Residual Stress Analysis and Weld Bead Shape Study in Laser Welding of High Strength Steel

2013 ◽  
Author(s):  
Wei Liu ◽  
Fanrong Kong ◽  
Radovan Kovacevic
Keyword(s):  
Heat Treatment ◽  
Residual Stress ◽  
Laser Welding ◽  
Welding Speed ◽  
High Strength Steel ◽  
Laser Power ◽  
Measurement Data ◽  
Welding Process ◽  
High Strength ◽  
Weld Bead

The X-ray diffraction (XRD) technique is employed to measure residual stress induced by the laser welding of 6.7 mm thick ASTM A514 high strength steel plates. The distribution of residual stress in the weld bead is investigated. The results indicate that the fusion zone (FZ) has the maximum tensile stress, the transition from tensile to compressive stress tends to appear in the heat affected zone (HAZ), and the initial stress far from the weld center are not influenced by the welding process. Based on the measurement data, the influence of the laser power and the welding speed on residual stress is obtained. The magnitude of residual stress near the weld bead increases with an increase in laser power or a decrease in welding speed. The welds with incomplete penetration have a considerably lower magnitude of residual stress in FZ than ones with full penetration. Post-weld heat treatment is utilized to relieve residual stress in the weld bead. Although residual stress is not completely relieved after the heat treatment, a dramatically reduced magnitude and much more uniform distribution are achieved. In addition, the effects of the laser power, the welding speed, the laser spot diameter, and the gap between two plates on the weld shape are also studied.

scholarly journals Welding Process Optimization of WELDOX960 High Strength Steel

2018 ◽  
Vol 207 ◽  
pp. 04005
Author(s):  
Min Hu
Keyword(s):  
Penetration Depth ◽  
Process Optimization ◽  
Process Parameters ◽  
Welding Speed ◽  
High Strength Steel ◽  
Welding Process ◽  
Welding Current ◽  
High Strength ◽  
Influence Of Process Parameters ◽  
Steel Analysis

This paper studies WELDOX960 high strength steel, analysis of the welding ability of WELDOX960 high strength steel. Analyze the weld ability of WELDOX960 high-strength steel materials, and study the influence of process parameters such as welding current, welding voltage, and welding speed on penetration depth and weld width in the automated welding process. Through this test, the welding process is optimized to ensure the weld quality. The results show that WELDOX960 high-strength steel adopts multi-layer and multi-pass welding to form better welds.

Effect of Heat Treatment on Corrosion and Fracture Behavior of SPV50Q High Strength Steel Weldment in H2S-Containing Environment

2008 ◽  
Author(s):  
Jianqun Tang ◽  
Jian-Ming Gong ◽  
Luyang Geng ◽  
Jiang Yong
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Residual Stress ◽  
High Strength Steel ◽  
Fracture Behavior ◽  
High Strength ◽  
Optical Microscope ◽  
Welding Residual Stress ◽  
Liquefied Petroleum Gas ◽  
Steel Weldment

SPV50Q high strength steel is often used to fabricate liquefied petroleum gas (LPG) spherical tanks with larger capacity, and tanks are expected to free post weld heat treatment (PWHT) for avoiding the possible reduction in strength. Sulfide stress corrosion cracking (SSCC), however, has been found in weldment, especially the heat-affected zone (HAZ), in LPG environment contaminated by wet H2S. The failure analysis showed that the existence of welding residual stress in weldment is one of the major factors in the occurrence of cracking. Post welding heat treatment (PWHT) is a feasible method of reducing welding residual stress. Therefore, in order to investigate the effect of heat treatment on mechanical properties, corrosion and fracture behavior of SPV50Q steel weldment, the difference in mechanical properties of the weldment with and without heat treatment at 590°C for 160 min after welding was measured using tensile test and impact test. The corrosion behaviors of base metal (BM), weld metal (WM) and HAZ metal in the weldment were investigated by potentiodynamic polarization in H2S-containing solution. In the same solution, the susceptibility to environmental cracking was evaluated by slow strain rate testing (SSRT). The feature of fracture and the morphologies of cracks were observed by scanning electrode microscope (SEM) and optical microscope (OP). The results indicate that the execution of heat treatment does not greatly change the properties of SPV50Q steel weldment, which can provide technology support for the remanufacturing of the LPG tanks having suffered from SSCC by repair welding following local or integral heat treatment.

scholarly journals Comparison of Residual Stress in High Strength Steel Sample before and after Laser Welding

2018 ◽  
Vol 18 (3) ◽  
pp. 369-371 ◽  
Author(s):  
Mária Blatnická ◽  
Michal Šajgalík ◽  
Milan Sága ◽  
Miroslav Blatnický
Keyword(s):  
Residual Stress ◽  
Laser Welding ◽  
High Strength Steel ◽  
High Strength ◽  
Steel Sample ◽  
Before And After

scholarly journals Numerical study on the effect of welding and heating treatments on strength of high strength steel column

2018 ◽  
Author(s):  
Jiang Jin ◽  
Wei Bao ◽  
J. Liu ◽  
Z.Y. Peng
Keyword(s):  
Residual Stress ◽  
High Strength Steel ◽  
Arc Welding ◽  
Numerical Study ◽  
Welding Process ◽  
High Strength ◽  
Residual Stress Field ◽  
Heating Treatment ◽  
Welding Processes ◽  
Box Columns

High strength steel box columns are usually fabricated from steel slab by applying welding. The welding process can introduce residual stresses and geometric imperfections into the columns and influence the column strength. In this study, a numerical investigation on the behavior of high strength steel thin-walled box columns under the compression force was carried out. The welding processes were firstly simulated with commercial package ABAQUS in this study to find out the residual stress distributions in high strength steel box column. After that, the column behaviors under the compression were modelled with predefined field from the previous step. The effect of the welding process (including flux-core arc welding and submerged arc welding), heating treatment (including preheating and post-weld heat treatment) and geometrical imperfection on the residual stress field and box column strength was investigated and discussed.   

Study on Laser Welding Residual Stress of High Strength Steel

2015 ◽  
Vol 42 (6) ◽  
pp. 0603007
Author(s):  
伍强 Wu Qiang ◽  
徐兰英 Xu Lanying ◽  
杨永强 Yang Yongqiang ◽  
孔春玉 Kong Chunyu
Keyword(s):  
Residual Stress ◽  
Laser Welding ◽  
High Strength Steel ◽  
High Strength ◽  
Welding Residual Stress

scholarly journals Residual Stress in Laser Welding of TC4 Titanium Alloy Based on Ultrasonic laser Technology

2018 ◽  
Vol 8 (10) ◽  
pp. 1997 ◽  
Author(s):  
Yu Zhan ◽  
Enda Zhang ◽  
Yiming Ge ◽  
Changsheng Liu
Keyword(s):  
Residual Stress ◽  
Titanium Alloy ◽  
Laser Welding ◽  
Welding Speed ◽  
Heat Input ◽  
Welding Process ◽  
High Energy ◽  
High Energy Density ◽  
Tc4 Titanium Alloy ◽  
Longitudinal Residual Stress

Laser welding is widely used in titanium alloy welding due to its high energy density, small heat affected zone, and rapid processing ability. However, problems with laser welding, such as deformation and cracking caused by residual stress, need to be resolved. In this paper, the residual stress in laser welding of TC4 titanium alloy was studied using an ultrasonic laser. The residual stress in titanium alloy plates is considered a plane stress state. A pre-stress loading method is proposed and acoustoelastic coefficients are obtained. Based on the known acoustoelastic coefficients, the transverse and longitudinal residual stresses in laser welding are measured using an ultrasonic laser. The results show that longitudinal residual stress is greater than the transverse stress. The distribution regularity of the residual stress is similar to normal welding, but the tensile stress zone is much narrower. Then, the influence of heat input and welding speed on residual stress is discussed. With increasing heat input, the welding zone widens, and the peak value of the residual stress increases. A higher welding speed should be chosen when the welding power is constant. This research has important significance for the measurement and control of residual stress in the laser welding process.

Real-time Process Monitoring of Laser Welding by Infrared Camera and Image Processing

2020 ◽  
Vol 856 ◽  
pp. 160-168
Author(s):  
Boonrit Kaewprachum ◽  
Pornsak Srisungsitthisunti
Keyword(s):  
Laser Welding ◽  
Real Time ◽  
Welding Speed ◽  
Molten Pool ◽  
Laser Power ◽  
Rapid Heating ◽  
Welding Process ◽  
Infrared Camera ◽  
Low Carbon ◽  
Welding Processes

Understanding and predicting relationships between laser welding process parameters, such as laser power and welding speed, and molten pool have been studied widely in order to critically control and improve laser welding. The laser welding processes are difficult to monitor in real time because of high temperature and rapid heating characteristics. In this study, infrared camera was set to collect data and provide real time monitoring system to determine the molten pool characteristics and weld quality. This study carried out a laser welding of SS400 low carbon steel and analyzed real-time image of the welding process to determine the average temperature of molten pool and calculate the size of molten pool. By varying the laser power and the welding speed, the infrared camera and imaging processing technique can monitor change of molten pool temperature in a range of 1000 C to 15000 C with about 1% temperature fluctuation. In addition, the size of molten pool can be calculated from the temperature profile of the welding zone. The calculated molten pool size was about 95% accurate compared to the measured size from microscope imaging.

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