scholarly journals Fast Prediction for Resistance Spot Welding Deformation Using Inherent Strain Method and Nugget Model

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7180
Author(s):  
Takeshi Chino ◽  
Atsushi Kunugi ◽  
Toshikazu Kawashima ◽  
Goro Watanabe ◽  
Cao Can ◽  
...  
Keyword(s):  
Resistance Spot Welding ◽  
Spot Welding ◽  
Welding Deformation ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds ◽  
Fast Prediction ◽  
Inherent Strain ◽  
Inherent Strain Method ◽  
Strain Method

In a car body, there exist thousands of resistance spot welds, which may induce large deformation during the manufacturing process. Therefore, it is expected that automotive industries will develop a method and a computing system for the fast and simple prediction of its deformation. Although the inherent strain method has been used for the fast prediction of arc welding deformation, it has not been applied to resistance spot welding so far. Additionally, the electrical-thermal-mechanical coupling analysis for the deformation induced by resistance spot welding is complicated and much more time-consuming. Therefore, in this study, a nugget model of the resistance spot weld has been developed, and the inherent strain method is extended for use in the fast prediction of resistance spot welding deformation. In addition, the deformation of a vehicle part with 23 resistance spot welds was efficiently predicted within around 90 min using the inherent strain method, displaying good accuracy compared with the measurement.

Resistance Spot Welding of Low Carbon Steel to Austenitic CrNi Stainless Steel

2014 ◽  
Vol 875-877 ◽  
pp. 1499-1502 ◽  
Author(s):  
Ladislav Kolařík ◽  
Miroslav Sahul ◽  
Marie Kolaříková ◽  
Martin Sahul ◽  
Milan Turňa
Keyword(s):  
Stainless Steel ◽  
Carbon Steel ◽  
Weld Joint ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds

The contribution deals with resistance spot welding of low carbon steel to austenitic CrNi stainless steel. The thickness of welded dissimilar steels was 2 mm. DeltaSpot welding gun with process tape was utilized for welding of the above-mentioned combination of steels. Resistance spot welds were produced under different welding currents. The welding currents used were 7 kA, 7.5 kA and 8 kA, respectively. Optical microscopy, microhardness measurement across the weld joint and EDX analysis across the weld joint interface were used to evaluate the quality of resistance spot welds of dissimilar steels.

scholarly journals Experimental and numerical analysis of shunting effect in resistance spot welding of Al2219 sheets

2016 ◽  
Vol 64 (2) ◽  
pp. 425-434 ◽  
Author(s):  
M. Jafari Vardanjani ◽  
A. Araee ◽  
J. Senkara ◽  
J. Jakubowski ◽  
J. Godek
Keyword(s):  
Finite Element ◽  
Heat Affected Zone ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Numerical Solutions ◽  
Potential Temperature ◽  
Model Verification ◽  
Spot Welds ◽  
Resistance Spot ◽  
Shunting Effect

Abstract Few aspects of shunting effect have been studied so far. Shunting effect in resistance spot welding (RSW) occurs when the electrical current passes through the previous spot welds. Value of this current depends mostly on distance, number, and size of previous spot welds. This will cause some dimensional and metallurgical changes in welding nugget as well as heat affected zone (HAZ). In this study, shunting effect of RSW is considered by finite element method (FEM) and the results are compared to experiments performed on aluminum alloy 2219. Weld spacing together with welding current and time are considered to discover the effect of shunting current in the final quality of nugget. A three factor experiment design has been performed to find the significance of factors and interactive effects, as well as finite element model verification. Electrothermal and mechanical interactions are considered in the FEM. Experimental and numerical solutions have yielded similar results in terms of welding nugget properties. Asymmetry in electrical potential, temperature, stress distribution and geometry of shunted nugget is predicted and verified directly or indirectly. Intense effect of shunting current on nugget height, asymmetric growth of heat affected zone (HAZ) toward previous welding nugget, as well as concentration of alloying elements along grain boundaries are also discovered.

Inherent Strain Method and Thermal Elastic-Plastic Analysis of Welding Deformation of a Thin-Wall Beam

2008 ◽  
Vol 24 (4) ◽  
pp. 301-309 ◽  
Author(s):  
Y.-X. Wang ◽  
P. Zhang ◽  
Z.-G. Hou ◽  
C.-Z. Li
Keyword(s):  
Temperature Field ◽  
Strain Analysis ◽  
Welding Deformation ◽  
Thin Wall ◽  
Analysis Method ◽  
Elastic Plastic ◽  
Plastic Analysis ◽  
Inherent Strain ◽  
Inherent Strain Method ◽  
Strain Method

AbstractThe transient thermal process of a thin-wall beam with CO2 Gas Metal Arc Welding (GMAW) is analyzed by Finite Element Analysis Method (FEA). The thermal input is simplified as transient section body heat sources and loaded as its actual sequence in the analysis. The transient temperature field obtained can represent the basic characteristics of the real welding process and can be used as the foundation of thermal elastic-plastic analysis. Based on the temperature field, thermal elastic-plastic FEA is performed on the thin-wall beam. The distribution and change of the welding deformation, stress and strain are obtained and compared with the experiment results. Also an improvement can be presented on the inherent strain method. Using the inherent strain method, the welding deformation of the thin-wall beam is calculated. The temperature loading method is developed to load the variable inherent strain value expediently. The loading of inherent strain value on spatial welding line that is unparallel to the global coordinate axis is achieved with the application of element coordinate system. Comparison with the experiment results shows that both the thermal-elastic-plastic analysis and inherent strain analysis method can be used to predict the welding deformation effectively, the results calculated by both the thermal-elastic-plastic analysis and inherent strain analysis are close to the test measure results.

scholarly journals Optimization of resistance spot welding parameters for microalloyed steel sheets

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Ján Viňáš ◽  
Ľuboš Kaščák ◽  
Miroslav Greš
Keyword(s):  
Bearing Capacity ◽  
Resistance Spot Welding ◽  
Spot Welding ◽  
Microalloyed Steel ◽  
Welding Time ◽  
Spot Welds ◽  
Load Bearing Capacity ◽  
Load Bearing ◽  
Resistance Spot ◽  
Steel Sheets

Abstract The paper presents the results of resistance spot welding of hot-dip galvanized microalloyed steel sheets used in car body production. The spot welds were made with various welding currents and welding time values, but with a constant pressing force of welding electrodes. The welding current and welding time are the dominant characteristics in spot welding that affect the quality of spot welds, as well as their dimensions and load-bearing capacity. The load-bearing capacity of welded joints was evaluated by tensile test according to STN 05 1122 standard and dimensions and inner defects were evaluated by metallographic analysis by light optical microscope. Thewelding parameters of investigated microalloyed steel sheets were optimized for resistance spot welding on the pneumatic welding machine BPK 20.

Critical Dimensions of Tensile-Shear Specimen for Resistance Spot Welds

2015 ◽  
Vol 782 ◽  
pp. 177-182
Author(s):  
Xue Tuan Cui ◽  
Yuh J. Chao ◽  
Zhen Luo ◽  
San San Ao ◽  
Fu Yu Yan
Keyword(s):  
Spot Welding ◽  
Tensile Shear ◽  
Spot Welds ◽  
Shear Tests ◽  
Critical Dimensions ◽  
Resistance Spot ◽  
Test Standards ◽  
Shear Specimen ◽  
Resistance Spot Welds ◽  
Different Dimensions

Resistance spot welding is used extensively in auto industry. Every commercial vehicle has 4000-5000 spot welds. The weld ability, performance, and reliability are therefore important issues in design. Tensile-shear tests are normally performed to evaluate the weld quality and acquire the mechanical strength of spot welds. However, different industry test standards often specify different dimensions for the tensile-shear specimen. In this work, we investigate the failure load and energy absorption of the spot welds made of Q235 steel using tensile-shear specimens of different dimensions. The objective is (a) to determine a specimen dimension independent geometry for failure strength, and (2) to call attention to the deficiency of some of the test standards.

Inherent Strain Method for Residual Stress Measurement and Welding Distortion Prediction

2016 ◽  
Author(s):  
Ninshu Ma ◽  
Keiji Nakacho ◽  
Takahiko Ohta ◽  
Naoki Ogawa ◽  
Akira Maekawa ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Welded Joints ◽  
Stress Measurement ◽  
Three Dimensional ◽  
Diffraction Method ◽  
Welding Distortion ◽  
Fast Prediction ◽  
Inherent Strain ◽  
Inherent Strain Method ◽  
Strain Method

Inherent strain method was employed to measure the distribution of three dimensional welding residual stresses in several multi-pass welded joints of thick pipes and thick cladded plates. Since a function expression approach to the distribution of inherent strains was developed, the measuring efficiency for three dimensional internal welding residual stresses in complicated welded joints was improved a lot. The residual stresses measured by inherent strain method were compared with the high cost stress release method and neutron diffraction method. Furthermore, inherent deformation parameters, which are defined by integrated values of inherent strains on transverse sections, were used for the fast prediction of welding distortion in assembling structures. Based the predicted welding distortion, its mitigation methods such as tack welding and jig constraint were discussed.

Resistance Spot Welding of Unequal Thickness Low Carbon Steel Sheets

2009 ◽  
Vol 83-86 ◽  
pp. 1205-1211 ◽  
Author(s):  
Majid Pouranvari ◽  
Pirooz Marashi
Keyword(s):  
Carbon Steel ◽  
Spot Welding ◽  
Peak Load ◽  
Low Carbon Steel ◽  
Low Carbon ◽  
Tensile Shear ◽  
Spot Welds ◽  
Resistance Spot ◽  
Resistance Spot Welds ◽  
Dissimilar Thickness

Resistance spot welding is the dominant process for joining sheet metals in automotive industry. Even-thickness combinations are rarely used in practice; therefore, there is clearly a practical need for failure behaviour investigation of uneven-thickness resistance spot welds. The aim of this paper is to investigate and analyze the failure mode and failure mechanism of dissimilar thickness low carbon steel resistance spot welds during tensile-shear overload test. Microstructural investigations, microhardness tests and tensile-shear tests were conducted. Mechanical properties of the joint were described in terms of peak load, energy absorption and failure mode. It was concluded that weld nugget size and the strength of the thinner base metal are the controlling factors of the peak load and energy absorption of dissimilar thickness spot welds.

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