Effect of ERNiCr-3 and ER70S-G Filler Metals on Mechanical and Microstructural Properties of TIG-Welded SS 409–Cu C11000 Joints

Abstract:

Welding ferritic stainless steel to copper is well known to be challenging because of the large mismatch in their thermal conductivities and metallurgical behaviors. Dissimilar joints are required in a range of energy, automotive, and metallurgical applications. In this study, TIG welding of SS 409 to copper C11000 was performed using ERNiCr-3 (Ni-based) and ER70S-G (Mn-based) filler metals under controlled DCEN conditions to evaluate their mechanical and microstructural performance. Tensile testing, microhardness mapping, and microstructural observations using scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDS) were performed after the welding process. The results show that the joints welded with ERNiCr-3 exhibited a higher ultimate tensile strength, reaching approximately 220 MPa, along with an elongation of approximately 10%. In comparison, ER70S-G joints achieved a tensile strength of approximately 160 MPa and exhibited lower ductility, with an elongation of approximately 6%. A smoother hardness transition across the weld interface was observed for ERNiCr-3, whereas ER70S-G produced a more localized hardness peak close to the fusion boundary. SEM-EDS analysis indicated sound fusion for both filler metals, with limited formation of interfacial compounds. Based on these results, ERNiCr-3 remains the preferred filler when a higher mechanical performance is required. However, ER70S-G can be considered a practical and economical alternative to TIG-welded SS 409–Cu C11000 joints in applications where moderate strength is sufficient.

• Periodical: Materials Science Forum (Volume 1195)
• Pages: 33-39
• DOI: https://doi.org/10.4028/p-FJ9xR1
• Online since: June 2026
• Authors: Yusuf Eko Nurcahyo, Yudy Surya Irawan*, Oyong Novareza, Sugiarto Sugiarto
• Keywords: Copper C11000, Dissimilar Welding, ER70S-G, ERNiCr-3, Ferritic Stainless Steel, TIG Welding

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