Influence of Vibration Stress Relief (VSR) on the Residual Stress and Microstructure in Welded Plate of DH36 Low Alloy High Strength Steel

2014 ◽  
Vol 887-888 ◽  
pp. 924-928 ◽  
Author(s):  
Shu Qi Li ◽  
Hong Yuan Fang ◽  
Xuesong Liu
Keyword(s):  
Residual Stress ◽  
High Strength Steel ◽  
High Strength ◽  
Stress Relief ◽  
Steel Plates ◽  
Widespread Application ◽  
Oil Platforms ◽  
Offshore Oil Platforms ◽  
Transmission Electron ◽  
Vibration Stress

Welded components of DH36 low alloy high strength steel are widely used in offshore oil platforms and ships building. Stress reliving treatments to these welded components is of great importance. Vibration stress relief (VSR) method is an novel technology to release stress in welded components. In this study, 10×200×1000mm DH 36 steel plates were welded and then treated by VSR for about 1 hour. After the treatment, the residual stress was decreased by 29-72% at the welded toe, where the highest residual stress occurs. The metallographic microstructure of the joint was not changed by VSR. Investigation by transmission electron microscope (TEM) revealed that the amount of dislocations was increased at the welded toe. We hope this study can provide theoretical and practical fundamentals for widespread application of VSR on welded offshore engineering components.

Numerical Simulation of Residual Stresses due to Multipass Welding in High Strength Steel Plates and Validation against Experimental Measurements

2018 ◽  
Vol 941 ◽  
pp. 269-273
Author(s):  
Constant Ramard ◽  
Denis Carron ◽  
Philippe Pilvin ◽  
Florent Bridier
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
High Strength Steel ◽  
High Strength ◽  
Steel Plates ◽  
Contour Method ◽  
Hole Drilling ◽  
Experimental Measurements ◽  
Element Analysis ◽  
Multipass Welding

Multipass arc welding is commonly used for thick plates assemblies in shipbuilding. Sever thermal cycles induced by the process generate inhomogeneous plastic deformation and residual stresses. Metallurgical transformations contribute at each pass to the residual stress evolution. Since residual stresses can be detrimental to the performance of the welded product, their estimation is essential and numerical modelling is useful to predict them. Finite element analysis of multipass welding of a high strength steel is achieved with a special emphasis on mechanical and metallurgical effects on residual stress. A welding mock-up was specially designed for experimental measurements of in-depth residual stresses using contour method and deep hole drilling and to provide a simplified case for simulation. The computed results are discussed through a comparison with experimental measurements.

Relationship between the Microstructure of the Welded Steel Plates and the Efficiency of Vibration Stress Relief

2014 ◽  
Vol 941-944 ◽  
pp. 2062-2065
Author(s):  
Shu Qi Li ◽  
Hong Yuan Fang ◽  
Xue Song Liu ◽  
Wei Cui
Keyword(s):  
Residual Stress ◽  
Stress Relief ◽  
Steel Plates ◽  
Low Alloy Steels ◽  
Welded Steel ◽  
Welded Structures ◽  
Vibration Stress ◽  
Alloy Steels ◽  
The Difference ◽  
Main Factor

Welded components of low alloy steels are widely used in various applications. Stress reliving is very important to these welded structures. Vibration stress relief (VSR) is an relatively new method for this purpose. In this study, Q235 and Q345 steel plates were welded. Then they were treated by VSR. The microstructure of the welded lines were investigated and the residual stresses in two directions in these welded structures were measured. The difference of the efficiency of VSR on the two materials were investigate. It is found that, the decreasing amplitude of the residual stress in the Q235 welded structures significantly exceeded that in the Q345 welded structures. The grain size in the area near the weld lines is the main factor that affects the efficiency of the VSR treatment.

scholarly journals Residual stress distributions in laser and gas-metal-arc welded high-strength steel plates

2016 ◽  
Vol 32 (14) ◽  
pp. 1449-1461 ◽  
Author(s):  
W. Guo ◽  
J. A. Francis ◽  
L. Li ◽  
A. N. Vasileiou ◽  
D. Crowther ◽  
...  
Keyword(s):  
Residual Stress ◽  
High Strength Steel ◽  
High Strength ◽  
Steel Plates ◽  
Stress Distributions

Thermal Vibration Compound Stress Relief on Thick DH36 Steel Welded Plates

2014 ◽  
Vol 576 ◽  
pp. 143-147 ◽  
Author(s):  
Shu Qi Li ◽  
Hong Yuan Fang ◽  
Xue Song Liu ◽  
Wei Cui
Keyword(s):  
Weld Line ◽  
Stress Relief ◽  
Thermal Vibration ◽  
Oil Platforms ◽  
Additional Heating ◽  
Offshore Oil Platforms ◽  
Before And After ◽  
Vibration Stress ◽  
Transverse Stresses ◽  
Offshore Oil

Stress relief on thick and large welded components is greatly needed in various applications, such as large oil transporting pipes and offshore oil platforms. Vibration stress relief (VSR) is an relatively new method for this purpose. The efficiency of this method is a key subject, especially when the components are extremely large and it is difficult to trigger sufficient vibration amplitude in the structures. In this study, additional heating on the area near the weld line was used to promote the efficiency of VSR. Both VSR and thermal-vibration compound stress relief (TVCSR) were used to 50mm thick DH 36 steel welded plates. The Longitudinal and transverse stresses near the weld lines before and after the treatments were investigated. Comparing to VSR, the TVCSR was more effective in decreasing the residual stress. Effects of additional heating was discussed.

Capability of martensitic low transformation temperature welding consumables for increasing the fatigue strength of high strength steel joints

2020 ◽  
Vol 62 (9) ◽  
pp. 891-900
Author(s):  
Jonas Hensel ◽  
Arne Kromm ◽  
Thomas Nitschke-Pagel ◽  
Jonny Dixneit ◽  
Klaus Dilger
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Fatigue Strength ◽  
High Strength Steel ◽  
Transformation Temperature ◽  
Fatigue Cracks ◽  
High Strength ◽  
Filler Material ◽  
Phase Transformation Temperature ◽  
Filler Materials

Abstract The use of low transformation temperature (LTT) filler materials represents a smart approach for increasing the fatigue strength of welded high strength steel structures apart from the usual procedures of post weld treatment. The main mechanism is based on the effect of the low start temperature of martensite formation on the stress already present during welding. Thus, compressive residual stress formed due to constrained volume expansion in connection with phase transformation become highly effective. Furthermore, the weld metal has a high hardness that can delay the formation of fatigue cracks but also leads to low toughness. Fundamental investigations on the weldability of an LTT filler material are presented in this work, including the characterization of the weld microstructure, its hardness, phase transformation temperature and mechanical properties. Special attention was applied to avoid imperfections in order to ensure a high weld quality for subsequent fatigue testing. Fatigue tests were conducted on the welded joints of the base materials S355J2 and S960QL using conventional filler materials as a comparison to the LTT filler. Butt joints were used with a variation in the weld type (DY-weld and V-weld). In addition, a component-like specimen (longitudinal stiffener) was investigated where the LTT filler material was applied as an additional layer. The joints were characterized with respect to residual stress, its stability during cyclic loading and microstructure. The results show that the application of LTT consumables leads to a significant increase in fatigue strength when basic design guidelines are followed. This enables a benefit from the lightweight design potential of high-strength steel grades.

scholarly journals Enhancement of Road Freight Vehicle Fuel Efficiency Using Lightweight Flat-Bed Trailers Made of High-Strength Steel Plates

2015 ◽  
Vol 22 (2) ◽  
pp. 65-82 ◽  
Author(s):  
Hong-Seung Roh ◽  
민연주 ◽  
장소영 ◽  
신승진 ◽  
YU, Byeong-Jae ◽  
...  
Keyword(s):  
High Strength Steel ◽  
Fuel Efficiency ◽  
High Strength ◽  
Steel Plates ◽  
Road Freight ◽  
Vehicle Fuel Efficiency
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