Microstructural analysis of friction stir welded ferritic stainless steel

Cho, Hoon-Hwe; Han, Heung Nam; Hong, Sung-Tae; Park, Jong‐Hwan; Kwon, Youngmee; Kim, Seok-Hyun; Steel, Russell

doi:10.1016/j.msea.2010.12.061

Cited by 101 publications

(33 citation statements)

References 20 publications

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“…Generally, the studies on microstructural evolution during FSW of ferrous metals, having both face-centred cubic (FCC) and body-centred cubic (BCC) crystal structures, are mainly on materials in which solid state phase transformation does not occur during the process. For example the investigations on the microstructure evolution during FSW of pure iron [21], type 409 ferritic stainless steel [22] and the recrystallisation behaviour of type 304L stainless steel [5].…”

Section: Introductionmentioning

confidence: 99%

Development of Microstructure and Crystallographic Texture in a Double-Sided Friction Stir Welded Microalloyed Steel

Rahimi

Wynne

Baker

2016

Metall Mater Trans A

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The evolution of microstructure and crystallographic texture has been investigated in double-sided friction stir welded microalloyed steel, using electron backscatter diffraction (EBSD). The microstructure analyses show that the centre of stirred zone reached a temperature between Ac 1 -Ac 3 during FSW, resulting in a dual phase austenitic/ ferritic microstructure. The temperatures in the thermo-mechanically affected zone and the overlapped area between the first and second weld pass did not exceed the Ac 1 . The shear generated by the rotation probe occurs in austenitic/ferritic phase field where the austenite portion of the microstructure is transformed to a bainitic ferrite, on cooling. Analysis of crystallographic textures with regard to shear flow lines generated by the probe tool, show the dominance of simple shear components across the whole weld. The austenite texture at Ac 1 -Ac 3 is dominated by the B and simple shear texture components, where the bainite phase textures formed on cooling were inherited from the shear textures of the austenite phase with relatively strong variant selection. The ferrite portion of the stirred zone and the ferrites in the thermo-mechanically affected zones and the overlapped area underwent shear deformation with textures dominated by the D 1 and D 2 simple shear texture components. The formation of ultra-fine equiaxed ferrite with submicron grain size has been observed in the overlapped area between the first and second weld pass. This is due to continuous dynamic strain-induced recrystallisation as a result of simultaneous severe shear deformation and drastic undercooling.

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Section: Introductionmentioning

confidence: 99%

Development of Microstructure and Crystallographic Texture in a Double-Sided Friction Stir Welded Microalloyed Steel

Rahimi

Wynne

Baker

2016

Metall Mater Trans A

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“…Friction stir welding of 409 ferritic stainless steel welded by Polycrystalline Cubic Boron Nitride (PCBN) tool was studied by Cho et al [21] and found that fine grain microstructure was resulted by dynamic recrystallization. The microstructure and mechanical properties of friction stir welded 409L stainless steel were investigated by Ahn and et al [22] and found that the mechanical properties in the weld were similar to that of the base material (BM).…”

Section: Ferritic Stainless Steel:-mentioning

confidence: 99%

Friction Stir Welding of Stainless Steels – Review.

Rajasekhar¹

2016

IJAR

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After development of tungsten alloys and polycrystalline cubic boron nitride (PCBN) tools, lot of progress is made in FSW of stainless steel. Although some issues remain to be solved, satisfactory welds are produced and weld properties are found suitable for the intended applications. This paper summarizes the progress of research work on Friction stir welding of different types of stainless steels. It covers the research made in the selection of suitable tool materials, optimizing the process parameters such as tool travel speed, rotational speed, tilt angle etc. The influence of Friction stir welding on microstructure and mechanical properties of welds has also been reviewed. Fusion welding involves use of filler materials, shielding gases, and development of high energy density which results wider heat affected zone. The weldments show appreciable modification in the microstructure and properties of weld and heat affected zones, which may result solidification defects like distortion, , lack of penetration, poor fusion, cracks etc. Use of plasma arc and laser beam welding techniques can produce sound welds of thicker materials with narrow heat affected zone [2], however these techniques are not suitable for certain materials such as aluminium, magnesium etc.The drawbacks in the fusion welding techniques can some extent addressed by solid state welding techniques (e.g. resistance welding, friction welding) in which welding takes place at a temperature lower than the melting point of base metals and also no filler material and / or shielding gases are required. In resistance welding coalescence occurs due to heat generated by contact resistance and applied pressure and hence, it is not suitable for materials having high electrical conductivity (e.g. aluminium, copper). Friction welding employs frictional heat generated when a moving workpiece and a fixed component are forced together in order to obtain the required heat and temperature for weld. However, the application of friction welding is limited by the geometry of the workpieces to be joined.The above difficulties can successfully overcome by friction stir welding (FSW), a solid state welding process which was developed by the welding institute (TWI) [3] primarily for welding of aluminium and magnesium based alloys. The major advantages of FSW over other welding processes are lower distortion, good dimensional stability, absence of cracking etc.

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“…Recent researches reveal that friction stir welding (FSW) method can compensate for the shortcomings of the conventional processes. However, a clear understanding of the effect of processing parameters in ferrous alloys has been a matter of conjecture [11,[12][13].…”

Section: Introductionmentioning

confidence: 99%

“…Cho et al [12] joined 409 stainless steel specimens and reported that severe plastic deformation led to the generation of fine grains, low angle grain boundaries, and high hardness in the weld metal. In another research Sato [14] found that the grain size of the stir zone of SAF 2507 was smaller than that of the base metal.…”

Section: Introductionmentioning

confidence: 99%

Microstructural evolution in friction stir welded API 5L-X52 steel

Gharibshahiyan¹,

Honarbakhsh-Raouf²,

Parvin³

2015

International Advanced Research Journal in Science, Engineering

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Welded API-5L steel pipes have been extensively used in the oil industry. One of the major parameters affecting the mechanical properties is the grain size, which is altered with the joining method. In this paper microstructural evolution in the friction stir welded API 5L-X52 steel pipes has been investigated.Specimens were cut from a 2mm thick API 5L-X52 steel pipe. The steel sheets were then joined by friction stir welding process; at a linear speed of 100 mm/min. The tool rotational speed was varied from 400 to 800 rpm. Samples were then evaluated using tensile test, metallographic and hardness measurements. Microstructural investigations revealed the stir zone, heat affected zone and thermo mechanically affected zones. Heat input in the stir zone led to the formation of elongated austenite grains which were transformed to fine ferrite and pearlite grains and widmanstatten ferrite in certain regions. Plastic deformation and recrystallization enhanced the hardness and tensile strength as well as toughness of the welded joint in the API 5L-X52 steel.

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Microstructural analysis of friction stir welded ferritic stainless steel

Cited by 101 publications

References 20 publications

Development of Microstructure and Crystallographic Texture in a Double-Sided Friction Stir Welded Microalloyed Steel

Development of Microstructure and Crystallographic Texture in a Double-Sided Friction Stir Welded Microalloyed Steel

Friction Stir Welding of Stainless Steels – Review.

Microstructural evolution in friction stir welded API 5L-X52 steel

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