The Effect of Heat Treatment on the HAZ Microhardness and Fracture Resistance of Weld Joints of ABS EH36 150-mm Heavy Plates for Monopiles of Offshore Wind Generators

2019 ◽  
Author(s):  
E. Goli-Oglu ◽  
Z. Greisen
Keyword(s):  
Heat Treatment ◽  
Fracture Resistance ◽  
Offshore Wind ◽  
Weld Joints ◽  
Wind Generators

scholarly journals Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4366
Author(s):  
Saqib Anwar ◽  
Ateekh Ur Rehman ◽  
Yusuf Usmani ◽  
Ali M. Al-Samhan
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Grain Size ◽  
Heat Affected Zone ◽  
Tensile Testing ◽  
Weld Zone ◽  
Alloy 800H ◽  
Weld Joints ◽  
Heat Treated ◽  
Friction Weld

This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

Influence of heat treatment on the tensile and hardness characteristics of friction stir weld joints of dissimilar aluminium alloys

2022 ◽  
Author(s):  
K. Ramesha ◽  
P. D. Sudersanan ◽  
Prem Kumar Mahto ◽  
Shaikh Mohammed Ismail ◽  
Ashwin C. Gowda ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Aluminium Alloys ◽  
Friction Stir Weld ◽  
Friction Stir ◽  
Weld Joints

scholarly journals Heat treatment mode optimization of dissimilar weld joints of EP517 steel to 36NKhTYu alloy

2020 ◽  
Vol 759 ◽  
pp. 012024
Author(s):  
E V Terentyev ◽  
A Yu Marchenkov ◽  
A L Goncharov ◽  
A P Sliva ◽  
K T Borodavkina
Keyword(s):  
Heat Treatment ◽  
Treatment Mode ◽  
Dissimilar Weld ◽  
Weld Joints ◽  
Heat Treatment Mode ◽  
36Nkhtyu Alloy

Increase of Weld Joint Efficiency of the Combined Band of a High-Speed Rotor of an Electric Machine by Local Strengthening

2020 ◽  
Vol 299 ◽  
pp. 370-375
Author(s):  
Egor V. Terentyev ◽  
Artem Yu. Marchenkov ◽  
Andrey P. Sliva
Keyword(s):  
Heat Treatment ◽  
Tensile Stress ◽  
Weld Metal ◽  
High Speed ◽  
Electron Beam Welding ◽  
Ultimate Tensile Stress ◽  
Electric Machine ◽  
Weld Width ◽  
Weld Joints ◽  
36Nkhtyu Alloy

The research shows the possibility of increasing the structural strength of the weld joints of EP517 steel and 36NKhTYu iron-nickel alloy as applied to the combined bandage of the high-speed rotor of an electric machine, due to the effect of local strengthening of the soft interlayer. The technology of electron-beam welding of 36NKhTYu alloy to EP517 steel with free root formation, which allows to obtain narrow welds, is described. The results of metallographic researches and mechanical tests of weld joints with different weld widths are presented, which showed that the structure and properties of the weld metal on samples with different weld widths are almost identical. The tension test results of weld joints demonstrate a significantly greater ultimate tensile stress, compared to the ultimate tensile stress of the weld metal. Also, it was established that, due to the local strengthening phenomena the smaller the weld width, the stronger the welded joint is. In addition, the use of heat treatment after welding allows us to increase the strength properties of the weld metal and the heat-affected zone of the 36NKhTYu alloy, due to the formation of the hardening γ’-phase. The possibility of increasing the ultimate tensile strength of the weld up to 98% of the ultimate tensile stress value of EP517 steel (as the less durable of both welded materials), due to heat treatment and reducing the weld width, is demonstrated.

scholarly journals Parameter Estimation of Chopper Resistor in Medium-Voltage-Direct-Current during Grid Fault Ride through

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3480 ◽  
Author(s):  
Hyeong-Jin Lee ◽  
Jin-Su Kim ◽  
Jae-Chul Kim
Keyword(s):  
Parameter Estimation ◽  
Wind Farms ◽  
Offshore Wind ◽  
System Capacity ◽  
Offshore Wind Farms ◽  
Voltage Rise ◽  
Dc Voltage ◽  
Medium Voltage ◽  
Wind Generators ◽  
Fault Ride Through

Offshore wind farms with good wind quality are exponentially increasing. To take advantage of this, the offshore wind farms and the grid are connected using the MVDC. In the event of a grid fault, the traditional wind generators and the MVDC are disconnected from the grid fault to protect the devices. However, the wind generators and the MVDC must support the recovery of the grid fault because the disconnection of large capacity wind farms will cause a grid collapse. To prevent this problem, the LVRT requires maintaining the connection between the wind generators and the grid to contribute to the recovery of the grid fault. In this situation, the DC voltage of the MVDC rises due to the unbalanced power of the input and output. Several methods have been proposed to suppress the DC voltage rise of the MVDC. Among various methods, the CR is an effective method to suppress the DC voltage rise of the wind generators and the MVDC. However, the conventional CR designs only consider rated voltage and system capacity. Therefore, this paper proposes the parameter estimation of the CR considering the important factors. The proposed method is verified by PSCAD/EMTDC.

Post-weld Heat Treatment and Groove Angles Affect the Mechanical Properties of T92/Super 304H Dissimilar Steel Weld Joints

2018 ◽  
Vol 37 (7) ◽  
pp. 649-654 ◽  
Author(s):  
Wang Shuo ◽  
Wei Limin ◽  
Cheng Yi ◽  
Tan Shuping
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Weld Metal ◽  
Arc Welding ◽  
Post Weld Heat Treatment ◽  
Steel Weld ◽  
Dissimilar Weld ◽  
Weld Joints ◽  
Gas Tungsten Arc ◽  
Weld Heat

AbstractThe microstructures and mechanical properties of dissimilar weld joints between T92 and Super 304H steels were investigated. Dissimilar weld joints with four groove angles were constructed using gas tungsten arc welding. The results showed that post-weld heat treatment improved the mechanical properties of the dissimilar weld joints. The optimal groove angle for T92/Super 304H dissimilar weld joints was found to be 20°, considering mechanical properties. Furthermore, the transformation from equiaxed dendrites to columnar dendrites was observed in the weld metal. Epitaxial growth and delta ferrites were found around the fusion line between the Super 304H and the weld metal.

Sign in / Sign up

Export Citation Format

Share Document