Residual stress and microstructural features of friction-stir-welded GL E36 shipbuilding steel

Abstract

The purpose of the present study was to fulfil the knowledge gap concerning residual stresses evaluation of friction stir welded GL E36 shipbuilding steel. Plates of 6 mm thickness were welded using two different welding speeds (1 and 3 mm s−1) at a constant rotational speed of 500 rev min−1. This led to different thermal cycles and the objective is to analyse the resulting microstructures and residual stress states. Therefore, in this work, residual stresses were evaluated by X-ray diffraction; metallography and microhardness testing were performed to support these measurements. Results showed that welds produced with different heat inputs have distinguishable residual stress distributions. Increases in the welding speed led to higher residual stress and microhardness in the stir zone.

Replacement of Gas Metal Arc Welding by Friction Welding for Joining Tubes in the Hydraulic Cylinders Industry

“…On the other side, Figure 7c) shows the TMAZ tube microstructure which was composed by coarse pearlite, grain boundary and Widmanstättenn ferrite. Acicular ferrite is a desirable microstructural feature due to its relation with good toughness; however, grain boundary ferrite can adversely affect this property 8 . Still, the acicular ferrite with finer microstructure would prevent the initiation and propagation of cracks 20 .…”

“…In addition, fusion welding may also be related to unhealthy environments and exposure to radiation 7 . Friction based processing is characterized by solid state joining methods that can weld several materials both ferrous based alloys 8 and non-ferrous alloys such as titanium 9 and nickel based alloys 10,11 . As potential advantages over conventional welding could be the possibility of achieving an excellent joint quality, joining of dissimilar materials, cost savings and increased mechanical properties 12,13,14 .…”

The effect of hydrogen on the fracture toughness of friction‐stir welded API 5L X70 pipeline steels

“…The residual stress line profiles result from the thermomechanical cycle during FSW and the subsequent phase transformations during cooling. 58,59 The residual stress distribution is typical for FSW, [59][60][61][62][63] with compressive residual stresses arising along with both welding directions in the SZ. The distribution of the longitudinal stress component is asymmetric, and a tensile peak occurs on the advancing side, whereas low longitudinal compression is verified on the retreating side.…”

Influence of Residual Stress on Fatigue Weak Areas and Simulation Analysis on Fatigue Properties Based on Continuous Performance of FSW Joints

“…The fatigue properties of aluminum alloy FSW joints are also affected by the residual stress [2][3][4]. The residual stresses of aluminum alloy welded joints are dependent on the welding parameters and their distribution has a typical "M" profile [10][11][12][13]. The locations of the maximum residual tensile stress are different for different alloy joints.…”