Detailed Microstructural Characterization and Restoration Mechanisms of Duplex and Superduplex Stainless Steel Friction-Stir-Welded Joints

2016 ◽  
Vol 25 (12) ◽  
pp. 5173-5188 ◽  
Author(s):  
T. F. A. Santos ◽  
E. A. Torres ◽  
J. C. Lippold ◽  
A. J. Ramirez
Keyword(s):  
Stainless Steel ◽  
Welded Joints ◽  
Microstructural Characterization ◽  
Friction Stir ◽  
Superduplex Stainless Steel

scholarly journals Development of High-Fidelity Imaging Procedures to Establish the Local Material Behavior in Friction Stir Welded Stainless Steel Joints

Metals ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 592
Author(s):  
S. Ramachandran ◽  
A. Lakshminarayanan ◽  
P. Reed ◽  
J. Dulieu-Barton
Keyword(s):  
Stainless Steel ◽  
High Resolution ◽  
Microstructural Characterization ◽  
Local Strain ◽  
Material Behavior ◽  
Image Correlation ◽  
Full Field ◽  
Friction Stir ◽  
2D Digital Image Correlation ◽  
304 Austenitic Stainless Steel

Friction stir welded (FSW) 304 austenitic stainless steel (SS) joints are studied using a range of microstructural characterization techniques to identify various sub-regions across the weld. A high-resolution (HR) 2D-digital image correlation (DIC) methodology is developed to assess the local strain response across the weld surface and cross-section in the elastic regime. The HR-DIC methodology includes the stitching of multiple images, as it is only possible to partially cover the FSW region using a single camera with the high-resolution optical set-up. An image processing procedure is described to stitch the strain maps as well as strain data sets that allow full-field strain to be visualized and interrogated over the entire FSW region. It is demonstrated that the strains derived from the DIC can be associated with the local weld geometry and the material microstructure in the region of the FSW. The procedure is validated in the material elastic range and provides an important first step in enabling detailed mechanical assessments of the local effects in the FSW process.

Effect of Cooling Rate on Mechanical and Microstructural Characterization of Friction Stir Welded 316 L Austenitic Stainless Steel Joints

2015 ◽  
Vol 830-831 ◽  
pp. 314-318 ◽  
Author(s):  
S. Shashi Kumar ◽  
N. Murugan ◽  
K.K. Ramachandran
Keyword(s):  
Stainless Steel ◽  
Microstructural Characterization ◽  
Secondary Phase ◽  
Weld Nugget ◽  
Friction Stir ◽  
316 L Stainless Steel ◽  
Gas Cooling ◽  
Aisi 316 ◽  
Steel Joints ◽  
Aisi 316 L

The present investigation is carried out to investigate on mechanical and metallurgical properties of Friction stir (FS) / Underwater Friction stir (UFS) welded 3 mm thick AISI 316 L stainless steel joints. Experiments were carried out at a tool rotational speed of 700 rpm, welding speed of 45 mm/min and axial force of 12 kN. Defect free joints were confirmed by visual inspection. A marginal rise of about 4.5 % increase in the joint strength is achieved in water cooling than by gas cooling technique. Reduced peak temperature in water cooled joint led to better grain refinement in the weld nugget enhancing FSW tool life. No sign of secondary phase precipitation was observed in the weld joints which was confirmed by Energy Dispersive Spectroscopy (EDS) spectrums and micro etchants like Groesbeck and modified Murakami reagents in the weld nugget.

Mechanical and Microstructural Characterization of Optimized Friction Stir Welded Twin Roll Cast AZ31B Sheets

2014 ◽  
Author(s):  
A. H. Ammouri ◽  
Haig Achdjian ◽  
A. Dorbane ◽  
G. Ayoub ◽  
G. T. Kridli ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Grain Growth ◽  
Welded Joints ◽  
Feed Rate ◽  
Microstructural Characterization ◽  
Major Axis ◽  
Friction Stir ◽  
Different Temperatures ◽  
Twin Roll Cast ◽  
Twin Roll

In order to select the optimum parameters for friction stir welding of twin-roll cast (TRC) AZ31B Mg-Al-Cu alloy, mechanical and microstructural characterizations are performed on friction stir welded 3 mm thick sheets under different processing parameters of rotational spindle speed and feed rate. Used was a tool made from high resistance Sverker 21 steel alloy with a 19 mm diameter cylindrical shoulder and a 6.4 mm diameter pin that extrudes 2.7 mm from the bottom of the shoulder. A large number of welded joints were prepared according to a test matrix of various combinations of rotational speed and feed rate. Tensile tests at different temperatures and strain rates were performed on specimens cut with their major axis perpendicular to the welded joints. Static strength tests of these specimens revealed that joints welded at a speed of 1200 rpm and a feed of 150 mm/min resulted in strengths as high as 94% of that of the as received TRC AZ31B metal. For specimens welded at spindle speeds larger than 1400 rpm, microstructural observations revealed the presence of micro cracks and voids located in the zone between the nugget and the thermally affected zone. In order to monitor the effect of lengthy testing times and the observed grain growth associated with slow strain tests, annealing tests under different temperatures and time durations were performed while monitoring grain diameter. Very limited grain growth have been obsereved after annealing and thus the mechanical performnace of the joints was solely due to the effect of the friction stir welding.

scholarly journals The Effect of Welding Conditions on Mechanical Properties of Superduplex Stainless Steel Welded Joints

2014 ◽  
Vol 14 (1) ◽  
pp. 14-23 ◽  
Author(s):  
A. Świerczyńska ◽  
J. Łabanowski ◽  
D. Fydrych
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Submerged Arc Welding ◽  
Flux Cored Arc Welding ◽  
Superduplex Stainless Steel ◽  
Zone Microstructure ◽  
Submerged Arc

ABSTRACT The tests results of superduplex stainless steel welded joints made with a different heat input, using automatic submerged arc welding (SAW) and semi-automatic flux-cored arc welding (FCAW) have been presented. Metallographic examinations, the measurements of the ferrite content, the width of the heat affected zone (HAZ) and the hardness of the welds in characteristic areas have been performed. Significant differences in the amount of ferrite in the weld metal and in the heat affected zone microstructure of joints were found.

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