scholarly journals The Effects of Different Gaps on the Weld Morphology, Microstructure and Residual Stress of AH36 Steel were Studied by Laser Arc Hybrid Welding

2022 ◽  
Vol 2160 (1) ◽  
pp. 012039
Author(s):  
Xiaoqi Hou ◽  
Xin Ye ◽  
Xiaoyan Qian ◽  
Haohao Jing ◽  
Peilei Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Process Parameters ◽  
Heat Affected Zone ◽  
Laser Power ◽  
Welding Process ◽  
Lower Surface ◽  
Thick Sheet ◽  
Hybrid Welding ◽  
Upper Bainite ◽  
Better Than

Abstract In this study, laser (TruDisk16002)-arc (MAG) hybrid welding was used to weld a 5mm thick sheet of AH36 steel with a gap of 0mm and 1mm. The results show that when the current of MAG is 205A, the voltage is 31.9V, and the laser power is 7.5KW, the welds of 0mm gap and 1mm gap are well formed, showing a typical nail shape, and the 0mm gap weld is better than 1mm. Under the same welding process parameters, the heat-affected zone of a 0mm gap weld is less than 1mm. Upper bainite is found in the 1mm weld gap structure. In the two gap cases, the residual stress on the lower surface is larger than that on the upper surface, and the residual stress in the 1mm weld gap is larger. The weldability of 0mm weld gap is better than 1mm.

Experimental Investigation on Laser Transmission Welding of Polycarbonate and Acrylic

2021 ◽  
pp. 160-180
Author(s):  
Dhiraj Kumar ◽  
Sudipta Paitandi ◽  
Arunanshu Shekhar Kuar ◽  
Dipankar Bose
Keyword(s):  
Mathematical Model ◽  
Process Parameters ◽  
Welding Speed ◽  
Laser Power ◽  
Optimum Parameter ◽  
Optimization Technique ◽  
Welding Process ◽  
Parameter Setting ◽  
Laser Transmission Welding ◽  
Weld Width

This chapter presents the effect of various process parameters, namely laser power, pulse frequency, and welding speed, on the weld shear strength and weld width using a diode laser system. Here, laser transmission welding of transparent polycarbonate and black carbon filled acrylic each of 2.8 mm thickness have been performed to create lap joint by using low power laser. Response surface methodology is applied to develop the mathematical model between the laser welding process parameters and the responses of weld joint. The developed mathematical model is tested for its adequacy using analysis of variance and other adequacy measures. It has been observed that laser power and welding speed are the dominant factor followed by frequency. A confirmation test has also been conducted to validate the experimental results at optimum parameter setting. Results show that weld strength of 34.3173 N/mm and weld width of 2.61547 mm have been achieved at optimum parameter setting using desirability function-based optimization technique.

scholarly journals Process Induced Residual Stress Effect on Fatigue Lifetime of Automotive Steel Components

2014 ◽  
Vol 996 ◽  
pp. 808-813
Author(s):  
Elias Merhy ◽  
Ngadia Taha Niane ◽  
Bastien Weber ◽  
Philippe Bristiel
Keyword(s):  
Residual Stress ◽  
Heat Affected Zone ◽  
High Cycle Fatigue ◽  
Low Cycle Fatigue ◽  
Welding Process ◽  
Fatigue Loading ◽  
Stress Effect ◽  
Cycle Fatigue ◽  
Residual Stress Field ◽  
Fatigue Lifetime

Metal Active Gas (MAG) welding process of steel sheets generates, in the vicinity of the welding joint, the well-known Heat Affected Zone (HAZ) in which the material presents more microstructural defects compared to the original metal. Since high cycle fatigue is largely dependent on the material microstructure features, the HAZ is considered as the weakest zone under high cycle fatigue loading. In addition, the welding causes, in the Heat Affected Zone, irreversible plastic strains that induce important residual stress fields in this critical zone of the structure. Therefore, in order to properly predict the high cycle fatigue life time of the welded automotive components, it is of primordial importance to first identify and then consider, if necessary, the welding induced residual stress field in the structure modeling. In this work, it is found that residual stresses have non-negligible impact on high cycle fatigue lifetime, while its effect is minor in the low cycle fatigue domain.

scholarly journals Research on Residual Stress Distribution in Different Areas of Laser-MAG Arc Hybrid Welding by Numerical Simulation

2022 ◽  
Vol 2160 (1) ◽  
pp. 012026
Author(s):  
Xiaoyan Qian ◽  
Xin Ye ◽  
Xiaoqi Hou ◽  
Haohao Jing ◽  
Peilei Zhang ◽  
...  
Keyword(s):  
Residual Stress ◽  
Stress Distribution ◽  
Cross Section ◽  
Laser Power ◽  
Residual Stress Distribution ◽  
Bottom Surface ◽  
Hybrid Welding ◽  
Welding Seam ◽  
Mixed Zone ◽  
Arc Power

Abstract In this research, through experiments and numerical simulations, the residual stress distribution of the top and bottom surfaces of the laser (TruDisk16002)-arc (MAG) hybrid welding seam and the weld cross-section are studied. The results show that when the arc power is 6.5KW and the laser power is 7.5KW, the weld is formed well. The residual stress on the bottom surface near the weld is higher than that on the top surface. The laser zone in the center of the weld has the largest residual stress, the arc zone is smaller, and the mixed zone is the smallest. The laser zone has the largest residual stress at the fusion line and the heat-affected zone, followed by the mixed zone, and the arc zone is the smallest. followed by the mixed zone, and the arc zone has the smallest.

scholarly journals Shielded Metal Arc and Thermite Welding Effect to Residual Stress, Hardness and Crack of R54-Rail Weld Joint

2020 ◽  
Vol 55 (4) ◽  
Author(s):  
Yurianto ◽  
Gunawan Dwi Haryadi ◽  
Sri Nugroho ◽  
Sulardjaka ◽  
Susilo Adi Widayanto
Keyword(s):  
Residual Stress ◽  
Residual Stresses ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welded Joints ◽  
Arc Welding ◽  
Welding Process ◽  
Shielded Metal Arc Welding ◽  
Metal Arc Welding ◽  
Crack Susceptibility

The heating and cooling at the end of the welding process can cause residual stresses that are permanent and remain in the welded joint. This study aims to evaluate the magnitude and direction of residual stresses on the base metal and heat-affected zone of rail joints welded by the manual shielded metal arc and thermite welding. This research supports the feasibility of welding for rail. The material used in this study is the R-54 rail type, and the procedure used two rail samples of one meter long each, welded using manual shielded metal arc welding and thermite welding. The base metal and heat-affected zone of the welded joints were scanned with neutron ray diffraction. The scan produces a spectrum pattern and reveals the direction of the residual stress along with it. We found the strain value contained in both types of welded joints by looking at the microstrain values, which we obtained using the Bragg equation. The results show that the magnitude and direction of the residual stress produced by manual shielded metal arc welding and thermite welding are not the same. Thermite welding produces lower residual stress (lower crack susceptibility) than manual shielded metal arc welding. The melt's freezing starts from the edge to the center of the weld to create random residual stresses. The residual stress results of both the manual shielded metal arc welding and thermite welding are still below the yield strength of the base metal.

scholarly journals Residual stress detection of welded parts based on excitation vibration response

2020 ◽  
Vol 17 (1) ◽  
pp. 172988142090518
Author(s):  
Xiaohan Liu ◽  
Guangfeng Shi
Keyword(s):  
Residual Stress ◽  
Process Parameters ◽  
High Frequency ◽  
Rapid Development ◽  
Welding Process ◽  
Vibration Signal ◽  
Resonance Analysis ◽  
Orthogonal Parameters ◽  
Set Up ◽  
High Frequency Induction

With the rapid development of the equipment industry, people pay more attention to the stress research of materials. However, there is no more suitable and effective method to detect the variation of residual stress. To find an efficient and useful method to analyze the residual stress of the welded parts, this article selects the Q235 component as the research object and produces a detection robot with the core of processing vibration signal and extracting signal data. In combination with the vibration signal extracted by the robot, we study the influence law of the residual stress of the material through numerical simulation and experimental verification. The detection of residual stress is related to the change in the number of taps of the robot and the increase or decrease in the number of taps of the robot. We used the vibration signal extracted by the robot and analyzed the orthogonal parameters of the high-frequency induction welding process parameters to obtain a set of the most unique process parameters: The tapping angle was 7° and the tapping frequency was 300 Hz. We also set up the robot to extract and analyze the vibration signal using four different hammerheads. The results show that the sub-resonance analysis results as the standard, the deviation of the steel head and the aluminum head hammer is about ±10, the result is more accurate, and the frequency of the nylon and plastic hammer is lower, because it is softer. When the hammer is struck, the contact time of the hammerhead with the workpiece is lengthened, so that a lower frequency can be excited.

scholarly journals Microstructure and residual stress analysis of Strenx 700 MC welded joint

2020 ◽  
Vol 26 (2) ◽  
pp. 41-44
Author(s):  
Libor Trško ◽  
Ján Lago ◽  
Michal Jambor ◽  
František Nový ◽  
Otakar Bokůvka ◽  
...  
Keyword(s):  
Residual Stress ◽  
Heat Affected Zone ◽  
Microstructural Analysis ◽  
Fatigue Crack Initiation ◽  
Welding Process ◽  
High Strength ◽  
Carbon Steels ◽  
Fatigue Properties ◽  
Residual Stress Field ◽  
Welded Structure

AbstractHigh strength low alloy (HSLA) steels are a new generation of plain carbon steels with significantly improved mechanical properties while maintaining good weldability with common commercial techniques. Residual stress and microstructural analysis of welded HSLA Strenx 700 MC was carried out in this research. Results have shown that the welding process causes significant grain coarsening in the heat affected zone. The microstructural changes are also accompanied with creation of tensile residual stress field in the weld metal and heat affected zone, reaching up-to depth of 4 mm. Tensile residual stresses are well known for acceleration of fatigue crack initiation and together with coarse grains can lead to significant decrease of the fatigue properties of the welded structure.

Shear Strength Variation for PLmT Welded Zn Coated Advanced High Strength Steels Used in Automotive Structures in Overlap Configuration

2015 ◽  
Vol 1111 ◽  
pp. 205-210
Author(s):  
Aurel Valentin Bîrdeanu
Keyword(s):  
Shear Strength ◽  
Laser Pulse ◽  
Process Parameters ◽  
Influence Factors ◽  
Welding Process ◽  
High Strength Steels ◽  
High Strength ◽  
Strong Interactions ◽  
Hybrid Welding ◽  
Advanced High Strength Steels

The paper presents the results of applying of a new hybrid welding process, i.e. Pulsed LASER-(micro)TIG (PLmT), for realizing overlap joints for Zn-coated U/AHSS thin sheets materials, used in the automotive industry for realizing car structures. The statistical influence onto the joint’s shear strength (objective function) of three hybrid welding process parameters was investigated by means of experimental design and weighted. The influence of laser pulse peak power, the average welding TIG current and the laser pulse duration was investigated for two types of Zn coated U/AHSS used in car body realization. The results revealed that the new process can be applied for the investigated materials and that joints with appropriate shear strength values can be obtained. Each combination did behave rather different in respect to the investigated process parameters and the results did reveal that rather strong interactions are in place between the influence factors (IF) for CPW 800 material. The determined models can be used to select convenient process parameters combinations in respect to minimum Zn coating damage and proper shear strength of the joints for each of the studied materials.

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.

Hybrid Welding vs Conventional Welding: A Solution to Residual Stress and Distortion Mitigation?

2017 ◽  
Author(s):  
Sébastien Gallee ◽  
Rémi Lacroix ◽  
Vincent Robin ◽  
Florence Gommez ◽  
Erwan Jourden
Keyword(s):  
Residual Stress ◽  
Heat Source ◽  
Welding Process ◽  
Quality Standard ◽  
Experimental Measurements ◽  
Hybrid Welding ◽  
Mig Welding ◽  
Steel Sheets ◽  
Laser Heat Source ◽  
Process Productivity

The present paper deals with the hybrid laser/MIG welding process, which allows to assembly high thickness steel sheets. The laser heat source added to the MIG torch improves the process productivity while respecting quality standard. The multi-pass welding simulation of a plate is presented in this paper and numerical results are compared to experimental measurements (temperature and stresses).

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