A B C D E F G H I J K L M N O P Q R S T U V W X Y Z All
Parida, S.
- Microstructure Evolution and Mechanical Properties of Friction Stir Welded Thick HSLA Steel
Authors
1 Naval Metallurgy Division, Naval Materials Research Laboratory, Ambernath, Thane - 421 506, Maharashtra, IN
Source
Indian Welding Journal, Vol 51, No 3 (2018), Pagination: 54-58Abstract
Friction stir welding (FSW) is known for joining low softening alloys metals such as aluminum, magnesium and copper, however joining of high softening alloys like steel, titanium and nickel base alloys is still a challenge due to tool material stringent property requirements and its availability. Presently, due to development new generation tool material FSW of high softening alloys is possible and also reported. FSW can effectively join different grade of low thickness steel, however the questions about joining thick section steel still remains a challenge.
In this paper, FSW of 7 mm, 12 mm and 24 mm thick HSLA steel in single and double pass was carried out to develop the processing window for defect free weld joints and understanding the structure-property correlation. The increase in thickness of the base metal resulted in generation of higher load, higher heat input and consequently lower cooling rate. Therefore, the microstructure obtained after FSW in different thickness of steel also shows varying microstructures (grain boundary ferrite, acicular ferrite, widmensttan ferrite and upper bainite). Optical and scanning electron microscope (SEM) with electron back scattered diffraction (EBSD) detector was utilized to characterize the microstructure of FSW nugget zone. Tensile and hardness properties were also evaluated and correlated with the microstructure.
Keywords
Friction Stir Welding, High Strength Low Alloy Steel (HSLA), Microstructure, Tensile Properties, Scanning Electron Microscopy.
References
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- Thermal Assisted Friction Stir Welding of HSLA Steel:A Novel Approach to Mitigate Lower Toughness and Ductility
Authors
1 Naval Metallurgy Division, Naval Materials Research Laboratory, Ambernath, Thane-421506, Maharasthra, IN
2 Defence Institute of Advanced Technology, Girinagar, Pune-411205, IN
Source
Indian Welding Journal, Vol 52, No 4 (2019), Pagination: 46-52Abstract
Friction stir welding (FSW) technology is well-known forits capability to join low softening metals and alloys such as aluminum and magnesium, conversely, high softening alloys like steel, titanium and nickel alloys is still a challenge due to tool material stringent property requirements and its availability. Presently, with the advancement in the development of tool materials,the joining of high softening alloysis possible. However, in case of high strength quench sensitive grade of steel, high cooling rate associated during FSW induces undesirable brittle martensitic microstructure and therefore, reduces the properties of the weld zone, particularly, the ductility and toughness. Therefore, in present investigation a novel approach to control the microstructure was investigated by employing induction pre heating source ahead of tool pin during FSW. The HSLA plate preheated at 300 °C and 600 °C respectively resulted in simultaneous increase of ductility and toughness because of widmanstätten ferrite and bainitic microstructure due to lower cooling rate. In case of FSW carried out without preheating the hard brittle zone was found, whereas the same was eliminated with preheating source. Optical and scanning electron microscope (SEM) with electron back scattered diffraction (EBSD) detector was utilized to characterize the microstructure of FSW nugget zone, and was correlated with mechanical properties.Keywords
Thermal Assisted Friction Stir Welding, High Strength Low Alloy Steel (HSLA), Microstructure, Mechanical Properties, Scanning Electron Microscopy.References
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