Investigation of High-Intensity Beam Characteristics on Welding Cavity Shape and Temperature Distribution

1990 ◽  
Vol 112 (1) ◽  
pp. 163-169 ◽  
Author(s):  
P. S. Wei ◽  
T. H. Wu ◽  
Y. T. Chow
Keyword(s):  
Temperature Distribution ◽  
Thermal Property ◽  
Energy Flux ◽  
High Intensity ◽  
Flux Distribution ◽  
Welding Process ◽  
Local Heat Transfer ◽  
Distribution Parameter ◽  
Beam Power ◽  
Cavity Shape

A model for investigating the characteristics of a high-intensity beam on welding cavity shape and temperature distribution is developed. The beam power density is assumed to have a Gaussian distribution. The local heat transfer rate to the liquid-vapor interface depends on this distribution and on the interface contour. This contour as determined by an iterative procedure involves simultaneously satisfying the heat conduction rate into the liquid and equilibrium of the normal forces. Computed shapes of the cavity and the free surface temperature distributions agree well with experimental data. The beam energy flux distribution parameter is found to have the strongest effect on the welding process. The predicted dimensionless curve of the beam power-penetration depth parameter versus the welding velocity-thermal property parameter is also in accord with experimental results. The use of the energy flux distribution parameter instead of the fusion zone width at the workpiece surface for the welding velocity-thermal property parameter is recommended.

A Simplified Numerical Approach for Finding the Temperature Distribution in Submerged arc Welding Process

2012 ◽  
Vol 622-623 ◽  
pp. 315-318
Author(s):  
Aparesh Datta ◽  
Subodh Debbarma ◽  
Subhash Chandra Saha
Keyword(s):  
Temperature Distribution ◽  
Heat Source ◽  
Arc Welding ◽  
Welding Process ◽  
Numerical Approach ◽  
High Heat ◽  
Submerged Arc Welding ◽  
Fusion Welding ◽  
Arc Welding Process ◽  
Submerged Arc

The quality of joining has assumed a greater role in fabrication of metal in recent years, because of the development of new alloys with tremendously increased strength and toughness. Submerged arc welding is a high heat input fusion welding process in which weld is produced by moving localized heat source along the joint. The weld quality in turn affected by thermal cycle that the weldment experiences during the welding. In the present study a simple comprehensive mathematical model has been developed using a moving heat source and analyzing the temperature on one section and then the temperature distribution of other section are correlated with time delay with reference analyzed section.

scholarly journals Hybrid laser-arc welding of laser- and plasma-cut 20-mm-thick structural steels

2022 ◽  
Author(s):  
Ömer Üstündağ ◽  
Nasim Bakir ◽  
Sergej Gook ◽  
Andrey Gumenyuk ◽  
Michael Rethmeier
Keyword(s):  
Laser Beam ◽  
Arc Welding ◽  
Laser Beam Welding ◽  
Digital Camera ◽  
Welding Process ◽  
Beam Power ◽  
Beam Diameter ◽  
Hybrid Laser Arc Welding ◽  
Single Pass ◽  
New Findings

AbstractIt is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively. Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges.

scholarly journals Study of Laser Welding of HCT600X Dual Phase Steels

2014 ◽  
Vol 22 (1) ◽  
pp. 93-98
Author(s):  
Pavol Švec ◽  
Viliam Hrnčiar ◽  
Alexander Schrek
Keyword(s):  
Tensile Strength ◽  
Base Metal ◽  
Heat Affected Zone ◽  
Welding Speed ◽  
Welding Process ◽  
Beam Power ◽  
Welding Parameters ◽  
Dual Phase ◽  
Welded Steel ◽  
Steel Sheets

AbstractThe effects of beam power and welding speed on microstructure, microhardnes and tensile strength of HCT600X laser welded steel sheets were evaluated. The welding parameters influenced both the width and the microstructure of the fusion zone and heat affected zone. The welding process has no effect on tensile strength of joints which achieved the strength of base metal and all joints fractured in the base metal.

Evaluation by FEM of the Influence of the Preheating and Post-Heating Treatments on Residual Stresses in Welding

2014 ◽  
Vol 627 ◽  
pp. 93-96 ◽  
Author(s):  
Raffaele Sepe ◽  
Enrico Armentani ◽  
Giuseppe Lamanna ◽  
Francesco Caputo
Keyword(s):  
Temperature Distribution ◽  
Residual Stresses ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
Element Model ◽  
Butt Joint ◽  
Temperature Fields ◽  
Heating Process ◽  
Butt Weld ◽  
Metal Arc Welding

During the last few years various experimental destructive and non-destructive methods were developed to evaluate residual stresses. However it is impossible to obtain a full residual stress distribution in welded structures by means of experimental methods. This disadvantage can be solved by means of computational analysis which allows to determine the whole stress and strain fields in complex structures. In this paper the temperature distribution and residual stresses were determined in a single-pass butt joint welded by GMAW (Gas Metal Arc Welding) process by finite element model (FEM). A 3D finite parametric element model has been carried out to analyze temperature distribution in butt weld joints and thermo-mechanical analyses were performed to evaluate resulting residual stresses. Temperature fields have been investigated by varying an initial preheating treatment. Moreover the technique of “element birth and death” was adopted to simulate the process of filler metal addition The high stresses were evaluated, with particular regard to fusion zone and heat affected zone. The influence of preheating and post-heating treatment on residual stresses was investigated. The residual stresses decrease when preheating temperature increases. The maximum value of longitudinal residual stresses without pre-heating can be reduced about 12% and 38% by using the preheating and post-heating process respectively.

Intense X-Ray Measurement of Transient Hydraulic Phenomena in Molten Pool During Laser Welding Process

2012 ◽  
Author(s):  
Tomonori Yamada ◽  
Takahisa Shobu ◽  
Susumu Yamashita ◽  
Takemitsu Ogawa ◽  
Kenta Sugihara ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Laser Welding ◽  
Phase Change ◽  
Molten Pool ◽  
Welding Process ◽  
In Situ Observation ◽  
Interface Shape ◽  
X Ray ◽  
Laser Welding Process

Spatial temperature distribution during the laser welding process has a huge effect on any residual stress distribution. Therefore, understanding of the transient hydraulic phenomena which affect the temperature distribution in the molten pool is very important. In this work, intense X-ray measurement at the Super Photon ring-8 GeV (SPring-8) facility well carried out to document the transient hydraulic phenomena in the molten pool during the laser welding process. Based on in-situ observation of inside material, the experimental results confirmed that the molten pool shapes, hydraulic condition such as flow velocity, etc.. In the case of laser power is 330W and spot diameter is 1mm, we observed the steady flow which consisted of downward flow and upward flow. The flow velocities were about 19.5 mm/s and 9.0 mm/s, respectively. Moreover, the rate of phase change was obtained from molten pool shape during laser welding. The rate of phase change was not constant during laser welding. Thus the interface shape might change at all time. Therefore, to evaluate the temperature distribution, it is necessary to consider not only convection but also the interface shape. These results indicate that the intense X-ray measurement during laser welding is very effective for the understanding the molten pool phenomena.

Prediction of Temperature Distribution on Submerged Arc Welded Plates through Gaussian Heat Distribution Technique

2011 ◽  
Vol 284-286 ◽  
pp. 2477-2480 ◽  
Author(s):  
Aniruddha Ghosh ◽  
Somnath Chattopadhyaya
Keyword(s):  
Temperature Distribution ◽  
Arc Welding ◽  
Infinite Plate ◽  
Welding Process ◽  
Submerged Arc Welding ◽  
High Deposition Rate ◽  
Microstructure Modeling ◽  
Arc Welding Process ◽  
Submerged Arc ◽  
Good Agreement

Submerged Arc Welding process (SAW) is a high quality, very high deposition rate welding process. It has lot of social and economical implecations.This paper makes an attempt to uncover an important area on studies of temperature distribution during submerged arc welding because this may pave the way for application of microstructure modeling, thermal stress analysis, residual stress/distribution and welding process simulation. Prediction of temperature variation of entire plates during welding through an analytical solution is derived from the transient multi dimensional heat conduction of semi infinite plate. The heat input that is applied on the plate is exactly same amount of heat lost for electric arc, which is assumed to be a moving double conical heat source with Gaussian distribution for Submerged Arc Welding process. Good agreement between predicted and experimental results has been achieved.

scholarly journals Why are Temperature and Upward Wave Activity Flux Positively Skewed in the Polar Stratosphere?

2017 ◽  
Vol 31 (1) ◽  
pp. 115-130 ◽  
Author(s):  
Oliver Watt-Meyer ◽  
Paul J. Kushner
Keyword(s):  
Temperature Distribution ◽  
Planetary Wave ◽  
Flux Distribution ◽  
Wave Activity ◽  
Nonlinear Dependence ◽  
Radiative Balance ◽  
Wave Phase ◽  
Wave Interference ◽  
Polar Stratosphere ◽  
Wave Activity Flux

Abstract The distribution of temperatures in the wintertime polar stratosphere is significantly positively skewed, which has important implications for the characteristics of ozone chemistry and stratosphere–troposphere coupling. The typical argument for why the temperature distribution is skewed is that radiative balance sets a firm lower limit, while planetary wave driving can force much larger positive anomalies in temperature. However, the distribution of the upward Eliassen–Palm (EP) flux is also positively skewed, and this suggests that dynamics may play an important role in setting the skewness of the temperature distribution. This study explains the skewness of the upward EP flux distribution by appealing to the ideas of linear interference. In this framework, fluxes are decomposed into a linear term (LIN) that measures the coherence of the wave anomaly and the climatological wave and an additional nonlinear term (NONLIN) that depends only on the wave anomaly. It is shown that when filtered by wavenumber, there is a clear nonlinear dependence between LIN and NONLIN: the terms cancel when LIN is negative, but they reinforce each other when LIN is positive. This leads to the positive skewness of the upward wave activity flux. A toy model of wave interference is constructed, and it is shown that the westward vertical tilt of the climatological wave is the key ingredient to a positively skewed upward EP flux distribution. The causes of the skews of the LIN and NONLIN distributions themselves are shown to be related to relationships between wave phase and amplitude, and wave phase and vertical tilt, respectively.

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