# Numerical Simulation and Experimental Analysis on Seam Feature Size and Deformation for T-Joint Laser–GMAW Hybrid Welding

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## Abstract

**:**

## 1. Introduction

## 2. Methods of Simulation and Experiment

#### 2.1. Simulation Model

#### 2.1.1. Thermal Conduction Model

_{p}is specific heat capacity, λ is thermal conductivity, t represents welding time, x, y, and z represent space coordinates, q is the volumetric internal energy generation, and T is temperature.

#### 2.1.2. Heat Source Model

_{L}is the laser heat flux, z

_{e}, z

_{i}, r

_{e}and r

_{i}represent the z-coordinates and radii of the top and bottom surfaces, respectively, r

_{c}is the distribution parameter, e is the base of the natural logarithm, Q

_{L}represents the effective laser power, and η

_{L}is the laser heat efficiency, 0.8 in this calculation.

_{1}and r

_{2}represent the arc and laser heat distribution, respectively.

#### 2.1.3. Numerical Model

#### 2.2. Experimental Setup

#### 2.2.1. Experimental Parameters

#### 2.2.2. Experimental Design

## 3. Results and Discussions

#### 3.1. Verification of Heat Source Model

#### 3.2. Effects of Incident Position

#### 3.3. Effects of Laser Power

^{−5}. The gradient corresponding to the middle width fitting line is evaluated as 5.32 × 10

^{−4}. This implies that for each 1000 W amplification in laser power, a subsequent increase in the middle width by 0.532 mm is seen. The gradient pertaining to the fitting line of minimal penetration is determined to be 2.38 × 10

^{−4}. It substantiates that for each supplemental 1000 W in laser power, the least melting depth experiences an upturn by 0.238 mm. Adjusting the experimental specific parameters, the findings have been delineated in Figure 12b. Both welding leg and fusion depth rise commensurate with higher laser power. The gradient of the leg height fitting line is computed as 1.07 × 10

^{−4}, while the gradient of the fusion depth fitting line is determined to be 2.14 × 10

^{−4}.

#### 3.4. Effects of Arc Power

^{−4}, signifying that a 1000 W enhancement in arc power corresponds to a 0.135 mm augmentation in the welding leg’s magnitude. The impact of arc power on the minimal penetration depth and the median breadth remains comparatively negligible, with slopes of the fitted lines being 5.48 × 10

^{−5}and 1.46 × 10

^{−5}, respectively. Upon assimilating the experimental characteristic parameters, the outcomes are exhibited in Figure 15b. As the wire feed velocity escalates, an upward trend is observed in both the welding leg and the fusion depth. The gradients of the respective fitted lines for leg height and fusion depth are 0.23 and 0.18.

#### 3.5. Effects of Welding Speed

^{−4}, signifying that for every 100 mm/min reduction in welding speed, the height of the welding leg augments by 0.029 mm. The slope of the middle width fitting line is −1.43 × 10

^{−3}, indicating that for every 100 mm/min reduction in welding speed, the height of the welding leg elevates by 0.143 mm. The slope of the fitted line for the minimum penetration is −5.77×10

^{−4}, meaning that for every 100 mm/min reduction in welding speed, the height of the minimum penetration amplifies by 0.057 mm. By fitting the experimental characteristic parameters, the outcomes are demonstrated in Figure 18b. Both the welding leg and fusion depth diminish as the welding speed rises. The slope of the leg height fitting line is −6.91 × 10

^{−4}, and the slope of the fusion depth fitting line is −7.15 × 10

^{−4}.

#### 3.6. Deformation Simulation Calculation

## 4. Conclusions

- The thermodynamics of the 8 mm T-joint laser–GMAW welding were virtually recreated employing the twin-pyramidal heat source model. Subsequently, the resultant empirical welding seam architecture was juxtaposed with the simulated cross-section. The close congruity reinforced the veracity of the heat source model in question.
- In the context of T-joint laser–GMAW welding, the incident angle and altitude are vital for determining the fidelity of the welding. As the incident angle escalates, the entire melt pool is displaced towards the base-plate lateral, thereby enhancing the molten expanse of the base plate. An excessive angle could pose a threat of partial welding on the flipside. An unduly high incident altitude would be susceptible to inadequate penetration of the interstitial joint surface.
- The force of the arc and the feeding of the wire subtly influence the proportionality of the welding leg in the context of laser–GMAW welding; however, their perturbation over the deepest penetration and mid-width is diminutive. As the laser strength surges, the welding leg parameters remain irrevocably stable while the middle breadth and halcyon penetration register growth. Rising welding speed is observed to constrict the dimensions of the welding leg, middle-width, and minimal penetration recess.
- The implementation of arched deformation mitigation in the middle of the T-joint laser–GMAW welding and confining the repositioning of the base plate at the optimal positions bilaterally can significantly curtail the welding deformation while bolstering the welding quality.

## Author Contributions

## Funding

## Institutional Review Board Statement

## Informed Consent Statement

## Data Availability Statement

## Conflicts of Interest

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**Figure 3.**Thermal Physical Properties of AH36 Steel. (

**a**) Incident Position P1 (Thermophysical properties). (

**b**) Incident Position P2 (Mechanical properties).

**Figure 8.**Temperature Nephogram at Different Incident Positions. (

**a**) Incident Position P1. (

**b**) Incident Position P2. (

**c**) Incident Position P3.

**Figure 9.**Experiment Result at Different Incident Positions. (

**a**) Incident Position P1. (

**b**) Incident Position P2. (

**c**) Incident Position P3.

**Figure 10.**Temperature Nephogram at Different Laser Power. (

**a**) Laser Power 4200 W. (

**b**) Laser Power 4700 W. (

**c**) Laser Power 5200 W. (

**d**) Laser Power 5700 W.

**Figure 11.**Experiment Result at Different Laser Power. (

**a**) Laser Power 5000 W. (

**b**) Laser Power 6000 W. (

**c**) Laser Power 4000 W.

**Figure 12.**Relationship between Laser Power and Welding Seam Feature Size. (

**a**) Simulation Fitting Curve. (

**b**) Experiment Fitting Curve.

**Figure 13.**Temperature Nephogram at Different Arc Power. (

**a**) Arc Power 5500 W. (

**b**) Arc Power 6500 W. (

**c**) Arc Power 7000 W. (

**d**) Arc Power 7500 W.

**Figure 14.**Experiment Result at Different Wire Feeding. (

**a**) Wire Feeding 11.8 mm/min. (

**b**) Wire Feeding 13.3 mm/min. (

**c**) Wire Feeding 10.3 mm/min.

**Figure 15.**Relationship between Arc Power and Welding Seam Feature Size. (

**a**) Simulation Fitting Curve. (

**b**) Experiment Fitting Curve.

**Figure 16.**Temperature Nephogram at Different Welding Speed. (

**a**) Welding Speed 2200 mm/min. (

**b**) Welding Speed 2300 mm/min. (

**c**) Welding Speed 2400 mm/min. (

**d**) Welding Speed 2600 mm/min.

**Figure 17.**Experiment Result at Different Welding Speeds. (

**a**) Welding Speed 1500 mm/min. (

**b**) Welding Speed 1800 mm/min. (

**c**) Welding Speed 1200 mm/min.

**Figure 18.**Relationship between Welding Speed and Seam Feature Size. (

**a**) Simulation Fitting Curve. (

**b**) Experiment Fitting Curve.

**Figure 19.**Welding Deformation Simulation Result in Free State. (

**a**) Deformation in X Direction (

**b**) Deformation in Y Direction. (

**c**) Deformation in Z Direction. (

**d**) Deformation in Z Direction Magnified by 10 Times.

**Figure 21.**Simulation Results of Welding Deformation after Reverse Deformation Limitation. (

**a**) Deformation in X Direction. (

**b**) Deformation in Y Direction. (

**c**) Deformation in Z Direction. (

**d**) Deformation in Z Direction Magnified by 10 Times.

**Table 1.**Chemical Composition of Base Metal and Welding Wire [25].

Chemical Composition | C | Mn | Si | S | P | Nb | Cu |
---|---|---|---|---|---|---|---|

AH36 | 0.15~0.18 | 1.20~1.45 | 0.15~0.50 | 0.015 | 0.025 | 0.015~0.025 | / |

ER70S-6 | 0.06~0.15 | 1.40~1.85 | 0.80~1.15 | ≤0.035 | 0.025 | / | <0.5 |

No. | Laser Power (W) | Wire Feeding Speed (mm/min) | Welding Speed (m/min) | Incident Position (mm) |
---|---|---|---|---|

1 | 5000 | 11.8 | 1.5 | 0.5 |

2 | 6000 | 11.8 | 1.5 | 0.5 |

3 | 4000 | 11.8 | 1.5 | 0.5 |

4 | 5000 | 13.3 | 1.5 | 0.5 |

5 | 5000 | 10.3 | 1.5 | 0.5 |

6 | 5000 | 11.8 | 1.8 | 0.5 |

7 | 5000 | 11.8 | 1.2 | 0.5 |

8 | 5000 | 11.8 | 1.5 | 0 |

9 | 5000 | 11.8 | 1.5 | 1.5 |

No. | Type | Laser Power (W) | Arc Power (W) | Wire Feeding Speed (mm/min) | Welding Speed (mm/min) | Incident Position (mm) | Incident Angle (°) |
---|---|---|---|---|---|---|---|

1 | Simulation | 4700 | 7000 | / | 2500 | 0.5 | 12 |

2 | Simulation | 4700 | 7000 | / | 2500 | 1 | 12 |

3 | Simulation | 4700 | 7000 | / | 2500 | 1.5 | 12 |

4 | Experiment | 5000 | / | 11.8 | 1500 | 0.5 | 12 |

5 | Experiment | 5000 | / | 11.8 | 1500 | 0 | 12 |

6 | Experiment | 5000 | / | 11.8 | 1500 | 1.5 | 12 |

No. | Type | Laser Power (W) | Leg Height (mm) | Middle Width (mm) | Minimum Penetration (mm) | Fusion Depth (mm) |
---|---|---|---|---|---|---|

1 | Simulation | 4200 | 2.752 | 0.721 | 0.021 | / |

2 | Simulation | 4700 | 2.761 | 0.951 | 0.112 | / |

3 | Simulation | 5200 | 2.768 | 1.212 | 0.212 | / |

4 | Simulation | 5700 | 2.772 | 1.523 | 0.322 | / |

5 | Experiment | 5000 | 4.628 | / | / | 1.678 |

6 | Experiment | 6000 | 4.708 | / | / | 1.926 |

7 | Experiment | 4000 | 4.494 | / | / | 1.498 |

No. | Type | Arc Power (W) | Wire Feeding Speed (mm/min) | Leg Height (mm) | Middle Width (mm) | Minimum Penetration (mm) | Fusion Depth (mm) |
---|---|---|---|---|---|---|---|

1 | Simulation | 5500 | / | 2.612 | 0.912 | 0.035 | / |

2 | Simulation | 6500 | / | 2.738 | 0.924 | 0.098 | / |

3 | Simulation | 7000 | / | 2.795 | 0.929 | 0.124 | / |

4 | Simulation | 7500 | / | 2.891 | 0.943 | 0.143 | / |

5 | Experiment | / | 11.8 | 4.628 | / | / | 1.678 |

6 | Experiment | / | 13.3 | 5.038 | / | / | 1.872 |

7 | Experiment | / | 10.3 | 4.349 | / | / | 1.327 |

No. | Type | Welding Speed (mm/min) | Leg Height (mm) | Middle Width (mm) | Minimum Penetration (mm) | Fusion Depth (mm) |
---|---|---|---|---|---|---|

1 | Simulation | 2200 | 2.876 | 1.397 | 0.257 | / |

2 | Simulation | 2300 | 2.814 | 1.236 | 0.216 | / |

3 | Simulation | 2400 | 2.783 | 1.125 | 0.112 | / |

4 | Simulation | 2600 | 2.751 | 0.816 | 0.035 | / |

5 | Experiment | 1500 | 4.628 | / | / | 1.678 |

6 | Experiment | 1800 | 4.414 | / | / | 1.457 |

7 | Experiment | 1200 | 4.829 | / | / | 1.886 |

Laser Power (W) | Wire Feeding Speed (mm/min) | Welding Speed (m/min) | Incident Position (mm) |
---|---|---|---|

5000–6000 | 10.3–13.3 | 1.2–1.8 | 0–0.5 |

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## Share and Cite

**MDPI and ACS Style**

Wei, N.-K.; Shi, J.; Yang, R.-D.; Xi, J.-T.; Luo, X.-M.; Yin, X.-Y.; Zhang, R.-X.
Numerical Simulation and Experimental Analysis on Seam Feature Size and Deformation for T-Joint Laser–GMAW Hybrid Welding. *Materials* **2024**, *17*, 228.
https://doi.org/10.3390/ma17010228

**AMA Style**

Wei N-K, Shi J, Yang R-D, Xi J-T, Luo X-M, Yin X-Y, Zhang R-X.
Numerical Simulation and Experimental Analysis on Seam Feature Size and Deformation for T-Joint Laser–GMAW Hybrid Welding. *Materials*. 2024; 17(1):228.
https://doi.org/10.3390/ma17010228

**Chicago/Turabian Style**

Wei, Nai-Kun, Jin Shi, Run-Dang Yang, Jun-Tong Xi, Xiao-Meng Luo, Xu-Yue Yin, and Rui-Xue Zhang.
2024. "Numerical Simulation and Experimental Analysis on Seam Feature Size and Deformation for T-Joint Laser–GMAW Hybrid Welding" *Materials* 17, no. 1: 228.
https://doi.org/10.3390/ma17010228