Three-dimensional analysis of mesoscale deformation phenomena in welded low-carbon steel

A three-dimensional numerical analysis of the mesoscale deformation behavior of welded low-carbon steel specimens is performed. A weld-affected polycrystalline microstructure is designed to reproduce gradual changes of the grain size throughout the base metal and heat-affected zone regions. A mathematical model based on a double-limit yield criterion is used to describe Lüders band propagation characteristic of this type of steel. The effects of the free surface, grain boundaries and interfaces between the fusion zone and the heat-affected zone, and between the heat-affected zone and the base metal are discussed.

► Mesoscale deformation phenomena in welded low-carbon steel specimens are analysed numerically.
► A polycrystalline microstructure is introduced in calculations explicitly.
► A double-limit yield criterion is used to describe Lüders band propagation.
► Several kinds of interfaces are found to be responsible for different degrees of stress concentration at the mesoscale level.
► Cracks are expected to occur on the surface under tension and in the bulk under compression.