Journal of Science and Technology of Composites

Journal of Science and Technology of Composites

Studying influence of adding carbon and boron amount on microstructure and hardness of iron – based hardfacing layer using Flux Cored Arc Welding

Document Type : Research Paper

Authors
mohammadreza tavakoli shoushtari 1
Massoud goodarzi 1
hamed sabet 2
1 School of Metallurgy and Materials Engineering, Iran University of Science & Technology, Tehran, Iran
2 Department of Materials Engineering, Karaj Branch, Islamic Azad University, Karaj, Iran
10.22068/jstc.2018.70942.1365
Abstract
In present investigation, hard claddings treatment was performed on st37 steel using two cored electrodes containing Fe-B and Fe-B-C powder-based by FCAW (Flux Cored Arc Welding) method during three stages of single pass, two-pass and three-pass welding process. Results indicated that the increasing of welding pass numbers for both welding electrode, boron percentage was improved from 2.3 to 3.18 wt. % at weld metal due to more presence of boron in liquid phase which caused volume increase of electrode at each welding pass. Microstructure observation results also expressed that the using of Fe-B electrode for single pass welding process caused to create a ferrite matrix and α-Fe2B eutectic; for two-pass welding process compared to single pass ferrite islands have been decreased, while the amount of α-Fe2B eutectic have been increased. Third pass of welding process caused to form α-Fe2B eutectic and primary particles of Fe2B which had columnar shape. Presence of carbon in Fe-B-C electrode will form pearlite islands beside primary Fe2B. Also, at third pass of welding process by both electrodes, very low amount of FeB phase would be formed around the Fe2B primary phase. Formation of FeB compound related to segregation of boron element during welding and non-equilibrium solidification. The increase in hardness can also be attributed to an increase in the amount of boron due to the increasing number of welding passes.
Keywords
flux-cored Arc welding
hardfacing
Fe-B
Microstructure
welding passes

Subjects

 
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Journal of Science and Technology of Composites
Volume 5, Issue 2
Summer 2018
Pages 245-252