| Investigation of FSW on microstructural characterization and mechanical properties of Nano-TiO2 doped API-X70 steel |
| Paper ID : 1021-UFGNSM-FULL |
| Authors: |
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NADER MASTOORI1, kamran dehghani2, Nader Mastoori *3 1tehran 2Amirkabir University of Technology 3Amirkabir university of technology |
| Abstract: |
| The Joining process of HSLA steels by traditional arc welding methods adversely affect the refined microstructure leading to reduced material performance. Conversely, Friction Stir Welding (FSW) is a solid-state joining process, meaning no melting occurs during the process. By the way, in current research study the effect of Friction Stir Welding (FSW) on microstructure and mechanical properties of API-X70 high-strength alloy steel was investigated. FSW process was applied to incorporate the TiO2 nano-powder to form a surface composite structure in the nugget zone. The effect of various operational FSW parameters on microstructural evolution of stir zone was investigated, and tensile performances of samples were examined in constant traverse speed of 32 mm/min, as functions of different rotational speeds (400, 600 and 1000 rpm). Micro-hardness test was performed for characterization of mechanical mechanical properties. The microstructure of the different zones (weld nugget - thermo-mechanically affected zone and head affected zone) was studied by optical and scanning electron microscopy. TiO2-doping leads to grain refinement (mixture of ferrite and AF) and lead to formation of a combination fine ferrite grains and acicular ferrite which has better mechanical performance. The obtained results showed that the finer structure of AF formed by addition of nano-TiO2, and the mechanical properties was increased. |
| Keywords: |
| Keywords: Friction Stir Welding (FSW), HSLA X70, rotational speeds, TiO2nano-powder. |
| Status : Paper Accepted (Poster Presentation) |
