A Phenomenological Study of Weld Discontinuities and Defects in Resistance Spot Welding of Advanced High Strength TRIP Steel

A Novel Shim-Assisted Resistance Spot Welding Process to Improve Weldability of Medium-Mn Transformation-Induced Plasticity Steel

“…Since they produced the different nugget sizes and tremendously different weld surface (expulsion, cracking etc. in Figure 5), these should be related to the different thermophysical properties of all the materials between the electrodes in the three set-ups, [11] as also given in Figure 2. Table III summarizes the electrical resistivity, thermal conductivity, thermal expansion coefficients, solidus temperatures and specific heat of both the 7Mn and IF steels.…”

“…In the CT tests, the shim-out, no shim and shim-in setup corresponded to the peak loads of 7, 2, and 3 kN and the values of energy absorption as 56, 3, and 7 J, respectively; in this case, the shim-out welding set-up again produced the best mechanical properties but the no shim one was the worst. Moreover, the ductility ratio, which is defined as the ratio of the CT peak load to TS peak load and an indication of the joint ductility, [11] is shown in Figure 11(b). The comparison of ductility ratios among the three set-ups not only confirmed that the shim-out set-up indeed produced the best joint, but also suggested that the shim-in set-up should lead to the better joint ductility than the no shim one, which is consistent with the results of CT tests.…”

“…[10] However, we are still facing a great challenge in designing a proper weld process to obtain the good-quality welds with the satisfied properties for the medium-Mn TRIP steels because the brittle and hard phase is frequently formed during welding due to their high Mn content, which leads to a high susceptibility to cracking. [11] In the automotive industry, moreover, resistance spot welding (RSW) is a primary and vital sheet metal joining process due to the two advantages: the high welding speed and the excellent suitability for robotization. [12,13] There are about 3000 to 5000 spot welds in a typical steel body-in-white.…”

Nugget Formation and Characterization of Effect of Cover Plate on the Formation of Solidification Defects in Resistance Spot Welding of Dissimilar Al6016/HC420LA Steel

“…studied the liquid metal embrittlement–induced cracking of zinc‐coated twining‐induced plasticity steels during their RSW and developed an innovative pathway to obtain liquid metal embrittlement‐free welds. The weld discontinuities and defects that are likely to occur in the RSW of 1‐GPa transformation‐induced plasticity steel were also investigated by Ashiri et al . The results showed that the special thermophysical properties and rich chemistry of the alloy and complex thermomechanical processing have significant impacts on the susceptibility of the welds to defects, the amount of heat input induced by the welding process also plays an important role on defect formation.…”

“…To obtain reliable resistant spot welds joints, Ashiri et al [13,14] studied the liquid metal embrittlement-induced cracking of zinc-coated twining-induced plasticity steels during their RSW and developed an innovative pathway to obtain liquid metal embrittlement-free welds. The weld discontinuities and defects that are likely to occur in the RSW of 1-GPa transformation-induced plasticity steel were also investigated by Ashiri et al [15] The results showed that the DOI: 10.1002/adem.201901520…”