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Metallurgical Characterization and Weldability Evaluation of Ferritic and Austenitic Welds in Armor Steels

Armored steels are used in construction of military vehicles, which require properties such as high strength and high toughness to withstand blast and impact situations.  Currently, these armored steels are welded using low-alloy consumables; however, welding with these consumables can lead to hydrogen-induced cracking (HIC) under certain conditions.  Welding steels with austenitic stainless steel filler metals has shown to mitigate the susceptibility to HIC.  While the use of austenitic stainless steel filler metals for welding armored steels may reduce HIC susceptibility, other weldability challenges may arise, such as susceptibility to solidification cracking and/or reduced strength characteristics.  This project investigates the microstructure, solidification cracking susceptibility, and HIC susceptibility of welds between armored steels (Armox 440 and RHA) with Sandvik AXT (~ER307), ER309LHF, and ER312 stainless steel filler metals.  The goal is to determine which stainless steel consumable(s) is the most suitable for welding of each armored steel in single and multi-pass weldments. 

 

Metallurgical characterization and computational modeling was performed in order to study the microstructure and solidification process in each dissimilar metal weld. The Tekken Test and CTS Test was performed to analyze the susceptibility to HIC.  Tests were also conducted using low-alloy steel consumables (ER100 and ER70S-6) as a comparison. It was found that HIC is only an issue in welds made with low-alloy consumables. Welds made with stainless steel consumables only experienced solidification cracking if cracking occurred. 

 

 

Industry Sponsor: American Engineering and Manufacturing

Faculty: Boian Alexandrov (OSU)

Graduate Student: Matthew Duffey

Industry Contact: John Lawmon