Method for determination of ferrite number in austenitic weld metal deposited by covered Cr-Ni steel electrodes

AbstractNowadays, ultra-high hard armor (UHA) steels are employed in armor tracked vehicle (ATV) construction because of their high hardness, high strength to weight ratio, and excellent toughness. UHA steels are usually welded using austenitic stainless steel (ASS) welding consumables, to avoid hydrogen-induced cracking (HIC). The use of ASS consumables to weld the above steel was the only available remedy because of higher solubility of hydrogen in the austenitic phase. In this investigation, an attempt was made to investigate the effect of ASS consumables (with different Creq/Nieq ratio) on solidification mode, impact toughness and microstructural characteristics of shielded metal arc (SMA) welded UHA steel joints. The welded joints were characterised based on impact toughness properties, hardness, and microstructural features. As the ferrite number increases with an increase in Creq/Nieq ratio result in different solidification mode (A, FA, F). It is also found that ferrite number of weld metal has appreciable influence on impact toughness and has inversely proportional relationship with impact toughness of the welded joints.

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Determination of the main characteristics of the temperature field for the evaluation of the type of solidification of weld metal in fusion welding

Welding International ◽

10.1080/09507110701637932 ◽

2007 ◽

Vol 21 (8) ◽

pp. 600-604 ◽

Cited By ~ 5

Author(s):

P. Rayamyaki ◽

V.A. Karkhin ◽

P.N. Khomich

Keyword(s):

Temperature Field ◽

Weld Metal ◽

Fusion Welding

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Review of Ferrite Number (FN) Requirements and Proposed Changes to Code Case N-504-4 and Nonmandatory Appendix Q

Volume 1: Codes and Standards ◽

10.1115/pvp2019-93637 ◽

2019 ◽

Author(s):

Steven L. McCracken ◽

David Segletes

Keyword(s):

Stainless Steel ◽

Weld Metal ◽

Carbon Content ◽

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Nuclear Power ◽

Nuclear Regulatory Commission ◽

Corrosion Cracking ◽

Delta Ferrite ◽

Ferrite Number

Abstract ASME Section XI Nonmandatory Appendix Q and Code Case N-504-4 are routinely used to install full structural weld overlays in the nuclear power industry for repair or mitigation of stress corrosion cracking in austenitic stainless steel weldments. Both Appendix Q and N-504-4 specify a Ferrite Number (FN) and carbon content requirement for the stainless steel weld metal used for the weld overlay to ensure acceptable resistance to stress corrosion cracking. The Ferrite Number (FN) is used in the ASME Code for establishing the delta ferrite content in the deposited weld metal. Field experience indicates there is often confusion and differing opinion concerning how the Ferrite Number and carbon content requirements of Appendix Q and N-504-4 are satisfied. This is in part due to unavailability of the original technical basis for these requirements. This paper provides a background for the delta ferrite and carbon content requirements, information on influence of delta ferrite and carbon content on stress corrosion cracking and U.S. Nuclear Regulatory Commission (NRC) guidance on the issue. Finally, this paper details a proposed revision of Nonmandatory Appendix Q and N-504-4 to clarify the FN and carbon content requirements.

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