Effect of power distribution on the temperature evolution in laser-MIG hybrid welding for Q235 Steel

2019 ◽  
Vol 33 (32) ◽  
pp. 1950405
Author(s):  
Shujun Zhou ◽  
Hengchang Bu ◽  
Qiyu Gao ◽  
Weihua Lu ◽  
Xiaohong Zhan
Keyword(s):  
Heat Source ◽  
Power Distribution ◽  
Molten Pool ◽  
Simulation Software ◽  
Temperature Evolution ◽  
Width Ratio ◽  
Hybrid Welding ◽  
Heat Accumulation ◽  
Q235 Steel ◽  
Validation Experiment

Numerical simulation of laser-MIG hybrid welded Q235 steel was conducted using finite element simulation software with a 3D model. The thermal analysis was performed with a combined ellipsoid-Gaussian heat source. Double ellipsoid heat source and Gaussian heat source (Gauss rotating body heat source and Gauss cylinder heat source) were utilized to represent arc and laser heat, respectively. The effects of power distribution on the temperature evolution and the geometry of molten pool were numerically investigated. The simulated temperature field shows that the increase of the power ratio of laser in laser-MIG hybrid welding (LMHW) is more conducive to improve the peak temperature, leading to remelt interlayer and promote interlayer heat accumulation. Meanwhile, the depth-to-width-ratio (DTW) of molten pool increases with the risen laser power. The change of DTW value with [Formula: see text] value is more obvious when the [Formula: see text] value is greater than 1. Comparison of the calculated and validation experiment results suggested that the LMHW process is characterized well by the combined heat source model. Fine weld joint with good shape of molten pool morphology is obtained when the DTW of first pass, second pass and third pass are 0.94, 0.34 and 0.27, respectively.

scholarly journals CFD-based modelling of phase transformation in laser welded low-carbon steel

2021 ◽  
Author(s):  
Aleksander Siwek
Keyword(s):  
Heat Source ◽  
Phase Transformations ◽  
Power Distribution ◽  
Low Carbon Steel ◽  
Marangoni Effect ◽  
Phase Changes ◽  
Test Material ◽  
Low Carbon ◽  
Welding Condition ◽  
Welding Pool

AbstractThis paper presents a numerical model of the laser welding of steel, taking into account the heat and mass flows, as well as thermal effects associated with phase transformations. It was assumed that the heat source is a laser with a symmetrical power distribution of the TEM10 beam in two welding condition variants: a stationary heat source and a source moving at a constant speed along the sample. After reaching the melting temperature, the movement of the liquid phase was forced by the Marangoni effect acting on the surface of the welding pool. For the laser power applied, the surface of the welding pool was assumed to be flat. It was proposed an algorithm for the forecasting of the phase changes during heating and cooling. Diffusive phase transformations during cooling were modelled using Johnson-Mehl-Avrami-Kolmogorov (JMAK) equations. Diffusionless transformations occurring when cooling rates exceed the critical ones were modelled using Koistinen-Marburger (KM) equations. Calculations were made for a rectangular sample welded in air and cooled spontaneously in the atmosphere. The boundary conditions were simulated assuming a constant coefficient of heat exchange and radiation to the environment. The start and end time of the changes occurring in the cooling phase were calculated based on the average cooling rate in the temperature range 800–500°C (v8/5). The model was tested for the test material: S355J2 steel.

Microstructure and mechanical properties of double-wire feed GTA additive manufactured 308L stainless steel

2020 ◽  
Vol 26 (9) ◽  
pp. 1503-1513
Author(s):  
Yang Ke ◽  
Jun Xiong
Keyword(s):  
Mechanical Properties ◽  
Stainless Steel ◽  
Cooling Rate ◽  
Molten Pool ◽  
Heat Accumulation ◽  
Steel Component ◽  
Content Type ◽  
Wire Feeding ◽  
Novel Concept ◽  
Wire Feed

Purpose This paper aims to introduce a novel concept of a double-wire feed (DWF) to alleviate heat accumulation and improve the cooling rate of the molten pool in gas tungsten arc (GTA)-based additive manufacturing (AM), in which the former wire is fed into the arc and the latter wire is melt by the molten pool. Design/methodology/approach The microstructure, phase composition and mechanical properties of 308 L stainless steel components built by single-wire feed (SWF) AM and DWF-AM are compared, and the differences are analyzed in detail. Findings The microstructures for both wire feeding modes include δ and γ phases. Compared with the SWF-AM, the sample fabricated in the DWF-AM exhibits finer microstructure, and the microstructure in the middle region is transformed from columnar grains to cellular grains. Microhardness of the sample produced in the DWF-AM is higher than the SWF-AM. In comparison to the SWF-AM, the tensile strength of the specimen fabricated using the DWF-AM reaches 571 MPa and increases by 16.14%. Originality/value This study proposes a novel concept of the DWF-AM to reduce heat accumulation as well as enhance the cooling rate of the molten pool, and improved mechanical properties of the 308 L stainless steel component are obtained.

The New Heat Source Model of AZ31B Magnesium Alloy Laser-TIG Hybrid Welding

2019 ◽  
Vol 815 ◽  
pp. 120-124 ◽  
Author(s):  
Zhong Lin Hou ◽  
Tan Zhao ◽  
Zhen Xu ◽  
Long Hao Zhu ◽  
Jian Hua Sun ◽  
...  
Keyword(s):  
Magnesium Alloy ◽  
Heat Source ◽  
Weld Pool ◽  
Inflection Point ◽  
Source Model ◽  
Hybrid Welding ◽  
Single Source ◽  
Heat Source Model ◽  
Keyhole Effect ◽  
Body Heat

A new heat source model consisted of inverted conical heat source and rotary Gauss body heat source is established using the CAE software for the keyhole effect of laser-TIG hybrid welding. The inverted conical heat source is used for analyzing the wide upper part of weld pool due to the rapid heat up by the laser and arc. The rotary Gauss body heat source model is used for analyzing the long and narrow lower part of weld pool formed by the laser. The result showed that, compared with other single source mode, this new heat source model may get a better simulation of the weld pool morphology, especially the inflection point near the keyhole. It provides a new method to predict the morphology and size of the weld pool of magnesium alloy laser-TIG welding.

scholarly journals Finite element simulation and microstructure analysis of nickel based alloy for additive manufacturing

2018 ◽  
Vol 242 ◽  
pp. 01022
Author(s):  
Liu Heping ◽  
Sun Fenger ◽  
Yibo Fenger ◽  
Cheng Shaolei ◽  
Liu Bin
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Temperature Gradient ◽  
Heat Source ◽  
Finite Element Simulation ◽  
Molten Pool ◽  
Laser Melting ◽  
Front End ◽  
Element Simulation ◽  
Laser Heat Source

In this paper, the finite element simulation of GH4169 high temperature alloy by selective laser melting was carried out, and the microstructure was analyzed by experiments. The results show that the shape of the temperature field cloud formed by the laser heat source is different from the shape of the theoretical model, but is in the shape of the ellipse. The temperature gradient at the front end of the molten pool is larger than that of the back end of the molten pool, and the isotherm of the front end of the molten pool is more intensive. The temperature of the substrate is less affected by the temperature gradient. The temperature gradient of the front end of the melting pool is larger than the back end of the molten pool, and the temperature field of selective laser melting is like a meteor with trailing tail. In the laser heat source, the temperature isotherm is the most dense and the temperature gradient is maximum. The relative effect of mechanical properties of δ phase is very complex. When the phase is precipitated by widmanstatten structure, it is easy to produce stress concentration as a source of cracks

A Study on the Grinding Temperature Field for Titanium Alloy

2007 ◽  
Vol 339 ◽  
pp. 45-49
Author(s):  
W. Li ◽  
Tong Xing ◽  
Bao Xiang Qiu ◽  
Gang Xiang Hu ◽  
Yang Fu Jin
Keyword(s):  
Finite Element ◽  
Temperature Field ◽  
Heat Source ◽  
Simulation Software ◽  
Transient Temperature ◽  
Fe Model ◽  
Grinding Temperature ◽  
Wet Grinding ◽  
Dry Grinding ◽  
Grinding Temperature Field

A reasonable finite element (FE) model of grinding temperature field has been developed on the basis of analysis of the transient temperature field， and three kinds of boundary conditions are loaded on the element of a moving heat source. The study, which is based on the finite element principle, has been carried out using the numerical simulation software ANSYS. Many results have been obtained including three dimensional temperature distribution map. The simulated results under different conditions show good agreement with the experimental results. With the comparison of the dry-grinding and wet-grinding, the result shows that the wet-grinding temperature with a proper grinding fluid is rather lower than the dry-grinding temperature. Finally, the variable coefficient of convective heat transfer and the different form heat source have been discussed in detail.

Comparison on welding mode characteristics of arc heat source for heat input control in hybrid welding of aluminum alloy

2015 ◽  
Vol 29 (06n07) ◽  
pp. 1540016
Author(s):  
Moo-Keun Song ◽  
Jong-Do Kim ◽  
Jae-Hwan Oh
Keyword(s):  
Experimental Study ◽  
Aluminum Alloy ◽  
Heat Source ◽  
Laser Welding ◽  
Heat Input ◽  
Heat Sources ◽  
Hybrid Welding ◽  
Input Control ◽  
Mode Characteristics ◽  
Pulsed Arc

Presently in shipbuilding, transportation and aerospace industries, the potential to apply welding using laser and laser-arc hybrid heat sources is widely under research. This study has the purpose of comparing the weldability depending on the arc mode by varying the welding modes of arc heat sources in applying laser-arc hybrid welding to aluminum alloy and of implementing efficient hybrid welding while controlling heat input. In the experimental study, we found that hybrid welding using CMT mode produced deeper penetration and sounder bead surface than those characteristics produced during only laser welding, with less heat input compared to that required in pulsed arc mode.

Numerical simulation of flow field in the Invar alloy laser–MIG hybrid welding pool based on different heat source models

2018 ◽  
Vol 28 (4) ◽  
pp. 909-926 ◽  
Author(s):  
Xiaohong Zhan ◽  
Qi Zhang ◽  
Qibing Wang ◽  
Jie Chen ◽  
Hongbing Liu ◽  
...  
Keyword(s):  
Flow Field ◽  
Heat Source ◽  
Welding Process ◽  
Source Model ◽  
Invar Alloy ◽  
Heat Sources ◽  
Hybrid Welding ◽  
Mig Welding ◽  
Content Type ◽  
Source Models

Purpose The purpose of this paper is to establish a three-dimensional flow field model of the Invar alloy laser–metal inert gas (laser–MIG) hybrid welding process to investigate the influence of different heat sources between different layers and to analyze the flow field based on the two different heat source models for the multilayer welding. Design/methodology/approach The Invar steel plates with 19.5 mm thickness are welded into three layers’ seam using the hybrid laser–MIG welding technology. The flow field based on different heat source models is studied and then used to investigate the influence of different heat sources in different layers during the laser–MIG hybrid welding process. The simulation results of flow field using two different heat source models are compared with experiments. Findings The flow field simulations results show that using the Gaussian rotating body heat source model to simulate the temperature field is more consistent with the experiment of the hybrid laser–MIG welding where its flow field between different layers better reflects the characteristics of the hybrid laser–MIG welding. Originality/value The findings will be useful in the study of a variety of thick-plate laser–MIG hybrid welding process fluid flows.

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