Shielded metal arc welding of 9%Ni steel using matching ferritic filler metal

Abstract

Motivated by the tensile strength loss of 9%Ni steel arc welded joints made using Ni-based austenitic filler metals, the feasibility of maintaining the tensile strength using matching ferritic filler metal has been demonstrated. In comparison with shielded metal arc welded joint made using Ni-based austenitic electrode ENiCrMo-6, higher tensile strength comparable to that of the base metal was obtained using matching ferritic electrode. Besides, sufficient impact toughness energies with much lower mismatch were obtained for weld metal and heat-affected zone. Welded joint with a lower mechanical mismatching is of considerable importance for achieving acceptable combination of tensile strength and impact toughness. A better combination of these mechanical properties is ensured by applying a post weld heat treatment.

KEYWORDS:

• 9%Ni steel
• SMAW
• Ni-based austenitic welding electrode
• matching ferritic welding electrode
• microstructure
• mechanical properties
• mechanical mismatching

Acknowledgements

This work was supported by both the Science and Technology Development Fund (STDF) of Egypt under Grant GERF ID5111 and the Germany Aerospace Center (DLR) on behalf of the Federal Ministry of Education and Research (BMBF) of Germany under Grant 01DH14012. The authors would like to thank VoestalpineBöhler Welding, Germany GmbH for supplying the cost effective experimentally produced matching ferritic welding electrode. Appreciation is also extended to PETROJET-Egypt for carrying out the welding experiments on site.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by both the Science and Technology Development Fund (STDF) of Egypt under Grant GERF [ID5111] and the Germany Aerospace Center (DLR) on behalf of the Federal Ministry of Education and Research (BMBF) of Germany under Grant [01DH14012].