Laser welding of niobium to 410 steel with a nickel interlayer produced by electro spark deposition

•This research highlighted the possibility of using electrospark deposition process to place an interlayer for purpose of facilitation Nb to 410 stainless steel dissimilar laser welding•The electrospark interlayer had metallurgical bond with Nb, free of cracks with minimal dilution and have fine cellular structure with laves phase particles were observed with 30–50 nm in diameter.•The interlayer resulted in the reduction of the Nb concentration in the dissimilar laser weld zone to the level sufficient to suppress the formation of Fe-Nb intermetallic and enhance the weldability.•Tensile test of dissimilar laser weld made with the nickel base electrospark interlayer, exhibited an ultimate strength of about 285 MPa, and the failure was located in Nb and not in weld metal or the electrospark interlayer.

Some combination of metals such as niobium to stainless steel cannot be joined directly by laser welding due to formation of deleterious phases. On the other hand placement of a narrow strip of a third alloy between the two metals can introduce many technical and availability limitations. In this work, a more versatile method is developed using electrospark deposition (ESD) for facilitation of subsequent Nb to 410 stainless steel dissimilar laser with minimum heat input successfully. The 1 mm Nb plate edge was clad by Alloy 82 using a 4 mm round electrode by ESD process. The layer has minimum dilution with Nb while having a metallurgical bond. It exhibited a fine cellular structure with Laves phase particles with 30–50 nm in diameter. The Nb plate with edge built up was then laser welded to 410 stainless steel using a 1 KW fiber laser machine. The presence of the interlayer material suppressed the formation of NbFe intermetallic in the laser fusion zone and increases weldability. Tensile test of dissimilar laser weld with the nickel base ESD interlayer exhibited an ultimate strength of 285 MPa with the failure located at the Nb side and not in laser weld metal or at the ESD interface.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide