling technique to mitigate RS need not be symmetric or uniform with respect to the weld center line. Based on the results, further recommendations to minimize RS in welded parts are provided.