International Journal of Iron & Steel Society of Iran

International Journal of Iron & Steel Society of Iran

Evaluation of Mechanical Properties of Welding ST-37 Steel Structures With Two Types of Welding Processes FCAW and SMAW

Document Type : Research Paper

Authors
1 Mechanical Engineering, Payame Noor University, Tehran, Iran
2 Department of Mechanical Engineering,, Technical and vocational university Tehran, Iran.
3 Department of Structural Engineering, Bandar Abbas Branch, Islamic Azad University, Bandar Abbas, Iran
Abstract
 ST-37 steel is applied in the construction of steel structures due to its good strength, toughness, and high weldability. In this study, two samples of ST-37 steel joint were prepared using E71T filler metal by FCAW powder coating process and E7018 electrode by SMAW method. Tensile strength, hardness, and impact resistance of the weld were examined. The results showed that the final weld strength of both welding methods was higher than 400MPa so that therefore the tensile sample from the base metal of ST-37 failed. The final strength values obtained in the FCAW welded samples were higher than in the SMAW welded samples. Hardness test results showed that the hardness of the heat-affected area increased compared to ST-37 steel in both welding methods. The mean weld metal hardness was (207) SMAW and (184) FCAW Vickers. Vickers hardness values for the base metal and the heat-affected zone also showed the same behavior as the weld metal in the two samples. The hardness average values of HAZ on both sides of the weld joint were higher than the base metal. The impact test results showed that the average impact energy of weld metal (SMAW 86J) is higher than the average impact energy of weld metal (FCAW 81J). Therefore, FCAW and Filler E71T meet the requirements of final strength and weld resistance by the seismic criteria of AISC Regulation 341-10 and also the tenth article of the National Building Regulations of Iran. 
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