| The Effect of TiO2 incorporation on the microstructural and mechanical properties of friction stir welded API 70 steel |
| Paper ID : 1586-UFGNSM-FULL |
| Authors: |
|
Rasoul Pouriamanesh *1, kamran dehghani2, Rudolf Vallant3, Norbert Enzinger3 1Azadi Ave. (site 1), Mahshahr Petrochemical Special Economic Zone, Mahshahr, Khuzestan, Iran 2Amirkabir University of Technology 3Institute of Materials Joining and Forming, Graz University of Technology, Graz, Austria |
| Abstract: |
| In this paper, the microstructure and hardness properties of friction stir welding (FSW) of TiO2 /API X70 was studied. TiO2-free and TiO2-doped samples were FSW processed by one pass at rotational speed of 600 rpm and 30 mm/min travel speed. In case of doping particles, regions of particle-rich and particle-free is developed in stir zone. Microhardness was measured to evaluate the mechanical properties of the stir zone. The microstructure of the different zones was studied by optical microscopy. Results show that the incorporated particles inside the stir zone with a sub-micron size affect the microstructure which is quite different from the TiO2-free sample. Different ferrite morphologies developed in stir zone for both samples. The hardness of various zones in the weld are strongly depended on the microstructure. In particular, in particle-free sample the hardness is 190 HV with a microstructure of some large polygonal ferrite, ferrite side plate and bainite. On the other side in composite sample a transition from an acicular ferrite (AF) dominant microstructure with a hardness value of 300 HV to a polygonal ferrite (PF) dominant microstructure with a hardness value of 180 HV was observed by moving from top surface region to near root region. |
| Keywords: |
| TiO2, Friction Stir Welding (FSW), acicular ferrite, refinement, HSLA steel, composite |
| Status : Paper Accepted (Poster Presentation) |
